*** START OF THE PROJECT GUTENBERG EBOOK 42073 ***

    ELECTRIC GAS LIGHTING


    HOW TO INSTALL

    ELECTRIC GAS IGNITING APPARATUS
    INCLUDING THE JUMP SPARK
    AND MULTIPLE SYSTEMS

    FOR USE IN

    HOUSES, CHURCHES, THEATRES, HALLS, SCHOOLS,
    STORES OR ANY LARGE BUILDINGS

    ALSO THE CARE AND SELECTION OF SUITABLE BATTERIES.
    WIRING AND REPAIRS


    By H. S. NORRIE
    (NORMAN H. SCHNEIDER)
    (_Author of “Induction Coils and Coil Making”_)


    FIRST EDITION


    NEW YORK
    SPON & CHAMBERLAIN
    12 CORTLANDT STREET

    LONDON
    E. & F. N. SPON, LIMITED,
    125 STRAND

    1901


    Entered according to Act of Congress in the year 1901
    By SPON & CHAMBERLAIN
    in the office of the Librarian of Congress, Washington, D. C.


    THE BURR PRINTING HOUSE, FRANKFORT AND JACOB STS., N.Y.




PREFACE


The Electric Light possesses the great advantage over gas, in that it
can be turned on or lighted from a distance. The customary means of
igniting gas with a match or taper is both dangerous and often
inconvenient. The inventive genius of modern times has evolved a means
of lighting gas by electricity which is both reliable and easy of
application. It requires no very complicated devices, nor does it
necessitate a deep knowledge of electrical matters for its
installation. The object of the following pages is to enable any one
possessing ordinary mechanical ability to construct much of the
apparatus used, or at least to successfully erect it and keep it in
operation.

We beg to thank the following firms for the use of illustrations:
Edwards & Co., Mott Haven, New York; A. L. Bogart, New York; Wm.
Roche, New York; The Electric Gas-Lighting Co., Boston, Mass., and The
Manhattan Electrical Supply Co., New York.




CONTENTS.


    CHAPTER I.

    INTRODUCTORY REMARKS.

    Introduction; means of producing sparks; Induction--Simple
    induction coils--Ruhmkorff Coils                                 1


    CHAPTER II.

    MULTIPLE GAS LIGHTING.

    Application of induction coils to gas-lighting--Forms of burners
    used--Pendant Burners--Ratchet Burners--Stem Burners--Welsbach
    Burners--Burners for Acetylene Gas--Burners for
    Gasolene--Automatic Burners                                      7


    CHAPTER III.

    CONNECTIONS AND WIRING.

    How to connect up apparatus--Wiring a house--Locating breaks or
    short-circuits--Wiring in finished houses--General remarks      26


    CHAPTER IV.

    PRIMARY COILS AND SAFETY DEVICES.

    How to make a simple induction coil--Automatic Cut-outs--The
    Syracuse Cut-out--Boston Cut-out--Edwards’ Cut-out              46


    CHAPTER V.

    LIGHTING OF LARGE BUILDINGS.

    Series or Jump Spark System--Burners used--How to Wire--Edwards’
    Condenser System--Switches for series lighting--How to make a
    2-inch spark, Ruhmkorff Coil                                    55


    CHAPTER VI.

    HOW TO SELECT BATTERIES FOR GAS LIGHTING.

    Electrical Rules--Electromotive
    force--Amperes--Resistance--Selecting a battery--Arrangement of
    battery--Series--Multiple--How to get high voltage or large
    current--The Leclanche Cell--The Samson Cell--The Dry Cell and
    how to make one--The Edison-Lalande Cell--The Fuller Cell--Care
    and maintenance of batteries                                    78




    LIST OF ILLUSTRATIONS.


       FRONTISPIECE--COMPLETE WIRING PLAN FOR A HOUSE.
     1 DIAGRAM OF SIMPLE CIRCUIT                                     2
     2 DIAGRAM OF SIMPLE CIRCUIT WITH SPIRAL                         2
     3 DIAGRAM OF SIMPLE CIRCUIT WITH SPIRAL AND GALVANOMETER        2
     4 DIAGRAM OF CIRCUIT WITH IRON CORE                             4
     5 DIAGRAM OF RUHMKORFF COIL                                     4
     6 ELEVATION OF RUHMKORFF COIL                                   6
     7 PENDANT BURNER                                                7
     8 BURNER CIRCUIT                                                8
     9 PLAIN BURNER                                                 10
    10 RATCHET BURNER                                               11
    11 STIFF-PULL PENDANT                                           12
    12 STEM BURNER                                                  14
    13 ARGAND BURNER                                                15
    14 WELSBACH BURNER                                              16
    15 ACETYLENE BURNER                                             17
    16 PUSH BUTTON                                                  19
    17 BARTHOLDI BURNER                                             21
    18 BOSTON AUTOMATIC                                             22
    19 CONCEALED AUTOMATIC                                          24
    20 DIAGRAM WIRING ONE “AUTOMATIC” FROM TWO PUSHES               27
    21 DIAGRAM WIRING ONE “AUTOMATIC” AND TWO PENDANT BURNERS       28
    22 SIMPLE SWITCH CONNECTIONS                                    33
    23 DETAILS OF AUTOMATIC CONNECTIONS                             35
    24 DETAILS OF CELLAR AUTOMATIC CIRCUITS                         35
    25 NUT WRENCH                                                   40
    26 AUTOMATIC OPERATED BY DOOR-TRIP                              44
    27 PRIMARY COIL                                                 46
    28 SYRACUSE CUT-OUT                                             50
    29 BOSTON CUT-OUT                                               51
    30 DETAILS CUT-OUT ROD--NORMAL                                  52
    31 DETAILS CUT-OUT ROD--OPERATING                               53
    32 BULB CUT-OUT                                                 54
    33 JUMP SPARK BURNER                                            56
    34 WELSBACH BURNER FOR SERIES LIGHTING                          56
    35 PILLAR BURNER                                                56
    36 CIRCUIT FOR JUMP SPARK GAS LIGHTING                          57
    37 INSULATOR                                                    59
    38 EDWARDS’ CONDENSER                                           60
    39 EDWARDS’ BURNER                                              61
    40 EDWARDS’ BURNER                                              61
    41 DIAGRAM OF EDWARDS’ CONDENSER CIRCUIT                        62
    42 CIRCUIT FOR JUMP SPARK SWITCH                                64
    43 ELECTROMAGNETIC TRAILER                                      66
    44 DIAGRAM OF RUHMKORFF COIL CIRCUIT                            68
    45 WINDINGS OF SECTIONS                                         73
    46 SECTIONAL DIAGRAM                                            74
    47 CONTACT BREAKER                                              75
    48 CONTACT KEY                                                  76
    49 FALL OF POTENTIAL DIAGRAM                                    79
    50 SERIES ARRANGEMENT                                           81
    51 MULTIPLE ARRANGEMENT                                         82
    52 LECLANCHE CELL                                               84
    53 SAMSON CELL                                                  87
    54 NEW STANDARD CELL                                            90
    55 EDISON-LALANDE CELL                                          92
    56 FULLER CELL                                                  94
    57 GRENET CELL                                                  95




CHAPTER I.

INTRODUCTORY REMARKS.


The enormous number of fires arising from the use of matches, and the
great convenience and freedom from danger of the electric method of
gas lighting, are alone sufficient reasons for the issue of these
pages.

The veriest tyro in electrical operations knows that electricity will
cause a spark, and most persons are aware that the spark possesses
considerable deflagratory powers, varying with the character of the
spark. In electric gas lighting a spark of the proper character is
passed across a jet of gas and ignites it. Sparks can be produced by
various means: friction, battery current, induction either galvanic or
electro-magnetic, by a Wimshurst or Toepler Holtz machine, or an
induction coil operated by a battery. For our purposes we will
consider only the latter; the former are rarely used, being uncertain
and unwieldy.

Of batteries there are many kinds, and although all will produce
sparks, yet for electric gas lighting those made for intermittent work
and classed as open circuit cells are to be preferred. Open circuit
batteries, which will be fully described in a subsequent chapter,
include the Leclanche, and most of the so-called “dry” cells.

[Illustration: FIG. 1.]

[Illustration: FIG. 2.]

[Illustration: FIG. 3.]

If two wires be attached to a cell of battery _B_, one to the carbon
or positive pole and the other to the zinc or negative pole, and their
free ends be tapped together, minute sparks at _C_ will be observed
each time the wires _separate_ (Fig. 1). If now a coil of insulated
wire _S_ be included in the circuit, Fig. 2, upon repeating the make
and break of contact, the sparks will be much increased. This arises
from _induction_, each adjacent turn of wire acting upon its neighbor.
To better understand the action of induction, we will consider the
following examples: Fig. 3. _A_ is a circuit in which is the battery
cell _B_. _C_ is a second circuit lying close to but well insulated
from circuit _A_. _G_ is a galvanometer in which a magnetized needle
swings right or left each time a current is passed through a coil of
wire encircling it. Now, although there is no battery cell in circuit
_C_, yet the needle will swing each time the circuit _A_ is closed or
opened; that is, each time the wire ends are touched together or
separated. This swing of course indicates that a current is passing
through circuit _C_, but as there is no battery or other source of
electrical energy included in it, it is clear that it arises from the
action of the current in circuit _A_. In point of fact, the needle
swings one way when the circuit is closed and the reverse way when it
is opened; but the greater swing on opening the circuit indicates the
greater strength of the _induced_ current at the moment the current
ceases to flow in circuit _A_. Note that these current impulses are
only momentary. In the case of our single coil, Fig. 2, each turn of
wire acted upon itself in a similar manner to the circuit _A_ upon
circuit _C_.

[Illustration: FIG. 4.]

[Illustration: FIG. 5.]

An iron rod or bundle of iron wires, _P_, inserted in the coil, Fig.
4, but carefully insulated from it, will immensely increase the
inductive effects and consequently the spark. This arrangement
constitutes the simple primary coil used in pull-down or pendant and
automatic burners. This spark is often a source of inconvenience; it
appears wherever a circuit including similar coils is made and broken.
In telegraph apparatus at key and relay contacts it is noticeable; in
fact, the writer has used temporarily a pair of electro-magnets from a
telegraph sounder and obtained spark enough to operate a gas lighting
burner.

To produce a long spark which will jump across an air gap, a more
complicated form of coil is needed, one which more closely corresponds
to the experiment noted in Fig. 3. The simple primary coil has here
another coil of finer wire, _S_, wound on it but carefully insulated
from it (Fig. 5). This second coil, or “secondary,” has a vast number
of turns of fine wire as compared with the primary, which has only
comparatively few turns of coarse wire. A primary coil of 40 feet of
No. 14 B. & S. copper wire would be inserted in a secondary coil of
perhaps 16,000 feet of No. 36 B. & S. This secondary coil, in fact all
the apparatus constituting the induction coil, must be most highly
insulated, as the electromotive force of the spark is tremendous, and
it would be liable to pierce its way through and into the internal
winding and so destroy the apparatus. The circuit in the primary is
made and broken either by a hand key or by an automatic
contact-breaker at _C_. With a large coil, the intensity of the spark
at _G_ is such that it will jump an air-gap of from one-eighth of an
inch to over three feet.[1]

  [1] See Norrie, _Induction Coils and Coil-Making_.

This combination of coils and contact-breaker is generally known as a
Ruhmkorff or intensity coil, and is shown in elevation in Fig. 6.

[Illustration: FIG. 6.]




CHAPTER II.

MULTIPLE GAS LIGHTING.


[Illustration: FIG. 7.]

As we have already seen how a spark is exhibited at an interrupted
contact, the means of its application to gas lighting will be
considered. Fig. 7 represents the most generally used kind of electric
gas burner or “pendant burner.” Its application is shown in Fig. 8.
The wire _W_ from the coil _C_ is attached to the brass insulated
collar carrying the contact _S_. The other wire from coil _C_ and
battery _B_ is attached to the gas pipe _G_. As the burner is also
screwed into the gas pipe itself, the circuit would be closed were it
not for the gap at _A_ on the burner, caused by the collar carrying
the contact _C_ and wire _W_, being insulated from the burner pillar
_P_. When, however, a pull is given to the burner arm chain so as to
cause the end of the spring _R_ to strike contact _C_ in passing,
contact is made and broken, and a spark passes which ignites the gas
issuing from the burner tip, the gas having previously been turned on.
A piece of chain with a metal ball is attached to the burner arm in
order to pull it down. In this class of burner there are many
different makes differing only in minor details.

[Illustration: FIG. 8.]

Fig. 9 shows a form of pendant burner which has no platinum contact,
but has a broad lug on the insulated collar which is scraped against
by the spiral spring when the arm is pulled down. It will be seen that
the lug is not held by an insulated collar on the burner top, but is
on the extension of an arm attached to the burner pillar by a large
screw and insulating washers. The circuit wire goes under the smaller
screw seen on the lower part of the contact arm, this forming a
strong and neat form of attachment.

[Illustration: FIG. 9.]

Now it has heretofore been necessary to turn on the gas before pulling
the chain of a pendant burner, but as this is not always desirable the
ratchet burner is made. Fig. 10 shows burner carrying a toothed wheel,
which is partly rotated when the arm is pulled down. This wheel is
mounted on the stem of a valve which opens or shuts according to the
point of rotation, and thus shuts off or admits the gas to flow up to
the burner. One pull of the arm turns the gas on; at the same time the
wipe spring touches the contact on burner collar, and the gas lights.
A second pull and the wheel, rotating, turns off the gas. In all
burners of this class a spring is provided to carry the arm up and
back into its original position ready for another pull. Some burners
do not make contact when the arm flies back, thus saving battery
current.

[Illustration: FIG. 10.]

[Illustration: FIG. 11.]

Fig. 11 is an improved form of burner wherein the movable electrode
does not pass through the gas flame, neither do the electrodes come in
contact with each other when the gas is being turned off. Reference
to the cut will show a pin protruding from the base of the coiled
spring electrodes, which pin is so arranged as to come in contact with
the short end of the pull-arm. When this pull-arm is pulled down it
pushes up this pin, elongating the spiral spring electrode
sufficiently to make and break contact at the fixed electrode on the
burner collar. This burner can be fitted with a porcelain candle slip
if desired to match the imitation candle burners.


STEM BURNERS.

Objection is sometimes made to the ordinary chain pulls from the fact
that they jar the fixtures, and also are liable to bend the fixture
branches from the strain used in operating the arm. To overcome these
objections the stem style of burner is manufactured (see Fig. 12).
This stem, it will be seen, carries a convenient key at the end, which
is turned either right or left as in an ordinary gas-cock. The moving
contact only makes contact when the gas is being turned on and
lighted. When turning it off, the arm is retracted so as not to touch
the fixed electrode, thus saving battery current.

[Illustration: FIG. 12.]

Fig. 13 is a simple lighting attachment for an Argand burner. The
moving lever which carries the pull has a German silver spiral spring
on its top end. This strikes against the lug projecting from the
circuit-wire arm and makes a spark. The lower part of the circuit-wire
arm has a screw and washers for ready attachment, and is strongly and
substantially made.

[Illustration: FIG. 13.]

A means of igniting the gas from a Welsbach burner is shown in Fig.
14, and is so simple as to need no further explanation.


ACETYLENE BURNERS.

Owing to the deposits of carbon, it is necessary to construct burners
for acetylene gas in a different and more substantial manner than
those designed for coal gas.

[Illustration: FIG. 14.]

The best arrangement is depicted in Fig. 15, which has a pilot-tube
burner as well as the two main tips. On turning the key, gas is
admitted to both main and pilot burners, but the electrode in
breaking contact only ignites the gas at pilot burner, which, in its
turn, acts as a lighter for the main burner. Turning the main burner
out, the pilot light can be left burning if desired, giving a small
light, it being not feasible to turn _down_ the main burner owing to
the before-mentioned carbonization.

[Illustration: FIG. 15.]

The orifice of an acetylene burner is much smaller than that of a coal
gas burner, the former burning about one-half foot per hour, against
six or seven feet of the latter.


BURNERS FOR GASOLENE.

The flame from this gas is hotter than that of coal gas, and deposits
so much more carbon that a slight modification is necessary in the
construction of burners for it. The details can be readily seen on
observation of a burner, being simply in the adjustment of the
contacts and their operation. It is better, however, to use a larger
coil and a stronger battery for gasolene gas lighting than would be
needed for coal gas--say, 6 cells of Samson, or large-size New
Standard dry battery and a 10-inch coil having about 4 pounds or more
of wire on it.


AUTOMATIC BURNERS.

[Illustration: FIG. 16.]

There are several forms of these burners, but the principle of all is
the same. A gas burner protrudes from the top of a brass case which
encloses the actuating mechanism. This mechanism consists generally of
two electro-magnets, the armature of one opening the valve and
allowing the gas to flow, at the same time vibrating a platinum-tipped
rod against an electrode upon the burner collar. This produces a
series of sparks at the burner tip which ignites the gas. A second
magnet is provided which shuts the valve and extinguishes the gas.
Some devices use one electro-magnet to both open and close the valve,
but the majority have double electro-magnets. The circuit is worked
from a push button, Fig. 16, situated wherever desired; pressure on a
white button lights the gas and on a black one shuts it off.


BARTHOLDI AUTOMATIC BURNER.

Instead of a rotating stop-cock, as in other automatics, a gravity
valve is employed in the Bartholdi, which is held to its seat by the
weight of the armature and connecting stem, as shown in figure 17.
When the gas is turned off the valve rests upon its seat, as indicated
in the cut. By a closure of the electric circuit at the turn-on
button, two of the helices _M P_ are energized, causing the armature
_J_ to be lifted, thus, by means of the stem _H_, raising the valve
_G_ from its seat into the dotted position, and opening the gas way so
that the gas may issue to the tip, as shown by the arrows. At the same
time, the top of the valve strikes against the end of the lever _W_,
causing the circuit to be broken at the spark points _T U_,
resulting in a continuous sparking as long as the finger presses the
button. The magnet when raising the armature has also twisted or
partially revolved it, so as to bring the notch _d_ in the armature
over the end of the hook _e_, as shown in the dotted lines. When the
circuit is broken by lifting the finger from the button, the notch
falls into the hook and the valve is locked open.

[Illustration: FIG. 17.]

To extinguish the flame, the turn-off button is pressed, when a second
magnet (not shown in cut) lifts the armature and twists it in the
opposite direction, so that when the circuit is broken the armature
falls free to its normal position, closing the valve.

[Illustration: FIG. 18.]


THE ADVANCE AUTOMATIC.

This automatic burner, Fig. 18, is typical of the class having two
magnets, one to open valve and light gas, and another to close valve
and extinguish the light. It embodies an improvement over the older
types of burners in that the binding posts are mounted on a rubber
strip held by two screws, thus preventing the twisting and loosening
so common heretofore. It also allows of the valve being opened and gas
lighted by means of a match should the battery fail.


VIBRATOR BURNER.

This is an automatic burner which has no valve mechanism, but ignites
the gas only. It is generally placed in a cluster or ring where the
burners are close enough to light by contagion. It is much smaller in
diameter than the regular automatic burners, being but one and
three-quarter inches in diameter.


ARGAND AUTOMATIC BURNERS.

Automatic burners are also made for Argand, but present no radical
difference in construction over the regular type.


THE CONCEALED AUTOMATIC BURNER.

[Illustration: FIG. 19.]

This automatic, Fig. 19, consists of two iron-clad magnets, placed one
above the other, between which is located a gas valve. Through an
extension of the latter a pin is driven, one end acted upon by the
upper armature to open the valve and ignite the gas, the other by the
lower armature which serves to close the valve and extinguish the
flame. Around the burner is placed a porcelain candle slip of 3/4-inch
diameter and from 4-3/4 inches in length upwards.




CHAPTER III.

CONNECTIONS AND WIRING.


Fig. 20 shows how to connect up an automatic burner with two pushes;
thus one can be downstairs in the hall and the other upstairs,
allowing one to either extinguish or light the gas from either place.
The value of this arrangement is obvious; it allows one to light up
the hall before descending at night, or to put out the gas after one
is safely upstairs. Again, an automatic burner can be put in the
cellar and lighted and extinguished from the head of the
cellar-stairs, saving matches and danger of fire.

Fig. 21 shows the connections of one automatic burner and two pendant
or rachet burners. _P P_ are the pendent burners, _A_ the automatic
burner, _C_ the primary coil, _S_ the buttons which control the
automatic burner, _M M M_ the cells of battery, of which there
should be at least four, if not six. A low-resistance cell must be
used here, as before mentioned, one that gives not _less_ than 5
amperes on short circuit. It will be seen here that one side of the
battery is connected to ground (or gas pipe), the circuit being
completed owing to the burners being themselves screwed into the gas
pipe. Care must be taken, however, to first see that no insulating
bushings have been used at the gas fixtures, as is done in wiring for
electric light. In this case a double circuit will have to be run.

[Illustration: FIG. 20.]

[Illustration: FIG. 21.]

In wiring up an automatic burner with two electro-magnets, two wires
are run, one from the black button and one from the white button on
push-plate. Most burners have binding posts inside the case, the wires
running through a rubber-bushed hole in the base. One of the greatest
defects in the old style automatics arose from the two binding posts
being fixed on a hard rubber block, which was held by one screw to the
burner top. This screw got loose at times and the block used to twist,
making it hard to tighten the wires. But improvements have been made
in this direction, the later burners having a block with a projection
which engages in a hole in the cover, and is held by two screws.

If the push has been set in place, and all wiring done, connect up the
burner, first ascertaining to which binding post the two wires run.
This is done by having one button pressed, the lighting (white) one,
for example, and then touching the binding post with either wire. The
lighting armature will buzz violently when touched, whereas the
extinguishing one only strikes once when contact is made. When only
one person is working, a pin can be wedged in the push so as to keep
the circuit closed.

In setting up these burners care must be taken not to bend contacts or
alter adjustments, and absolute precaution is necessary that no wires
touch where uninsulated. A cause of trouble is a dirty burner which
does not allow the gas to strike the contact spark. The collar
carrying the second contact may shift, or perhaps become
short-circuited in a pendant or ratchet burner; a strip of asbestos
will remedy this.


BURNER DISTRIBUTION.

In fitting a house with electric lighting burners, the question of
selection is best solved as follows: For the main hall and foot of the
cellar-stairs, use the automatic burner. For other hallways,
dining-room, drawing-room, and bathroom use ratchet burners which turn
on and light gas when chain is pulled. For bedrooms use plain pendant
burners; automatics and ratchets add an element of danger, in that
they may not turn off gas, or may leak. Most of this type on the
market are as reliable as it is possible to make them, but still
accidents will happen.

The frontispiece shows a diagram of the wiring in a dwelling house of
medium size, dividing it into three sections, each section being
controlled by a switch--either a hand switch or one of the automatic
cut-out switches elsewhere described. The burners are distributed as
follows:

No. 1 in the front cellar, pendant or ratchet.

No. 2 in the rear cellar at foot of stairway is an automatic burner
controlled from kitchen above.

Nos. 3 and 4 ratchet burners on chandeliers in drawing-room and
dining-room.

No. 5 ratchet or pendant in kitchen.

No. 6 pendant in bedroom.

No. 7 ratchet or pendant in bathroom.

No. 8 pendant in bedroom.

No. 9 pendant in bedroom.

Nos. 10, 11, and 12 pendants in bedroom.

No. 13 automatic burner in hallway operated from pushes in lower and
in upper hallways.

The articles required for this job are as follows:

Two automatic burners.

Three gas lighting push-buttons and bases. Pendant and ratchet burners
according to number of lights in rooms.

Six cells--open circuit battery.

One three-lever switch.

One 8 or 10 inch spark coil.

Three pounds No. 16 patent finish office wire.

Two ounces No. 24 gas-fixture wire.

One pound tinned 3/8" staples.

Few square inches tinfoil.

Small roll insulating tape.

Tools: 4-inch screwdriver, pocket knife, 4-1/2-inch side-cutting
pliers, hammer, piece of sandpaper.

The simple section switch is shown enlarged in Fig. 22. The wires 1,
2, and 3 are from their respective circuits and terminate at the
switch arms _A A A_. The wire from the battery _B_ and coil _C_
runs to _each_ switch-stud _S S S_. If trouble shows on the line,
each circuit can be thrown off by moving its switch arm until the
fault is located. If it is not found at once, and the battery is weak,
(test each cell with an ordinary electric bell), open all the circuits
until the battery is recuperated, and disconnect the battery wire
from the switch. Then attach the battery wire to the bell and touch
each switch lever with a wire from the other binding post of the bell.
If there is a short circuit on any section, the bell will ring or
tremble when the arm is touched.

[Illustration: FIG. 22.]

On the contrary, if the burners fail to work and no sign of a short
circuit can be thus obtained, it is evident that a wire is broken or
a screw is loose.

To locate a break, connect up the bell as just described and attach
the testing wire to the switch with all levers closed; this is
actually putting the bell in series with the battery, coil, and
ground. Then hunt for the break. Take a long piece of wire and fasten
one end to a ground pipe. Then touch the other end to the circuit wire
in the cellar as far as you can go, baring the insulation in spots,
but carefully re-insulating it again. If there is no break in the
cellar, the bell will ring loudly at each contact. Next, proceed to
the next floor and repeat the operation, gradually working _away_ from
the battery. As soon as you pass the break, the bell will fail to
respond. Two persons here are better than one, as it may be necessary
to go quite a distance from the bell before finding the trouble.

Fig. 23 shows details of the wiring from the hall light to the two
push-buttons. A wire is run right down from the top push _T_, middle
connection, past the lower push _L_, where a similar branch joins it,
until it reaches the section switch. The lighting and extinguishing
wires from the lower push run up and are joined on to the similar
wires from the top push, which latter wires go directly through the
floor and ceiling to the automatic burner _A_.

[Illustration: FIG. 23.]

[Illustration: FIG. 24.]

Fig. 24 is the detail of the wiring for the cellar automatic burner
_A_, from the push _P_, and is so clearly shown as not to require
further explanation.

The secret of success in gas-lighting work is careful wiring. The
platinum tip of the vibrating rod is often bent, either by accidental
blow or by the continual hammering against the tip on the collar. This
often causes an open circuit when the lighting armature refuses to
buzz. Again, soot will form, causing weak action owing to imperfect
contact. Examine, adjust, and clean; here, as in all electrical work,
contacts must be clean.

In general wiring, use weatherproof office wire, or, better still,
well-made electric light wire. For ordinary house work No. 16 B. & S.
gauge is preferable; smaller wire means higher resistance and less
current at burner. For braided office wire, No. 16 runs about 95 feet
to the pound, No. 18 about 135 feet to the pound. The cheaper grades
of wire without the patent finish or extra insulation are not worth
using; sooner or later trouble will ensue, and once a house is wired,
it is no pleasant job to hunt trouble, especially if the wire was put
on before the plaster. In modern buildings in large cities, the use of
conduit tubes has become general, but the handling of these conduits
comes more under the province of the electric-light wireman and less
within the scope of these pages.

In wiring new wooden buildings do not draw wires too tight; the wood
may expand and either break wire or cause a weakening of the
insulation. In wiring before the plaster is put on, always leave a
good length free, so it will not be covered up by the plasterers.

The wire used on the gas fixture is of a special kind, being made for
the purpose. It is made in two sizes, No. 22 and No. 24 B. & S. gauge,
and with three windings of cotton, three outer layers of cotton and
one of silk, or three windings of cotton which is soaked in fireproof
preparation, and then wound with silk.

As the piece used is generally short, these small sizes are sufficient
in carrying capacity. After wiring up a fixture, this fine wire can be
tied on to the pipes, etc., with thread, and a good coating or two of
shellac varnish applied. When this is dry, the thread can be removed
and the shellac will hold the wires on to the fixture. On no account
finally connect up the battery to a circuit when shellacking the wire.
Wait until the shellac is thoroughly dry and _hard_--at least half a
day, if possible.

White lead is generally used at the joints where the burner screws
into the fixture, but tinfoil wrapped round the joint will give good
service. It prevents leaks and ensures a good contact.

The ground connection at the battery must be first-class; do not be
content with just wrapping a few turns of wire around the pipe in the
cellar (assuming the battery is in the cellar), but clean and scrape
the pipe; clean at least two feet of the wire, wind it tightly and
evenly on the pipe and _solder_ it. There is a pipe-clamp made which
is clamped on the pipe and the wire attached to that, but it must be
properly put on a clean surface.


WIRING FINISHED HOUSES.

In wiring finished houses, especially wooden ones, the wires can be
run along skirting boards, and often pushed out of sight in the space
between the floor and the skirting. This is quite permissible, as the
wires, unlike electric-light wires, carry no dangerous current; but
waterproof wire becomes preferable, as the water used in washing a
floor will often creep under and rot the insulation. In going
upstairs, wires can often be run in the fluting of a moulding along
the stairway, and be quite inconspicuous; but wherever possible, fish
the wires up inside the wall. The main thing to be considered in
wiring is that the wires are large enough, well insulated, all joints
well made and taped and put where there is no danger of injury. Rats
have a habit of gnawing paraffin-coated insulation, and it is well to
run such in metal tubes. In joining or splicing wires, do it in a
thorough manner, and solder if possible. Never use the old bell-hanger
joint--the one in which the ends of the wires are merely looped
together. Strip insulation and scrape or sandpaper bright about three
inches of each wire to be spliced. Then, placing the bare wires across
each other about three-quarters of an inch from the insulation,
tightly wind the loose bare ends of each around the bare inside
portion of the one it is being spliced to. A touch of solder will
prevent trouble from oxidation, after the adhesive tape has been
wrapped on. Attention to details like these will often ensure the
satisfactory working of the job.

A handy tool for gas-lighting wiring is shown in Fig. 25. One end is
bored out to fit the small nuts on the ratchet and pendant burners,
and the other is filed flat for use as a screwdriver.

[Illustration: FIG. 25.]

A case may arise where there is electric light on the same chandelier
as the gas lights, and that an insulating bushing has been screwed in
between the fixture and the pipe. In this case it will be necessary to
run two wires to each burner, the pipe common return being now
unavailable. Another scheme is to interpose an insulating bushing
under each burner; then the second or return wire need only be run
from the burner to the gas pipe _outside_ the main bushing. But the
local fire-insurance rules must first be consulted.

Most ceiling gas fixtures will admit of the fixture wire being run
inside the brass shell, which makes a neater job. But the very best
of insulation must be used, and great care be taken that it be not
abraded. It should be shellacked or otherwise insulated before use.
The electric-light fixture wires are admirable for use here if there
is room.

For concealed work in a finished house, locate the position of the
fixture under the floor of the room above by measuring both in the
room where the fixture is and in the room above. Then cut out a piece
of the floor, drill up from underneath through the fixture
plaster-rose with a fine drill, and push the fixture wire up. The main
wire can be laid under the carpet, or along the floor-crack in the
upstairs room.

In wiring up wall-fixtures, push-buttons, etc., it is often possible
to fish the wire up from the floor by punching a hole at the fixture
and inserting a piece of chain (made for the purpose), attached to a
long and stout thread. Then drill into the skirting near the floor
plumb underneath the first hole and fish for the chain with a piece of
wire having a hook on the end of it. Where fixtures have brass
rosettes, these can be removed by (generally) unscrewing the fixture,
_but first shut off the gas_ at the meter, or plug the hole; this may
seem unnecessary advice, but experience warrants its being given. When
the chain is fished out, a piece of wire can be attached to the thread
and pulled through in turn. In most cases its point of exit at the
fixture can be concealed by the rosette, through a hole in which it
passes. Take care that the edges of this hole do not cut the
insulation. Care must be taken at every step in gas-lighting wiring.

In wiring up a push-button, screw all wires tightly under their
respective binding screws, and then cover wherever possible with
adhesive tape. As the wires must be somewhat loose to allow of the
connections being made at the back of the push-button at the wall,
they will have to be carefully pushed into the hole, and if they are
not tightly held by screws, trouble will result. It is a good plan,
when using fine enough wire, to make a sort of eye at the end of the
wire and pass the screw through this, instead of merely giving the
wire end a turn around the screw and then driving the screw home. Of
course washers should be used wherever an ordinary screw holds a bare
wire.


AUTOMATIC BURNER OPERATED BY DOOR.

One of the uses to which an automatic burner can be put is in
conjunction with an electric door-spring, lighting when the door is
opened, but preferably extinguished by independent push. In this case,
a form of trip spring should be used which would only make contact
during a portion of the travel of door. Such a trip is shown in Fig.
26.

_A_ is automatic burner; _C_, the primary coil; _B_, the battery; _T_,
a swinging trip piece of brass hinged in brass plate, _P_, which is
screwed over the door in such manner that the door opening in
direction of the arrow will cause the trip _T_ to strike against the
spring _S_, and make contact. This spring is insulated from the plate
_P_ by the hard rubber block _R_.

On the door being opened, the trip will make contact long enough to
light the burner and will then fall back as the door passes. On
shutting the door, the trip will be raised and will fall as the door
passes, but will not make contact. Or, if so desired, it can be made
to operate a second contact to extinguish the burner by fixing a
second insulated spring so it will be pressed when the top of trip
makes a downward movement--as when the door passes it in shutting.

[Illustration: FIG. 26.]

Various applications of automatic burners in connection with burglar
alarms will suggest themselves, but in these cases the utmost care
must be taken that the apparatus is in good working order; failure to
light might cause the room to be filled with gas, and serious results
ensue.

For those persons who use gas stoves and are mechanically inclined, an
arrangement of an alarm clock with an automatic burner will enable
them to light up without getting out of bed, or perhaps even waking
up.




CHAPTER IV.

PRIMARY COILS AND SAFETY DEVICES.


To construct a primary coil such as used with pendant or automatic
burners presents no difficulty. The most convenient sizes are those 8
to 10 inches in length and about 3 inches in diameter. It is quite
common to speak of these coils as _8 or 10 inch coils_; to the
writer’s knowledge this has been taken to mean a Ruhmkorff or
double-wound induction coil, giving a free 8 or 10 inch spark.

[Illustration: FIG. 27.]

To make such a coil (Fig. 27), proceed as follows: Prepare a spool by
gluing a paper or fibre tube 3/4 inch in outside diameter by about
1-16 inch thick into square or round spool ends three inches square,
one-half inch thick, and having each a centre hole just large enough
to admit of the tube being held tightly. These ends should be firmly
fixed on the tube; a pin or two driven through tube into end will
assist in strengthening the joint. Now wind on the tube about 3 pounds
No. 12 B. & S. cotton-covered magnet wire. This will give about six
layers of 80 turns each, nearly 500 turns in all, a total length of,
say, 150 feet, measuring .25 ohm. The ends of the wire are to be
brought out through holes drilled in the spool ends, and can be fixed
to brass binding posts on those ends.

Into the paper tube push as many iron wires 8 inches long by No. 22 B.
W. gauge as will fill it. These iron wires can be tightened finally by
driving in at each end, a stout wire nail.

Although not absolutely necessary, a coat or two of shellac varnish
applied to the windings will make a better insulation. Shellac varnish
is readily made by dissolving one part gum shellac in four parts of
alcohol. For coils which are likely to be in damp places, a good
saturation with insulating compound, such as P. & B. paint, will
render them waterproof. The need for good insulation in these primary
coils is not so urgent as in Ruhmkorff coils, owing to the lower
potential of the current.

A smaller coil can be made with No. 14 B. & S. wire where the battery
is of higher resistance (or gives less than ten amperes on short
circuit). The remarks on battery selection on another page will be
found to meet application here.


AUTOMATIC CUT-OUTS.

Where there are a number of burners to be installed in different parts
of a house, it becomes desirable to wire in a number of circuits. As
one end of the circuit is already grounded, a second ground will cause
material injury to the battery if not detected in time. It becomes,
therefore, necessary to be able to open a grounded circuit without
affecting all the lights in a house. This is possible with the
multiple circuit arrangement by using a switch, either automatic or
operated by hand.

The simplest form of danger signal is the relay electric bell
attachment, which device is mounted on the end of the gas-lighting
coil. It consists of an armature which closes a circuit when
attracted by the coil core, in which circuit are included a battery
and electric bell.

Now when an ordinary pendant or ratchet burner is pulled, it only
sends a momentary current through the coil, enough to magnetize the
core, but not enough to attract the armature sufficiently long for the
bell to ring. But if a short circuit or ground should occur, the
armature is held against the contact long enough to cause the bell to
ring and give warning. In some cases a constant ringing attachment is
added, in which case the bell rings until some one stops it.


THE SYRACUSE CUT-OUT.

This is a most ingenious device for opening a short circuit, depending
on its action upon the sluggish movement of glycerine (Fig. 28).

A sealed glass tube pivoted near its centre contains a portion of
glycerine sufficient to considerably overbalance it and keep one end
down. A soft iron armature is attached to this tube in such manner
that each time a current flows through a pair of electro-magnets, the
attraction of the armature causes the tube to tilt and the glycerine
flows along to the other end. Now it will be readily seen that if the
tube is only tilted for a second or so, the slow-moving glycerine will
not have flowed sufficiently to the end to overbalance it, but it
requires an attraction of the armature for a considerable period. This
electro-magnet is in circuit with the gas-lighting wires, the tube
being provided with contacts in such manner that, when fully tilted,
the circuit is broken. The momentary jerks imparted to the armature by
the operation of a pendant or automatic burner will not be enough to
permanently tilt the tube and break contact, but a short circuit will
hold the armature tight down, until the increasing weight of glycerine
causes the tube to open the circuit.

[Illustration: FIG. 28.]

[Illustration: FIG. 29.]


AUTOMATIC SECTIONAL CUT-OUT.

[Illustration: FIG. 30.]

This cut-out, Fig. 29, is representative of the class which use
clockwork, and is both simple and reliable. The house circuit is in
series with an electro-magnet which controls a clockwork having a long
pinion shaft. This clockwork starts and runs while the house circuit
is closed, as on operating a burner, but stops when the circuit is
opened and flow of current ceases. The wires leading to different
circuits in the building run through a number of contact springs
mounted on sliding rods, which have teeth cut on the under side (Fig.
30). These rods have soft iron armatures on the opposite ends from the
contact springs, which rest over electro-magnets, also connected to
the house circuits. When the clockwork starts, the pinion shaft
revolves, but does not engage in any of the sliding rods, as they
just clear it. Should a heavy or continuous current pass through one
of the electro-magnets, it attracts the armature on the corresponding
rod (Fig. 31), and the turning pinion engages in the teeth, drawing up
the rod and breaking contact.

[Illustration: FIG. 31.]

Fig. 32 is a form of battery protector which works on the gravity
principle. Here each section is governed by a rocking contact,
operated by two glass bulbs partially filled with a volatile fluid
(such as ether), and joined by a glass tube. In one of these bulbs is
a platinum wire which is included in the circuit and heats upon the
passage of a strong or continuous current. If the circuit is closed
too long, the heating of the platinum wire causes the fluid to flow
into the upper bulb, and, as the bulbs are pivoted, the increased
weight of the upper bulb now overbalances the rocker and breaks the
circuit on that section.

[Illustration: FIG. 32.]




CHAPTER V.

LIGHTING OF LARGE BUILDINGS.


The jump spark system is used where it is desired to light clusters of
gas jets situated in inaccessible places, or a number of them
simultaneously. The spark from a Ruhmkorff coil, being made by a
contact broken at the coil and not at the burner, can be divided up
among a number of simple burners placed in series. One of the burners
used and known as the Smith jump spark burner is shown in Fig. 33. The
wires from the coil are attached to the electrodes shown on each side
of the burner, and the spark jumps across the gap, situated nearly
over the burner orifice. There is a guard-flange of mica round the
lower part.

Fig. 34 shows the manner in which the jump spark is applied to a
Welsbach burner. A small porcelain clip carrying the spark-gap wires
is held on the top of the burner chimney. The electrodes project down
into the chimney so that a draught of air cannot carry the stream of
gas away from the spark-gap.

[Illustration: FIG. 33.]

[Illustration: FIG. 35.]

[Illustration: FIG. 34.]

Fig. 35 shows a burner intended for the stage of a theatre, or where
the lights are located in dangerous and inaccessible places. The
burner is made of porcelain upon which are spun the metal top and
bottom. One electrode is also clamped around it, allowing of
adjustment and better insulation.

[Illustration: FIG. 36.]

These burners are used in series, as shown in Fig. 36. _B B B_ are the
burners; _S S_, the secondary wires from the Ruhmkorff coil, _I_; _P
P_, the primary coil wires from battery, opened and closed by means of
the key, _K_.

It is often possible to place plain burners close enough so that they
can ignite by contagion. In this case one of the plain burners is
removed and replaced by a multiple burner, as above.

It is customary to allow sixteen burners to one inch of spark, in
which case the spark gaps are adjusted about one-sixteenth of an inch
apart. A coil giving a 2-inch spark would operate 32 burners, but
actually it would be found preferable to omit a few, so as to make
allowance for any slight leak. A spark of over 2 inches is hard to
handle, although often used; it is better to make up a number of
circuits of, say, 30 burners each, and operate them alternately by a
suitable switch.

The wire used to connect the burners is generally bare, although an
insulated wire is sometimes used. But the electromotive force of a
2-inch spark is so high that it is better to run the wires so they do
not come near anything liable to cause a leak. The remarkable tendency
of these high-tension currents must be most carefully guarded against;
indeed, it is what makes this style of gas lighting so often
unsuccessful. A damp wall, gilt wall-paper, a gas pipe hidden in the
plaster, will often lead off the current. The wires should be at least
50 per cent. further off from any object than the spark length; that
is, a 2-inch spark circuit should be at least 3 inches away from a
wall, and the further the better. It cannot be too strongly urged that
every precaution be taken to keep the wires away from objects other
than their insulators.

[Illustration: FIG. 37.]

Fig. 37 shows the special form of insulator used. It is made of the
highest grade glaze filled porcelain, and the screw is passed into it
and holds against the lower end as far away from the wire as possible.

Glass tubes should be passed over the wires wherever they come near
any metallic object, that is, within sparking distance.


EDWARDS’ CONDENSER SYSTEM.

This system differs from the foregoing in that the spark-gaps are
connected in multiple, instead of series, and each burner is provided
with a small but efficient condenser.

[Illustration: FIG. 38.]

It prevents trouble should a wire break between burners, in which
event only one burner would be out of commission, whereas in the first
method, the whole number in that series would suffer. It is also more
sure in action and presents less liability of the spark jumping to the
ground. The burner pillars need not be made of porcelain or lava; in
fact, the electrodes can be readily attached to the existing burner.
Fig. 38 is a condenser consisting of a small oval piece of mica, on
each side of which is fastened, with insulating varnish, a
spatula-shaped piece of tinfoil. One foil sheet is attached to the
line, the other to the burner electrode. These condensers must not be
allowed to get wet or their efficiency will be impaired.

[Illustration: FIG. 39.]

[Illustration: FIG. 40.]

Figs. 39 and 40 are the most generally used burners, the wire from the
condenser being attached to the lug or top electrode, which is
insulated from the burner by means of the mica plate to which it is
riveted. The burner pillars are of course grounded through their
being screwed into the gas pipe. The circuit is shown in Fig. 41. _I_
is the induction or Ruhmkorff coil, in the primary circuit of which is
the key, _K_, controlling the current from the battery, _B_, and
across which is bridged the condenser, _C C_. When the coil vibrator
is used, the condenser _C C_ can be omitted, that of the coil itself
serving instead. _S_ is the wire leading from the secondary terminal
of the coil to the burner condenser, _C_, which, in turn, are
connected to the electrodes on the burners, _P P_, as before noted.
The other secondary wire is grounded preferably to the gas pipe
itself.

[Illustration: FIG. 41.]

Where a lot of burners are placed together, as in a ring, it is often
feasible to light them by contagion, one tip only being connected to
the coil circuit, the others lighting from it and conveying the flame
around to the rest. This avoids multiplicity of circuits, or, perhaps,
too many burner gaps on one circuit; but the one burner may fail to
light, whereas, where all are fitted, the chances of failure are less,
especially in the Edwards condenser system.


SWITCH FOR JUMP SPARK-LIGHTING.

In a switch for controlling the current of the secondary coil it will
be evident that the utmost attention must be paid to matters of
insulation. The object of such a switch is to control a number of
circuits; for example, as it is not advisable to put more than 20 to
25 burners on one circuit, a case requiring the lighting of 100
burners would necessitate some means of passing the current to each
circuit in turn. This is shown in Fig. 42, in which _S_ is a hard
rubber plate, provided with a revolving metal arm and handle, _H_, and
four contact points, _P_, which latter receive the ends of the wires
from the groups of burner condensers _B_ by means of nuts or binding
posts. The wire from the secondary of the coil is run to the
switch-handle, _H_, great care being taken that it does not pass near
to the circuit wires, or contact points. Revolving the switch-handle
connects the secondary wire to each circuit in turn. It will be
noticed that, unlike a battery switch, this one has a large base, long
switch-arm, contact points situated far apart, and every precaution
taken to control the passage of the high-tension current. The base
should always be of rubber or glass. Shellacked-wood, or such
substitutes, are productive of trouble.

[Illustration: FIG. 42.]

When it is desired to light automatically a number of burners from a
distance, the Trailer (Fig. 43), is used. This is a switch similar to
above, but the arm is revolved by means of toothed wheels by the
electro-magnet shown on the back. As it is never desirable to
unnecessarily prolong the secondary wires, this device admits of the
switch being put near the circuits, and yet being operated from afar.

[Illustration: FIG. 43.]


RUHMKORFF COIL.

Fig. 44 shows a diagram of a Ruhmkorff coil, the letters referring as
follows:

_C_ the iron core, _P_ the primary coil wires, _I_ the insulating tube
between primary _P_ and the secondary coil _S_. In small coils this
may be dispensed with, and a heavy layer of paraffin wax laid over the
primary coil. _D D_ are the ends of the secondary, showing sparking
taking place between a pair of balls (or between the electrodes of a
gas burner); _R_ is a stiff spring fastened to the coil base and
carrying a soft iron hammer, which is attracted toward the iron core,
_C_, when current passes through the primary coil and magnetizes it.
_L_ is a battery, _J_, a condenser, to be more fully described later
on. When the spring _R_ touches the adjustment screw _A_ at _B_, as
they are insulated from each other, contact is made and reference to
circuit will show that the current from battery _L_ flows through
primary coil, magnetizing the core and attracting soft iron hammer on
_R_. As this bends forward, it breaks contact at _B_, the core loses
its magnetism and the spring flies back, to again make contact. This
is repeated many times per second.

[Illustration: FIG. 44.]

As a heavy spark occurs at _B_ on the break of contact, the condenser,
_J_, is attached at _M K_. This is a series of insulated tinfoil
sheets, which has the property of nullifying the spark at _B_, and so
preventing the waste of platinum with which both adjustment screw _A_
and spring _R_ are equipped.

A Ruhmkorff coil differs from a simple primary coil in three main
points. Two separate coils instead of one; high insulation, and a
primary coil of few turns. In the simple coil we desired
self-induction; here, we desire to avoid it as much as possible.

The average size Ruhmkorff coil, for jump spark work, would be one
giving a 2-inch spark, specifications for which are as follows:

_Spool_--Nine inches long by one inch in diameter. End cheeks 4 inches
high by 3 inches wide.

_Core_--Sufficient soft iron wires, 9 inches long by No. 22 B. W.
gauge as will fill the spool tube.

_Primary_--Two layers No. 14 B. & S. gauge cotton-covered copper wire.

_Secondary_--Two and one-half pounds No. 36 B. & S. gauge double
cotton or silk-covered magnet wire wound in four sections (or more
than four sections, if feasible).

_Condenser_--Seventy sheets tinfoil 4 by 7-1/2 inches; 80 sheets
condenser paper 5 by 8 inches.


SPOOL.

This should be made up of a fibre tube 9 inches in length by about
1/16 inch thick, and should be firmly fixed into the spool ends. If it
be glued in it should also be pinned as well; it is easily possible to
drive in a few screws passing through the tube into the spool ends,
particularly as the soft iron core, being of loose wires, will adapt
itself to the slightly projecting screw-heads. Remember that this
spool must be made strong; if it comes apart during the winding
process, much trouble will ensue, and perhaps all the wires lost or
ruined. For reasons to be seen later, do not affix the right-hand
spool end yet, but have it ready. The core consists of as many fine
iron wires, say of No. 22 B. W. gauge, as can be forced into the tube,
but the core can better be added after the windings are all in; that
is, in such cases where a rigid spool tube is used.


PRIMARY WINDING.

This consists of two layers of No. 14 B. & S. gauge cotton (or silk)
covered copper magnet wire, and should be evenly and tightly laid on.
For winding coils, a lathe is a most handy machine, or the spool can
be mounted on a spindle and rotated by hand. It is not feasible here
to give all details of coil-construction; reference should be made to
the many excellent works on the subject. The two ends are brought out
through holes in the spool ends, as indicated for the simple primary
coil before described. After winding, the wire is to be well basted
with melted paraffin wax until it is saturated, any excess being
scraped off so as to leave a smooth cylindrical surface for the
secondary coil. Half a dozen turns of stout paper or oiled silk is now
to be wound on, and enough paraffin wax added to leave an insulation
at least one-quarter of an inch around the outside of the winding. The
right-hand end of spool, where the end was not attached, will require
a little care that the wire does not run off; but, as only two layers
are to be wound, it is an easy thing to do.

When the primary coil is finished off, cut three pieces of hard rubber
four inches square, with a central hole just big enough that they may
be slipped on over the primary coil to form divisions into which the
secondary wire goes. These can be fixed equal distances apart by means
of removable wooden blocks, which are taken off as each section is
wound.


SECONDARY COIL.

The secondary coil consists of about 2-1/2 pounds No. 36 B. & S. gauge
silk or cotton-covered magnet wire, wound evenly in layers in the
sections on the primary coil. Before any wire goes into a section, it
must be seen that the division fits tight to the primary coil. It will
be best to pour around the coil some melted paraffin wax so as to form
an insulating ring, and prevent any possibility of the spark creeping
under the section division into the next. The actual operation of
winding presents no difficulty other than those of keeping the wire
from damage and getting as even layers as possible. If each layer is
separated from its neighbor by a strip of paraffined paper, it makes
even winding easier, and better insulation. As to the insulating of
the secondary coil, it can be done in a variety of ways. The coil can
be soaked in molten paraffin until saturated, or the wire can be made
to pass through a dish of molten paraffin while on its way from the
wire reel to the coil. In the latter case the wire must be guided by
means of glass rollers, as the wax would harden rapidly if touched by
the fingers. In connecting up the sections, the similar ends are to be
joined; that is, the inside ends to inside ends, and outside ends to
outside ends, as per diagram (Fig. 45). This will bring two outside
ends free for attachment to binding posts. Fig. 46 shows direction of
winding and connecting the two middle coils, _A C_ being the inside
layers next to primary and _B D_ the outside layers.

[Illustration: FIG. 45.]

An outside coat of paraffin wax is now given to the coil and a
wrapping of waxed paper laid on. Then, if desired, a cover of
sheet-rubber or a layer of cloth can be put on over all, to finish the
job.


BASE, KEY, AND CONDENSER.

[Illustration: FIG. 46.]

The base for a Ruhmkorff coil generally resembles an oblong shallow
box. The coil is mounted on the lid, and the condenser inside the box,
the connections being made on the lower side of the lid. It is
preferable, except for appearance’ sake, to make all connections
outside the box, but this is left to the worker’s choice.

[Illustration: FIG. 47.]

_The Condenser_ is made up of 70 sheets of tinfoil each about 4 inches
by 7-1/2, and 80 sheets of clean white paper 5 by 8 inches placed
alternately, and saturated with paraffin wax. The tinfoil sheets are
laid so that about 1/2 inch projects out of the paper sheets at each
end, the alternate sheets coming out at the same end, and the
projecting pieces being bent together gives the effect of a pair of
tinfoil sheets insulated from each other, aggregating the sum of all
the small ones.

[Illustration: FIG. 48.]

The coil can now be attached to the base by means of screws passing
through the lid into the coil ends. If a vibrating contact breaker be
desired, reference to Fig. 44 will show method of connection. Fig. 47
shows details of a contact breaker of similar design. _R_ is hammer
head of soft iron, _S_ a spring about thickness of clock spring and
3/8 inch wide or more. _B_ is contact point, both spring and
adjustment screw _A_ being fitted with platinum contacts. _C_ is a
check nut, to hold _A_ from turning. _I_ is an adjustment to tighten
or loosen spring _S_, by means of a lug which it carries on its
shaft. It is well insulated from pillar carrying _A_, by the hard
rubber bushing, _I_.

The condenser is laid in the box under the coil and attached as in
Fig. 44; that is, one set of sheets to the contact pillar, and the
other set to the adjustment screw.

For gas-lighting work, it is generally preferable to use a contact or
strap key (Fig. 48), instead of a vibrator. The key can be mounted on
coil base, in which case the condenser will be attached in same manner
as for the vibrator.




CHAPTER VI.

HOW TO SELECT BATTERIES FOR GAS LIGHTING.


Before entering into a description of the various batteries used in
electric gas lighting, it will be well to briefly consider a few
simple electrical rules bearing upon the subject.

A current of electricity has _electromotive force_, or _difference of
potential_ figured in _volts_, and _current_ figured in _amperes_.

For example we will use the _water_ analogy (Fig. 49). Two tanks, _A_
_B_, on the same level, are connected by a pipe _C_.

Supposing tank _A_ be filled with water and the pipe, _C_, to be
opened; the water will flow along _C_ into _B_ until the level in each
tank is equal. So long as there is a difference of level, there will
be a pressure in _C_, owing to the water behind it.

Replacing the tanks _A_ and _B_ by unequally electrified bodies, and
the pipe _C_ by a conductor of electricity, the flow of water is
represented by the tendency of the electrified bodies to equalize
themselves by a flow of current along the conductor, _C_.

To sum up: The difference of level is now difference of potential, the
pounds pressure along the pipe being expressed as electromotive force
in _volts_.

[Illustration: FIG. 49.]

The quantity of water flowing along the pipe is measured, as
electricity, in amperes. As the quantity of water passing in a given
time is regulated by the size of the pipe and its own pressure, so the
quantity of electricity is also regulated. A conductor of electricity
offers resistance to the flow of current according to its sectional
area and the material of which it is composed, this resistance being
expressed in _ohms_. The greater the voltage and lower the resistance,
the more current. This law, and its kindred applications, are
expressed as follows:

    _C = E/R._

_C_ is current in amperes, _E_ electromotive force in volts, and _R_
resistance in ohms.

Thus a wire with a resistance of 50 ohms would pass 2 amperes with an
electromotive force of 100 volts. To find resistance when other two
factors are known, the formula is

    _R = E/C._

In selecting a battery for work, regard must be made to the current
required, and its period of flow. For energizing a gas lighting
primary coil, the current must be large, but is only required
occasionally, the battery standing idle for long periods. In this case
the class called open circuit cells are preferable, as they contain no
strong acids and do not deteriorate to any extent when not in use. Of
such class is the Leclanche-Samson, Monarch, carbon cylinder, and most
so-called dry cells. As the resistance in a conductor affects the
current flow, so it does in a battery cell; the internal resistance of
a battery is determined by its size, proximity of the elements, etc.
Cells with small zincs and porous cups are of high internal
resistance, those with large sheet zincs and big carbon surfaces, of
low internal resistance. As the primary coil used in gas lighting is
never much over one ohm, a cell of low internal resistance should be
selected. But as the wires leading to the burners must be taken into
account, a number of cells should be used to produce enough
electromotive force to overcome the added resistance. Now battery
cells can be arranged in a variety of ways--in series for higher
electromotive force, and in multiple--for greater current.

[Illustration: FIG. 50.]

Fig. 50 represents the series arrangement; here the zinc of one cell
is connected to the carbon of the next; this adds the electromotive
forces together and thus gives greater ability to overcome resistance,
but it also adds together the resistance of each cell. Thus 4 cells,
each 2 volts and of one-half ohm internal resistance, would, in
series, have an E. M. F. of 8 volts and an internal resistance of 2
ohms, current 4 amperes. Fig. 51 shows four cells in multiple, the
zinc of each cell and the carbons of each cell are connected. Here the
result would be but 2 volts, but the internal resistance would be only
one-quarter, viz: one-eighth of an ohm, current 16 amperes.

[Illustration: FIG. 51.]

The readiest rule for connecting a battery is to arrange it according
to the resistance of the line or outside wiring. So as we will have to
use house-wiring far exceeding in length that on the coil, and
probably of less diameter. Therefore the series arrangement will be
the one to use, and not less than four cells of a low-resistance
battery.


THE LECLANCHE.

This battery consists of a carbon rod surrounded by granular peroxide
of manganese forming the positive pole and a piece of zinc for the
negative pole, both elements being immersed in a solution of sal
ammoniac (chloride of ammonia). If a wire be run _outside_ the
solution and connecting the carbon and zinc, a current of electricity
flows along it. The chemical action taking place is as follows: The
zinc combines with the chlorine of the solution, liberating free
hydrogen and ammonia. The hydrogen appears at the carbon, where it is
acted upon by the oxygen of the peroxide of manganese. If too much
current is taken from the cell, that is, if the wire or circuit be of
too low resistance, the oxidizing action of the peroxide is not rapid
enough, and a film of hydrogen, which is a poor conductor, forms over
the carbon and increases the resistance of the battery--also setting
up what is termed “local action” (actually, a battery opposing a
battery).

After a rest, the hydrogen is absorbed, but a cell rarely regains its
pristine activity after too severe demands upon it. The original
Leclanche batteries were imported from France, the home of the
inventor, but of recent years they are made in the United States,
England and Germany. The most important point to be considered in a
galvanic cell is the purity of its active parts. The zincs should be
as near chemically pure as can be obtained; the peroxide of manganese
of the best quality and perfectly free from foreign substances, and
the sal ammoniac the purest that can be manufactured. The actual
difference in work between a battery so constructed, and the average
cheap cell sold at a price to catch the unwise, is tremendous. And
this difference is indicated, not only in work, but when the battery
is at rest. Local action in a cheap battery will exhaust it even when
it is not in circuit, whereas a battery cell of good material will
remain in good order for months without more attention than the
addition of water or sal ammoniac. It has been often remarked that the
batteries made to-day are inferior to those made years ago, but it is
only true of the cheap-priced cells; if a good price is paid and
attention given to securing a well made cell, the output will be as
satisfactory.

[Illustration: FIG. 52.]

To set up a Leclanche cell, proceed as follows: Put six ounces of sal
ammoniac into the glass jar; fill the jar one-third full of _clear_
water and stir. Put in the porous cup and fill the jar with water up
to its neck, pouring a few teaspoonfuls of water into the hole in
porous cup. When the cell is in working condition, the level of the
solution will be found to have receded, owing to absorption by the
porous cup. To prevent the creeping of sal ammoniac up the neck of jar
and on to the terminals of the cell, a layer of paraffin is applied to
neck of jar and porous cup. Should this need renewing, vaseline can be
used, or any heavy grease, care being taken that it does not get on
electrodes or where the wires are to be fastened. When the cell
refuses to work, throw out old solution, wash porous cup, jar and zinc
in warm water, and replace with new solution. There is a limit, when a
new porous cup must be used, but this can be done when cell does not
work after being treated as above. The electromotive force of the
Leclanche cell is about 1.45, and current on short circuit of nearly
one ampere, depending of course on thickness and porosity of porous
cup, size of zinc, and a few other points.


THE SAMSON CELL.

Fig. 53 is one of the Leclanche group, in which a compound carbon
element displaces the earthenware porous cup. This carbon is composed
of two parts, a hollow-fluted lower piece and a threaded top, which
carries the binding post. In the process of manufacture, the top piece
is heated red-hot and plunged into hot paraffin wax, thus ensuring a
complete diffusion of the paraffin throughout the carbon. In this way
the creeping of salt or solution, and consequent corrosion of
electrodes and failure of cell, are avoided. The lower portion is much
more porous than the upper and is filled with a combination of
pea-carbon and peroxide of manganese held in by a plug at the bottom.
This plug can be removed and new depolarizer added. Directions given
by the manufacturers for renewing this element are to hold the lower
end of the carbon over a burner flame until the plug is softened and
can be removed, or to immerse the extreme lower end of the carbon in
boiling water. After refilling, a cork plug can be used.

[Illustration: FIG. 53.]

The E. M. F. of the No. 2 size is from 1.40 to 1.47 volts, and
current, on short circuit, of 12 to 16 amperes. The No. 2 Special has
same E. M. F., but current of only 5 amperes, being intended where
strong current is not required but quick recuperation. It will be seen
that this cell is far more suited to electric gas-lighting work than
the simple Leclanche, owing to its great current delivery.


THE DRY CELL.

Of so-called dry cells there are numbers on the market at so low a
price that it does not pay to make one’s own. But for those who wish
to do so, the following formula, furnished by Mr. Wm. Roche, of New
Standard battery fame, will be found excellent:

One pint CLEAR WATER.

Five ounces sal ammoniac.

Six ounces zinc chloride.

Dissolve the sal ammoniac in the water thoroughly. Let stand
twenty-four hours. Then add the zinc chloride, and when cool, will be
ready for use.

       *       *       *       *       *

When you have your zinc cup ready, pour a little wax in the bottom, to
insulate; place a piece of blotting-paper inside cup and laying tight
against the zinc, about three turns. The negative element is prepared
as follows: One pound pure carbon, powdered; one pound black oxide
manganese; mix thoroughly. Then add sufficient of above solution to
hold it together without being plastic, as that would be too wet to
tamp.

Moisten your paper in the zinc cup thoroughly. Place your stick or
plate of carbon in centre of zinc cup, hold it there central while you
pack in the carbon manganese element all around it; be sure that
carbon manganese, or negative element, does not touch zinc cup. If it
does, your cell will run down quickly. It is a good precaution to have
your paper half an inch higher than cup when in the cup, and soaked
with the solution. Give it a couple of quick taps on the bench; that
will curl the paper in at the bottom and insure against any internal
short circuit. When your cell is filled up, clean all the carbon
element away from the zinc. Seal, and your battery is ready when
you’ve got the connections on.

[Illustration: FIG. 54.]


THE NEW STANDARD DRY CELL.

The principal sizes of this cell (Fig. 54) are as follows:

    No. 2--5-7/8 × 2-7/16.
    No. 3--3-3/4 × 1-7/8.
    No. 5--6 × 2-9/16.
    No. 6--6 × 3.
    No. 7--7 × 3.

The electromotive force is 1.5 volts, current of the No. 7 size on
short circuit, 24 amperes. Nos. 2, 5, 6, or 7 are most suitable for
electric gas lighting, either by simple primary coil or jump spark
coil.


THE EDISON LALANDE CELL.

This cell (Fig. 55), gives a large, steady current and is of low
internal resistance, but its electromotive force is not high, being
less than .7 volt on closed circuit. Its output of current varies with
the size, type _S_ being .025 ohm internal resistance and capacity of
300 ampere-hours. The Edison Lalande cell can be applied to electric
gas lighting in cases where a large demand is made upon the battery,
for example in church or theatre lighting.

Its elements consist of positive plates of amalgamated zinc suspended
on each side of negative plates of black oxide of copper. The
electrolyte is an aqueous solution of caustic soda. A layer of heavy
paraffin oil is poured on top of the solution to prevent the solution
from evaporating and also to keep the soda crystals from creeping up
and over the rim of the jar.

[Illustration: FIG. 55.]

To set up an Edison Lalande cell, fill the jar up to the brown mark
with clear water; pour in the soda from the tin box, _and stir_. When
thoroughly dissolved, pour on top of the solution one half-inch layer
of _the oil which is sent with the battery_. Then the elements
attached to the cover can be inserted, and the cell is ready for use.

Use care not to splash the solution, as it will burn the clothing and
skin. If any does get on, a little animal grease or vegetable oil will
quickly saponify it.

In the action of this cell the oxide of copper is reduced to metallic
copper and the zincs consumed, it being intended that each element
will require renewal at the same time. Upon picking into the oxide
plate with a sharp-pointed instrument, if the plate is red throughout,
it is exhausted; but, should it show black in its interior, it is
still capable of a little more use, but is preferable to use a new
plate whenever there is but little oxide left.

Never remove the oxide plates from the battery, and do not allow the
solution to be less than one inch above oxide plates.


THE FULLER, OR BICHROMATE CELL.

Although not often necessary in gas-lighting work, there is at times a
demand for a heavy current, such as in lighting a big building, where
a large coil must be operated. At such times a bichromate of potash
cell becomes of service. One of the types is shown in Fig. 56. _J_ is
a jar containing electropoion fluid described below. _C_ is a carbon
plate immersed in this fluid. _P_ is a porous cup holding the zinc,
_Z_, and being filled with a solution of 18 parts common salt, 72
parts water, and one ounce mercury.

[Illustration: FIG. 56.]

The electropoion fluid for the outer jar is made by one pound
bichromate of potash or soda to one gallon of water, mixing in a stone
vessel. When dissolved, add three pounds commercial sulphuric acid
carefully, a little at a time, and stir the mixture constantly as it
gets hot. Always add the acid to the mixture; never attempt to pour
the mixture into the acid, or trouble will result. The sodium salt is
preferable to the potassium, owing to its greater solubility and its
not forming _chrome alum_--a hard precipitate which sticks to jars,
elements, etc., to their detriment.

[Illustration: FIG. 57.]

Fig. 57, a form of battery known as the Grenet battery, is used where
there is no porous cup. The zinc element, _Z_, is mounted on a rod _R_
passing through the cap _G_ of a glass jar, _J_, and can be raised or
lowered into the electropoion fluid which the jar contains. This is a
good scheme where the battery is liable to stand idle for a long
period.


CARE OF OPEN CIRCUIT BATTERIES.

_Terminals._--Take care that the solutions do not splash over
terminals; keep all terminals and binding post screws clean and
bright. See that all wires are tightly clamped in terminals, also that
their ends are clean. A loose contact is productive of infinite
trouble. Examine connections that elements are in proper relation to
each other. If in multiple, to produce large current--zincs together
and carbons together. If in series, for high electromotive force--zinc
to carbon, throughout battery.

_Zincs._--See that the zincs are clean; if crystals form, either
reduce strength of solution with water, or scrape zincs clean, and
watch if repeated. Examine screw which holds wire; it often corrodes,
and makes poor contact in the thread.

A clever device for preserving a rod zinc from the accumulation of
crystals is made by the manufacturers of the Samson cell. It consists
of a thin paper tube which is slipped over the zinc. When the crystals
accumulate so as to impair the cell, the tube is slipped off and a new
one put on. This device increases the internal resistance of the cell
but very slightly.

_Porous cups and carbons._--Wash in warm water. Carbons can be well
soaked in warm water and dried in _sun_, in a place where they will
not accumulate dust. Porous cups should be well soaked in warm water,
and left to drain in a place exposed to dustless air. Examine binding
post holes and screws.

_Solutions._--Do not make too strong. Use not more than six ounces, or
more than four ounces avoirdupois, of chemically pure sal ammoniac to
one cell Leclanche. Warm water can be used for making solutions, if
desired. Some persons drop a teaspoonful of acetic acid in the cell;
it is not recommended. If in a place where sal ammoniac cannot be
procured, use temporarily common table-salt in same proportion;
thoroughly well clean battery first.

Batteries should be kept in a cool dry place. Dry cells should stand
upright, also in a cool place, and an examination made once in a while
of the connections.




    INDEX.


                                      PAGE
    Acetylene Burner                    16
    Argand Automatic Burner             23
    Argand Burner                       14
    Automatic Burner                    19

    Batteries, open circuit              2
    Boston Cut-Out                      51
    Breaks, to locate                   34
    Burner, Acetylene                   16
    Burner, Argand                      14
    Burner, Argand Automatic            23
    Burner, Automatic                   19
    Burner, Bartholdi                   21
    Burners, choice of                  30
    Burner, Concealed Automatic         24
    Burners, Connecting                 26
    Burners, Distribution of            30
    Burner, Gasolene                    18
    Burner, Pendant                      7
    Burner, Ratchet                     10
    Burner, Ring                        23
    Burner, Stem                        13
    Burner, Smith                       56
    Burner, Vibrator                    23
    Burner, Welsbach                    15

    Choice of Burners                   30
    Clockwork Cut-Out                   52
    Coil, Primary                    5, 46
    Coil, Ruhmkorff                      6
    Coil, Secondary                      5
    Connections of Burners              26
    Connections to ground               38
    Contact Breaker                     75
    Cut-Out, Boston                     51
    Cut-Out, Bulb                       54
    Cut-Out, Clockwork                  52
    Cut-Out, Syracuse                   50

    Danger of Burners                   30
    Defects in Burners                  29
    Diagram of Wiring                   31
    Door-Trip                           43

    Edwards’ Burner                     61
    Edwards’ Condenser                  60
    Edwards’ System                     62

    Finished houses, wiring of          38
    Fixtures, wiring of                 40
    Frontispiece                        31
    Fuller Battery                      94

    Galvanometer                         3
    Gasolene Burner                     18
    Gas-fixture wire                    37
    Grenet Battery                      95
    Ground connections                  38

    Hall, Burners for                   30

    Induced Current                      3
    Induction, Action of                 3
    Insulator                           59

    Jump Spark System                   55

    Key Strap                           76

    Lalande Battery                     92
    Leclanche Battery                   83

    Multiple, Batteries in              82

    Negative pole                        2

    Open circuit batteries               2

    Pendant Burner                    7, 9
    Positive pole                        2
    Primary Coils                       46
    Push Button, to wire                42

    Ratchet Burner                      10
    Ring Burner                     23, 63
    Ruhmkorff Coil                   6, 67

    Samson Battery                      87
    Secondary Coil                       5
    Section Switch                      33
    Series method                       57
    Series, Batteries in                82
    Shellac varnish                     38
    Smith Burner                        55
    Sparks, to produce                   1
    Spool                               70
    Standard Battery                    90
    Stem Burner                         13
    Switch, Automatic                   66
    Switch, high tension                64
    Switch, Section                     33
    Syracuse Cut-Out                    50
    System, Edwards’                    62

    Trailer                             66

    Varnish Shellac                     38
    Vibrator Burner                     23

    Welsbach Burner                     15
    Wimshurst Machine                    1
    Winding Coil                        74
    Wire for general use                36
    Wire, gas-fixture                   37
    Wire, office                        36
    Wire, Ruhmkorff Coil                70
    Wiring finished houses              38
    Wiring of Fixtures                  40
    Wiring of Push Button               42


       *       *       *       *       *


New Standard Dry Battery

All sizes for all systems of Bells, Telephones, Burglar Alarms and Gas
Lighting. Prices according to size and quantity.

New Standard “Autogas” Dry Battery

For very heavy work. Gas Mobiles, Lights, etc. No. 2 set, weight 27
lbs., neat oak case, $6.00 per set.

New Standard Jump Spark Rhumkorff Coils, $12.00 each.

New Standard Flashlight.

For use around Gasolene Engines, Automobiles, Launches, Clothes
Closets, etc. $2.00 each.

This light will positively give equal to fifteen hours actual service.
A $5.00 article for $2.00.

Complete catalogue for the asking.


    William Roche,

    Inventor and M’f’r,

    42 Vesey St., N. Y. City

    Dealer in Battery Materials,
    Chemicals, Etc.


    Have a Look
    Into our Store

when in need of anything in the Electrical line of whatever nature.

We deal in everything and carry a good stock.

CATALOGUE ON

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    J. JONES & SON,
    64 Cortlandt St., New York City.


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Copper, Electrics, Enamels, Glass, Gold, Iron, Steel, Liquors Lead,
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    CONTENTS

Symbols and the signs of operation. The equation and the unknown
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uses of common logarithms. Compound multiplication and the binomial
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CROSS SECTION PAPER.

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    PRACTICAL HANDBOOK ON
    Gas Engines
    With Instructions for Care and Working of the Same.

    _BY G. LIECKFELD, C.E._

    Translated with permission of the Author by
    _GEORGE RICHMOND, M.E._

    WITH A CHAPTER ON OIL ENGINES

    CONTENTS

Choosing and installing a gas engine. The construction of good gas
engines. Examination as to workmanship, running, economy. Reliability
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Foundation. Arrangement for gas pipes. Rubber bag. Locking devices.
Exhaust pipes. Air pipes. Setting up gas engines. Brakes and their use
in ascertaining the power of gas engines. Arrangement of a brake test.
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General remarks. Gas engine oil. Cylinder lubricators. Rules as to
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Precautions when opening gas valves, removing piston from cylinder,
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    120 pages, illustrated, l2mo, cloth, $1.00.


    THE FIREMAN’S GUIDE

    A Handbook on the Care of Boilers

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    CONTENTS OF CHAPTERS

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low, foaming, priming.

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state of the boiler, blowing out, refilling the boiler.

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    HOW TO RUN
    Engines and Boilers

    Practical Instruction for Young Engineers and
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    _BY EGBERT POMEROY WATSON_

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    Synopsis of Contents

Cleaning the boiler, removing scale, scale preventers, oil in boilers,
braces and stays, mud drums and feed pipes, boiler fittings, grate
bars and tubes, bridge walls, the slide valve, throttling engine, the
piston, testing the slide valve with relation to the ports, defects of
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    --AND--

    MANAGEMENT OF THE CORLISS ENGINE.

    BY CHARLES D. THURBER.

    _Uniform in One Volume. Cloth Cover; Price, $1.00._

    Table of Contents.

CHAPTER I.--Introductory and Historical; Steam Jacketing. CHAPTER
II.--Indicator Cards. CHAPTER III.--Indicator Cards continued; the
Governor. CHAPTER IV.--Valve Gear and Eccentric; Valve Setting.
CHAPTER V.--Valve Setting continued, with diagrams of same; Table for
laps of Steam Valve. CHAPTER VI.--Valve Setting continued. CHAPTER
VII.--Lubrication with diagrams for same. CHAPTER VIII.--Discussion of
the Air Pump and its Management. CHAPTER IX.--Care of Main Driving
Gears; best Lubricator for same. CHAPTER X.--Heating of Mills by
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for same. CHAPTER XII.--Foundations continued; Materials for same,
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    Third Edition, with an Appendix.


    THE SLIDE VALVE SIMPLY EXPLAINED

    BY W. J. TENNANT, ASSO. M.I.M.E.

    REVISED AND MUCH ENLARGED

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    CONTENTS OF CHAPTERS:

    I. The Simple Slide.

     II. The Eccentric a Crank. Special Model to Give Quantitative
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     III. Advance of the Eccentric.

     IV. Dead Centre. Order of Cranks. Cushioning and Lead.

     V. Expansion--Inside and Outside Lap and Lead; Advance Affected
     Thereby. Compression.

     VI. Double-Ported and Piston Valves.

     VII. The Effect of Alterations to Valve and Eccentric.

     VIII. Note on Link Motions.

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     General.

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    _144 Pages._      _Illustrated._      _12mo, Cloth, $1.00_


    THEORETICAL AND PRACTICAL
    Ammonia Refrigeration

    _A Work of Reference for Engineers and others Employed in the
    Management of Ice and Refrigeration Machinery._

    By ILTYD I. REDWOOD

    CONTENTS

B. T. U. Mechanical Equivalent of a Unit of Heat. Specific Heat.
Latent Heat. Theory of Refrigeration. Freezing, by Compressed Air.
Ammonia. Characteristics of Ammonia. The Compressor. Stuffing-Boxes.
Lubrication. Suction and Discharge Valves. Separator. Condenser-Worm,
Receiver. Refrigerator or Brine Tank. Size of Pipe and Area of Cooling
Surface. Charging the Plant with Ammonia. Jacket-Water, for
Compressor, for Separator. Quantity of Condensing Water Necessary.
Loss due to Heating of Condensed Ammonia. Cause of Variation in Excess
Pressure. Use of Condensing Pressure in Determining Loss of Ammonia by
Leakage. Cooling Directly by Ammonia. Freezing Point of Brine. Making
Brine. Specific Heat of Brine. Regulation of Brine Temperature.
Indirect Effect of Condensing Water on Brine Temperature. Directions
for Determining Refrigerating Efficiency. Equivalent of a Ton of Ice.
Compressor Measurement of Ammonia Circulated. Loss of Well-Jacketed
Compressors. Loss in Double-Acting Compressors. Distribution of
Mercury Wells. Examination of Working Parts. Indicator Diagrams.
Ammonia Figures--Effectual Displacement. Volume of Gas. Ammonia
Circulated per Twenty-Four Hours. Refrigerating Efficiency. Brine
Figures--Gallons Circulated. Pounds Circulated. Degrees Cooled. Total
Degrees Extracted. Loss due to Heating of Ammonia Gas. Loss due to
Heating of Liquid Ammonia. Calculation of the Maximum Capacity of a
Machine. Preparation of Anhydrous Ammonia. Construction of Apparatus,
etc., etc.

    150 pages, 15 illustrations, cloth, $1.00.


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    MECHANIC’S OWN BOOK,
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    PRINCIPAL CONTENTS.

    Mechanical Drawing. (13 pages).

     Casting and Founding. (31 pages).

     Forging and Finishing. (56 pages.)

     Soldering. (26 pages).

     Sheet-Metal Working. (10 pages).

     Carpentry, Woods, Tools, etc. (224 pages).

     Cabinet Making. (36 pages).

     Carving and Fretwork. (13 pages).

     Upholstery. (6 pages).

     Painting, Graining and Marbling. (28 pages).

     Staining, and Gilding. (16 pages).

     Polishing, Varnishing. (26 pages).

     Mechanical Movements. (56 pages).

     Turning and Lathe work. (30 pages).

     Masonry, Stonework, Brickwork, Concrete, etc. (45 pages).

     Plastering, Whitewashing, Paperhanging. (13 pages)

     Roofing, Glazing. (14 pages).

     Bell hanging, Gas fitting. (8 pages).

     Lighting, Ventilation, Warming. (21 pages).

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     Drains, Water Supply and Sanitation. House Construction, etc.
     Size of book 6-3/4 in. by 8-3/4.

    702 pages, half extra gilt and 1420 illustrations.





End of Project Gutenberg's Electric Gas Lighting, by Norman H. Schneider

*** END OF THE PROJECT GUTENBERG EBOOK 42073 ***