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_.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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Size 8 × 10. Scale 10 to 1 in. Price 25c. each. Per dozen, $2.50.

THE ELECTRICIAN’S SKETCHING BOOK.

Made from this paper. Scale 10 to 1 inch. Size of book 5 × 8 inches, with stiff board covers. Price, 25c. each; per dozen, $2.50.

Any quantity mailed to any part of the world on receipt of price. Or Books and Pads Assorted, per dozen, $2.50.

This paper is _not ruled_. Try it and you will find it GOOD, ACCURATE AND CHEAP.

SPON & CHAMBERLAIN, 12 Cortlandt St., NEW YORK.

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 and durability of gas engines. Proper erection of a gas engine. 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. Distribution of heat in a gas engine. Attendance on gas engines. General remarks. Gas engine oil. Cylinder lubricators. Rules as to starting and stopping a gas engine. The cleaning of a gas engine. General observations and specific examination for defects. The engine refuses to work. Non-starting of the engine. Too much pressure on the gas. Water in the exhaust pot. Difficulty in starting the engine. Irregular running. Loss of power. Weak gas mixtures. Late ignition. Cracks in air inlet. Back firing. Knocking and pounding inside of engine. Dangers and precautionary measure in handling gas engines. Precautions when opening gas valves, removing piston from cylinder, examining with light openings of gas engines. Dangers in starting, cleaning, putting on belts. =Oil Engines.= Gas engines with producer gas. Gasoline and oil engines. Concluding remarks.

120 pages, illustrated, l2mo, cloth, $1.00.

THE FIREMAN’S GUIDE

A Handbook on the Care of Boilers

_BY KARL P. DAHLSTROM, M.E._

CONTENTS OF CHAPTERS

=I. Firing and Economy of Fuel.=--Precautions before and after starting the fire, care of the fire, proper firing, draft, smoke, progress of firing, fuel on the grate, cleaning out, cleaning grate bars and ash pan, dampers, firing into two or more furnaces, dry fuel, loss of heat.

=II. Feed and Water Line.=--Feeding, the water line, false water line, defective feeding apparatus, formation of scale, gauge cocks, glass gauge, the float, safety plug, alarm whistle.

=III. Low Water and Foaming or Priming.=--Precautions when water is low, foaming, priming.

=IV. Steam Pressure.=--Steam gauge, safety valves.

=V. Cleaning and Blowing Out.=--Cleaning the boiler, to examine the state of the boiler, blowing out, refilling the boiler.

=VI. General Directions.=--How to prevent accidents, repairs, the care of the boiler when not in use, testing boilers, trimming and cleaning outside. Summary of rules. Index.

8vo, cloth, 50 cents.

HOW TO RUN Engines and Boilers

Practical Instruction for Young Engineers and Steam Users.

_BY EGBERT POMEROY WATSON_

REVISED AND ENLARGED

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 the slide valve, lap and lead, the pressure on a slide valve, stem connections to the valve, valves off their seats, valve stem guides, governors, running with the sun, eccentrics and connections, the crank pin, brass boxes, bearings on pins, adjustment of bearings, the valve and gearing, setting eccentrics, the actual operation, return crank motion, pounding, the connections, lining up engines, making joints, condensing engines, Torricelli’s vacuum, proof of atmospheric pressure, pumps, no power in a vacuum, supporting a water column by the atmosphere, starting a new plant, the highest qualities demanded.

Water tube boilers, fire tube boilers, why water tube boilers steam rapidly, torpedo boat boilers, management of water tube boilers, economy and maintenance of water tube boilers.

150 pages, illustrated, 16mo, cloth, $1.00.

THE CORLISS ENGINE.

BY JOHN T. HENTHORN.

--AND--

MANAGEMENT OF THE CORLISS ENGINE.

BY CHARLES D. THURBER.

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

Table of Contents.