Chapter 3

the left of the cut. A second wire from the same drum or pulley connects to the spring S. The winding of the two wires is shown in the separate figure of c, where it is seen that they are screwed fast to the periphery of the little drum, and are virtually continuations of each other. By the screw A the tension of the spring S is adjusted.

On the shaft of the little drum p is a pinion, which works into the teeth of the cog-wheel r. The shaft of r is extended through the dial of the instrument, and carries an index. The dial is marked off for volts; g g and h h are standards for carrying the pulleys.

570 STANDARD ELECTRICAL DICTIONARY.

The action of the instrument is as follows. The current passing through the wire heats it. This current by Ohm's law is proportional to the electro-motive force between the terminals. As it is heated it expands and as it cools contracts, definite expanding and contracting corresponding to definite potential differences. As the wire expands and contracts the block or pin c moves back and forth, thus turning the drum p and cogwheel r one way or permitting it to turn the other way under the pull of the spring S.

Fig. 345. CARDEW VOLTMETER.

In this construction for a given expansion of the wire the piece c only moves one half as much. The advantage of using a wire twice as long as would be required for the same degree of movement were the full expansion utilized is that a very thin wire can be employed. Such a wire heats and cools more readily, and hence the instrument reaches its reading more quickly or is more deadbeat, if we borrow a phraseology properly applicable only to instruments with oscillating indexes.

In the most recent instruments about thirteen feet of wire .0025 inch in diameter, and made of platinum-silver alloy is used.

571 STANDARD ELECTRICAL DICTIONARY.

If the potential difference to be measured lies between 30 and 120 volts the wire as described suffices. But to extend the range of the instrument a resistance in series is required. If such resistance is double that of the instrument wire, and remains double whether the latter is hot or cold the readings on the scale will correspond to exactly twice the number of volts. This is brought about in some instruments by the introduction in series of a duplicate wire, precisely similar to the other wire, and like it, carried around pulleys and kept stretched by a spring.

[Transcriber's note: If the series resistance is twice that of the voltmeter, the indicated voltage will be ONE THIRD of the total voltage.]

Thus whatever ratio of resistance exists between the two wires cold, it is always the same at any temperature, as they both increase in temperature at exactly the same rate. Tubes are provided to enclose the stretched wires and pulleys, which tubes are blackened.

The voltmeter is unaffected by magnetic fields, and, as its self-induction is very slight, it is much used for alternating currents. The tubes containing the wire may be three feet long.

Its disadvantages are thus summarized by Ayrton. It absorbs a good deal of energy; it cannot be constructed for small potential differences, as the wire cannot be made thicker, as it would make it more sluggish; there is vagueness in the readings near the zero point and sometimes inaccuracy in the upper part of the scale.

Volts, Lost. The volts at the terminals of a dynamo at full load fall short of their value on open circuit. The difference of the two values are termed lost volts.

Voltmeter, Electrostatic. A voltmeter based on the lines of the quadrant electrometer. It includes two sets of quadrants, each oppositely excited by one of the two parts, whose potential difference is to be determined. They attract each other against a controlling force as of gravity.

One form has the two sets poised on horizontal axes, bringing the parts so that the flat quadrants move in vertical planes.

In another form a number of quadrants are used in each set, the members of the two sets alternating with each other. One set is fixed, the others move and carry the index.

Vulcanite. Vulcanized india rubber which by high proportion of sulphur and proper vulcanization has been made hard. It is sometimes distinguished from ebonite as being comparatively light in color, often a dull red, while ebonite is black. For its electrical properties see Ebonite.

Both substances have their defects, in producing surface leakage. Washing with weak ammonia, or with dilute soda solution, followed by distilled water, is recommended for the surface, if there is any trouble with surface leakage. It may also be rubbed over with melted paraffine wax.

572 STANDARD ELECTRICAL DICTIONARY.

W. (a) A symbol or abbreviation for watt.

(b) A symbol or abbreviation for work.

(c) A symbol or abbreviation for weight.

Wall Bracket. A telegraph bracket to be attached to the external walls of buildings to which wires are attached as they come from the poles to reach converters, or for direct introduction into a building.

Wall Sockets. Sockets for incandescent lamps constructed to be attached to a wall.

Ward. Direction in a straight line; a term proposed by Prof. James Thompson. The words "backward" and "forward" indicate its scope.

Water. A compound whose molecule consists of two atoms of hydrogen and one atom of oxygen; formula, H2 O.

Its specific gravity is 1, it being the base of the system of specific gravities of solids and liquids.

If pure, it is almost a non-conductor of electricity. If any impurity is present it still presents an exceedingly high, almost immeasurable true resistance, but becomes by the presence of any impurity an electrolyte.

Water Equivalent. In a calorimeter of any kind the weight of water which would be raised as much as is the calorimeter with its contents by the addition of any given amount of heat received by the calorimeter.

Waterproof Lamp Globe. An outer globe for incandescent lamps, to protect them from water.

Watt. (a) The practical unit of electric activity, rate of work, or rate of energy. It is the rate of energy or of work represented by a current of one ampere urged by one volt electro-motive force; the volt-ampere.

It is the analogue in electricity of the horse power in mechanics; approximately, 746 watts represent one electric horse power.

Ohm's law, taken as C = E/R, gives as values for current, C and E/R, and for electro- motive force C R. In these formulas, C represents current strength, R represents resistance and E represents electro-motive force. Then a watt being the product of electro-motive force by current strength, we get the following values for rate of electric energy, of which the watt is the practical unit: (1) E2/R -- (2) C*E -- (3) C2 * R.

The equivalents of the watt vary a little according to different authorities. Ayrton gives the following equivalents: 44.25 foot pounds per minute--.7375 foot pounds per second--1/746 horse power. These values are practically accurate. Hospitalier gives .7377 foot pounds per second. Hering gives .737324 foot pounds per second, and 1000/745941 horse power.

573 STANDARD ELECTRICAL DICTIONARY.

It is equal to 1E7 ergs per second.

Synonym--Volt-ampere.

(c) It has been proposed to use the term as the unit of energy, instead of activity or rate of energy (Sir C. W. Siemens, British Association, 1882); this use has not been adopted and may be regarded as abandoned.

[Transcriber's note; Watt is a unit of POWER--energy per unit of time.]

Watt-hour. A unit of electric energy or work; one watt exerted or expended for one hour.

It is equivalent to : 866.448 gram-degrees C. (calories) 2654.4 foot lbs. 3600 watt-seconds or volt-coulombs. 60 watt-minutes.

Watt-minute. A unit of electric energy or work; one watt exerted or expended for one minute.

It is equivalent to 14.4408 gram-degrees C. (calories), 44.240 foot pounds, 60 watt seconds or volt-coulombs, 1/60 watt hour.

Watts, Apparent. The product in an alternating current dynamo of the virtual amperes by the virtual volts. To give the true watts this product must be multiplied by the cosine of the angle of lead or lag. (See Current, Wattless.)

[Transcriber's note: This is now called a volt-amp. The usual usage is KVA, or kilovolt-ampere.]

Watt-second. A unit of electric energy or work. One watt exerted or expended for one second.

It is equivalent to .24068 gram degree C. (calorie), .000955 lb. degree F., .737337 foot lbs., .0013406 horse power second (English), .0013592 horse power second (metric).

Synonym--Volt-coulomb.

Waves, Electro-magnetic. Ether waves caused by electromagnetic disturbances affecting the luminiferous ether. (See Discharge, Oscillatory--Maxwell's Theory of Light--Resonance. Electric.)

[Transcriber's note: The Michaelson-Morley experiment (1887) had already called ether into question, but quantum theory and photons are decades in the future.]

574 STANDARD ELECTRICAL DICTIONARY.

Weber. (a.) A name suggested by Clausius and Siemens to denote a magnet pole of unit strength. This use is abandoned.

(b.) It has been used to designate the unit of quantity--the coulomb. This use is abandoned.

(c.) It has been used to designate the unit of current strength the ampere. This use is abandoned.

[Transcriber's note: Definition (a) is now used. One weber of magnetic flux linked to a circuit of one turn produces an electromotive force of 1 volt if it is reduced to zero at a uniform rate in 1 second.]

Weber-meter. An ampere-meter or ammeter. The term is not used since the term "weber," indicating the ampere or coulomb, has been abandoned.

Welding, Electric. Welding metals by heat produced by electricity. The heat may be produced by a current passing through the point of junction (Elihu Thomson) or by the voltaic arc. (Benardos & Olzewski.)

Fig. 346. ELECTRIC WELDING INDUCTION COIL.

The current process is carried out by pressing together the objects to be united, while holding them in conducting clamps. A heavy current is turned on by way of the clamps and rapidly heats the metals at the junction, which is of course the point of highest resistance. As the metal softens, it is pressed together, one of the clamps being mounted with feed motion, flux is dropped on if necessary, and the metal pieces unite.

The most remarkable results are thus attained; almost all common metals can be welded, and different metals can be welded together. Tubes and other shapes can also be united. In many cases the weld is the strongest part.

575 STANDARD ELECTRICAL DICTIONARY.

The alternating current is employed. A special dynamo is sometimes used to produce it. This dynamo has two windings on the armature. One is of fine wire and is in series with the field magnets and excites them. The other is of copper bars, and connects with the welding apparatus, giving a current of high intensity but actuated by low potential.

Where the special dynamo is not used, an induction coil or transformer is used. The primary includes a large number of convolutions of relatively fine wire; the secondary may only be one turn of a large copper bar.

The cut shows in diagram an electric welding coil. P is the primary coil of a number of turns of wire; S S is the secondary, a single copper bar bent into an almost complete circle. It terminates in clamps D D for holding the bars to be welded. B C, B' C are the bars to be welded. They are pressed together by the screw J. The large coil I of iron wire surrounding the coils represents the iron core.

The real apparatus as at present constructed involves many modifications. The diagram only illustrates the principle of the apparatus.

In welding by the voltaic arc the place to be heated is made an electrode of an arc by connection with one terminal of an electric circuit. A carbon is connected to the other terminal. An arc is started by touching and withdrawal of the carbon. The heat may be used for welding, soldering, brazing, or even for perforating or dividing metal sheets.

Welding Transformer. The induction coil or transformer used in electric welding. For its general principles of construction, see Welding, Electric.

Wheatstone's Bridge. A system of connections applied to parallel circuits, including resistance coils for the purpose of measuring an unknown resistance. A single current is made to pass from A through two parallel connected branches, joining together again at C. A cross connection B D has a galvanometer or other current indicator in circuit. In any conductor through which a current is passing, the fall of potential at given points is proportional to the resistance between such points. Referring to the diagram a given fall of potential exists between A and C. The fall between A and B is to the fall between A and C as the resistance r between A and B is to the resistance r + r' between A and C. The same applies to the other branch, with the substitution of the resistances s and S' and the point D for r r' and B. Therefore, if this proportion holds, r : r' : : s : S'. No current will go through B D , and the galvanometer will be unaffected. Assume s' to be of unknown resistance, the above proportion will give it, if r, r' and s are known, or if the ratio of r to r' and the absolute value of s is known.

576 STANDARD ELECTRICAL DICTIONARY.

In use the resistances r, r', and s are made to vary as desired. To measure an unknown resistance it is introduced at S', and one of the other resistances is varied until the galvanometer is unaffected. Then the resistance of S' is determined by calculation as just explained. The artificial resistances may be resistance coils, q. v., or it is enough to have one unknown resistance at s. Then if the length of wire ABC is accurately known, the point B can be shifted along it until the balance is attained. The relative lengths A B, and B C, will then give the ratio r : r' needed for the calculation. This assumes the wire ABC to be of absolutely uniform resistance. This is the principle of the meter-bridge described below. The use of coils is the more common method and is carried out by special resistance boxes, with the connections arranged to carry out the exact principle as explained. The principle of construction and use of a resistance box of the Wheatstone bridge type, as shown in the cut, is described under Box Bridge, q. v.

FIG. 347. WHEATSTONE BRIDGE CONNECTIONS.

FIG. 348. TOP OF BOX BRIDGE.

577 STANDARD ELECTRICAL DICTIONARY.

The next cut shows the sliding form of bridge called the meter bridge, if the slide wire is a meter long or a half- or a quarter-meter bridge, etc., according to the length of this wire. It is described under Meter Bridge, q. v. Many refinements in construction and in proper proportion of resistances for given work apply to these constructions.

Synonyms--Electric Balance--Resistance Bridge--Wheatstone's Balance.

Fig. 349. METER BRIDGE.

Whirl, Electric. (a) A conductor carrying an electric current is surrounded by circular lines of force, which are sometimes termed an electric whirl.

(b) The Electric Flyer. (See Flyer, Electric.)

Wimshurst Electric Machine. An influence machine for producing high potential or static electricity.

Two circular discs of thin glass are mounted on perforated hubs or bosses of wood or ebonite. Each hub has a groove turned upon it to receive a cord. Each disc is shellacked. They are mounted on a horizontal steel spindle so as to face and to be within one-eighth of an inch of each other. On the outside of each disc sixteen or eighteen sectors of tinfoil or thin metal are cemented.

578 STANDARD ELECTRICAL DICTIONARY.

Two curved brass rods terminating in wire brushes curved into a semi-ellipse just graze the outer surfaces of the plates with their brushes. They lie in imaginary planes, passing through the axis of the spindle and at right angles from each other.

Four collecting combs are arranged horizontally on insulating supports to collect electricity from the horizontal diameters of the discs. These lie at an angle of about 45° with the other equalizing rods. Discharging rods connect with the collecting combs.

The principle of the machine is that one set of sector plates act as inductors for the other set. Its action is not perfectly understood.

It works well in damp weather, far surpassing other influence machines in this respect. On turning the handle a constant succession or stream of sparks is produced between the terminals of the discharging rods.

Windage. In a dynamo the real air gap between the armature windings and pole pieces is sometimes thus termed.

Wind, Electric. The rush of air particles from a point connected to a statically charged condenser.

Winding, Compound. A method of winding a generator or motor in which a shunt winding is used for the field magnets and in which also a second winding of the magnet is placed in series with the outer circuit. (See Winding, Series--Winding, Shunt.)

Fig. 350. CHARACTERISTIC CURVES OF SHUNT AND SERIES WINDING.

The object of compound winding is to make a self-regulating dynamo and this object is partly attained for a constant speed.

The characteristic curves of shunt and series winding are of opposite natures. The first increases in electro-motive force for resistance in the outer circuit, the latter decreases under the same conditions. If the windings are so proportioned that these conditions for each one of the two windings are equal and opposite, it is evident that the characteristic may be a straight line. This, however, it will only be at a single speed of rotation.

579 STANDARD ELECTRICAL DICTIONARY.

Winding, Disc. A winding which (S. P. Thompson) may be treated as a drum winding extended radially, the periphery corresponding to the back end of the drum. The magnet poles are generally placed so as to face the side or sides of the disc.

Winding, Lap. A method of winding disc and drum armatures. It consists in lapping back each lead of wire towards the preceding lead upon the commutator end of the armature. Thus taking the letter U as the diagrammatical representation of a turn of wire in connecting its ends to the commutator bars they are brought towards each other so as to connect with contiguous commutator bars. This carries out the principle of keeping the two members of the U moving in regions of opposite polarity of field, so that the currents induced in them shall have opposite directions, thus producing a total current in one sense through the bent wire.

Winding, Long Shunt. A system of compound winding for dynamos and motors. The field is wound in series and, in addition thereto, there is a shunt winding connected across from terminal to terminal of the machine, and which may be regarded either as a shunt to the outer circuit, or as a shunt to the series-field and armature winding. (See Winding, Short Shunt.)

Synonyms--Series and Long Shunt Winding.

Winding, Multiple. A winding of an electro-magnet, in which separate coils are wound on the core, so that one or any number may be used as desired in parallel or in series. For each coil a separate binding post should be provided.

Winding, Multipolar. Winding adapted for armatures of multi-polar dynamos or motors.

Winding, Series. A method of winding a generator or motor, in which one of the commutator-brush connections is connected to the field-magnet winding; the other end of the magnet winding connects with the outer circuit. The other armature-brush connects with the other terminal of the outer circuit.

Winding, Series and Separate Coil. A method of automatic regulation applied to alternating current dynamos.

Winding, Short Shunt. A method of compound winding for dynamos and motors. The field is wound in series, and in addition thereto there is a shunt winding connected from brush to brush only, thus paralleling the armature. (See Winding, Long Shunt.)

Synonyms--Series and Short Shunt Winding.

580 STANDARD ELECTRICAL DICTIONARY.

Winding, Shunt. A method of winding a generator or motor. Each commutator-brush has two connections. One set are the terminals of the outer circuit, the other set are the terminals of the field-magnet windings. In other words, the field-magnet windings are in shunt or in parallel with the outer circuit.

Winding, Shuttle. A method of dynamo or motor-armature winding. A single groove passes longitudinally around the core and in this the wire is continuously wound. The system is not now used. The old Siemens' H armature illustrates the principle.

Winding, Wave. A method of winding disc and drum armatures. It consists in advancing the commutator ends of the U shaped turns progressively, so that as many commutator bars intervene between any two consecutive commutator connections of the wire as there are leads of wire on the drum between consecutive leads of the wire. This is carried out with due regard to the principle that taking the letter U as the diagrammatical representation of a turn of wire, its two members must move through regions of the field of opposite polarity.

Wire Finder. A galvanometer or other instrument used for identifying the ends of a given wire in a cable containing several.

Work. When a force acts upon a body and the body moves in the direction of the force, the force does work. Hence, work is the action of a force through space against resistance.

It is generally expressed in compound units of length and weight, as foot-pounds, meaning a pound raised one foot.

Work, Electric, Unit of. The volt-coulomb, q. v., or watt-second, as it is often termed.

Working, Diode. In multiplex telegraphy the transmission of two messages, simultaneously, over one wire. (See Telegraphy, Multiple.)

Working, Contraplex. A variety of duplex telegraphy in which the messages are sent from opposite ends of the line, simultaneously, so as to be transmitted in opposite directions. (See Working, Diplex.)

Working, Diplex. In duplex telegraphy the sending of two independent messages from the same end of the line in the same direction.

581 STANDARD ELECTRICAL DICTIONARY.

Working, Double Curb. A method of working telegraph lines. When a signal is sent the line is charged. This has to be got rid of, and is an element of retardation. In double curb working it is disposed of by sending a momentary current first in the reverse, and then in the same, and finally in the reverse direction. This is found to reduce the charge to a very low point.

Working, Hexode. In multiplex telegraphy the transmission of six messages simultaneously over one wire. (See Telegraphy, Multiplex.)

Working, Pentode. In multiplex telegraphy the transmission of five messages simultaneously over one wire. (See Telegraphy, Multiplex.)

Working, Reverse Current. A method of telegraphy, in which the currents are reversed or alternated in direction.

Working, Single Curb. A simpler form of telegraph signaling than double curb working. It consists in sending a reverse current through the line for each signal by reversing the battery connection.

Working, Tetrode. In multiplex telegraphy the transmission of four messages simultaneously over the same line. (See Telegraphy, Multiplex.)

Working, Triode. In multiplex telegraphy the transmission of three messages simultaneously over the same wire. (See Telegraphy, Multiplex.)

Work, Unit of. The erg, q. v. It is the same as the unit of energy, of which work is the corelative, being equal and opposite to the energy expended in doing it. There are many other engineering units of work, as the foot-pound and foot-ton.

Yoke. In an electro-magnet, the piece of iron which connects the ends furthest from the poles of the two portions of the core on which the wire is wound.

Zamboni's Dry Pile. A voltaic pile or battery. It is made of discs of paper, silvered or tinned on one side and sprinkled on the other with binoxide of manganese. Sometimes as many as 2,000 of such couples are piled up in a glass tube and pressed together with two rods which form the terminals. They maintain a high potential difference, but having very high resistance and slight polarization capacity, give exceedingly small quantities.

Zero. (a) The origin of any scale of measurement.

(b) An infinitely small quantity or measurement.

582 STANDARD ELECTRICAL DICTIONARY.

Zero, Absolute. From several considerations it is believed that at a certain temperature the molecules of all bodies would touch each other, their kinetic motion would cease, and there would be no heat. This temperature is the absolute zero. It is put at -273° C. (-459° F.)

[Transcriber's note; The modern value is 0° Kelvin, -273.15° C, or -459.67° F. The lowest reported temperature observed is 1E-10° K.]

Zero, Potential. Conventionally, the potential of the earth. True zero potential could only exist in the surface of a body infinitely distant from other electrified bodies.

Zero, Thermometric. There are three thermometric zeros. In the Réaumur and centigrade scales, it is at the temperature of melting ice; in the Fahrenheit scale, it is 32° F. below that temperature, or corresponds to -17.78° C.

The third is the absolute zero. (See Zero, Absolute.)

Zinc. A metal; one of the elements; atomic weight, 65.1; specific gravity, 6.8 to 7.2.

microhms. Resistance at 0° C. (32° F.), per centimeter cube, 5.626 Resistance at 0° C. (32° F.), per inch cube, 2.215

Relative resistance (silver = 1), 3.741

ohms. Resistance of a wire, 1 foot long, weighing 1 grain, .5766 (a) 1 foot long, 1 millimeter diameter, 33.85 (b) 1 meter long, weighing 1 gram, .4023 (c) 1 meter long, 1 millimeter diameter, .07163

Zinc is principally used in electrical work as the positive plate in voltaic batteries.

Zincode. The terminal connecting with the zinc plate, or its equivalent in an electric circuit; the negative electrode; the kathode. A term now little used.

Zinc Sender. An apparatus used in telegraphy for sending a momentary reverse current into the line after each signal, thus counteracting retardation.

Zone, Peripolar. In medical electricity, the region surrounding the polar zone, q. v.

Zone, Polar. In medical electricity, the region surrounding the electrode applied to the human body.

583-624 INDEX.

Page A 7 Absolute 7 Absolute Calibration 97 Absolute Electric Potential 429 Absolute Electrometer 222 Absolute Galvanometer 266 Absolute Measurement 8 Absolute Potential 428 Absolute Temperature 8 Absolute Unit 554 Absolute Unit Resistance, Weber's 468 Absolute Vacuum 557 Absolute Zero 581 Abscissa 7 Abscissas, Axis of 54 Absorption, Electric 8 A. C. C. 8 Acceleration 8 Accumulator 8 Accumulator, Electrostatic 8 Accumulator, Water Dropping 9 Acetic Acid Battery 58 Acheson Effect 208 Acid, Carbonic 108 Acid, Chromic, Battery 61 Acid, Hydrochloric, Battery 66 Acid, Spent 491 Acid, Sulphuric 497 Acidometer 10 Acierage 494 Aclinic Line 10 Acoustic Telegraphy 10 Acoutemeter 10, 53 Action, Electrophoric 230 Action, Local 331 Action, Magne-crystallic 335 Action, Refreshing 454 Action, Secondary 477 Actinic Photometer 411 Actinic Rays. 11 Actinism 11 Actinometer, Electric 11 Active Electric Circuit, 123 Activity 11 Actual Horse Power 290 Adapter 11 A. D. C., 11 Adherence, Electro-magnetic 11 Adherence, Magnetic 338 Adjuster, Cord 152 Adjustment of Brushes 90 Admiralty Rules of Heating 12 AEolotropic 34 Aerial Cable 95 Aerial Conductor 12 Affinity 12 Affinity, Molecular 380 After Current,. 159 Agglomerate Leclanché Battery 66 Agir Motor 13 Agone 13 Agonic Line, 13 Air 13 Air Blast 13 Air Condenser 14 Air Field 252 Air Gaps 15 Air Line Wire 15 Air Pump, Heated 15 Air Pump, Mercurial 16 Air Pumps, Short Fall 16 Alarm, Burglar 16 Alarm, Electric 17 Alarm, Fire, Electric Automatic 257 Alarm, Fire and Heat 17 Alarm, Overflow 18 Alarm, Water Level 18 Alcohol, Electric Rectification of 18 Alignment, 18 Allotropy 18 Alloy 18 Alloy, Platinum 419 Alloy, Platinum-Silver 419 Alloys, Paillard 400 Alphabet, Telegraphic 19 Alternating 23 Alternating Current 159 Alternating Current Arc 23 Alternating Current Dynamo 193 Alternating Current Generator or Dynamo 24 Alternating Current Meter 373 Alternating Current System 23 Alternating Field 252 Alternative Current 563 Alternative Path 24 Alternatives, Voltaic 563 Alternator 24 Alternator, Constant Current 24 Alternator, Dead Point of an 177 Alternation 23 Alternation, Complete 23 Alternation, Cycle of 175 Alum Battery 58 Aluminum 24 Aluminum Battery 58 Amalgam 24 Amalgamation 25 Amber 25 American Twist Joint 309 Ammeter 26 Ammeter, Ayrton 26 Ammeter, Commutator 26 Ammeter, Cunynghame's 26 Ammeter, Eccentric Iron Disc 27 Ammeter, Electro-magnetic 27 Ammeter, Gravity 27 Ammeter, Magnetic Vane 27 Ammeter, Magnifying Spring 28 Ammeter, Permanent Magnet 28 Ammeter, Reducteur for 453 Ammeter, Solenoid 28 Ammeter, Spring 28 Ammeter, Steel Yard 28 Ammunition Hoist, Electric 29 Amperage 29 Ampere 29 Ampere- and Volt-meter Galvanometer 274 Ampere Arc 30 Ampere Balance 56 Ampere Currents 30 Ampere Feet 30 Ampere-hour 30 Amperes, Lost 30 Ampêre's Memoria Technica 30 Ampere Meters 26, 30 Ampere Meter, Balance 391 Ampere Meter, Neutral Wire 391 Ampere-minute 30 Ampere Ring 30 Ampere-second 30 Ampere's Theory of Magnetism 354 Ampere-turns 31 Ampere-turns, Primary 31 Ampere-turns, Secondary 31, 551 Ampere Windings 31 Ampérian Currents 165 Amplitude of Waves 31 Analogous Pole 31, 425 Analysis 31 Analysis, Electric 32 Analysis, Electrolytic 214 Analyzer, Electric 32 Anelectrics 32 Anelectrotonus 32 Angle of Declination 32, 177 Angle of the Polar Span 32 Angle of Inclination or Dip 33 Angle of Lag 33-318 Angle of Lead 33 Angle of Maximum Sensitiveness 479 Angle of Polar Span 423 Angle, Polar 423 Angle, Unit 554 Angular Currents 165 Angular Currents, Laws of 165 Angular Force 544 Angular Velocity 32, 559 Animal Electricity 33 Animal System, Electric Excitability of 247 Anion 33 Anisotropic 34 Annealing, Electric 34 Annular Electro-magnet 216 Annunciator 34 Annunciator Clock 35 Annunciator Clock, Electric 127 Annunciator Drop 35 Annunciator, Gravity Drop 35 Annunciator, Needle 35 Annunciator, Swinging or Pendulum 35 Anodal Diffusion 35 Anode 36 Anodic Closure Contraction 36 Anodic Duration Contraction 36 Anodic Opening Contraction 36 Anodic Reactions 36 Anomalous Magnet 335 Anti-induction Conductor 36, 145 Anti-magnetic Shield 37 Antilogous Pole, 425 Antimony 37 Anvil 37 A. O. C. 38 Aperiodic 38 Aperiodic Galvanometer 266 Apparent Coefficient of Magnetic Induction 346 Apparent Resistance 297, 462 Apparent Watts 573 Arago's Disc 88 Arc 39 Arc, Ampere 30 Arc, Compound. 39 Arc, Electric Blow-pipe 84 Arc, Metallic 39 Arc, Micrometer 39, 376 Arc, Multiple 387 Arc, Simple 39 Arc, Voltaic 39 Arc Box, Multiple 387 Arc Lamp 319 Arc Lamp, Differential 320 Arc Lamp, Double Carbon 191 Areometer 41 Areometer, Bead 41 Argyrometry 41 Arm 41 Armature 41 Armature, Bar 42 Armature, Bipolar 42 Armature Bore 42 Armature Chamber 42 Armature, Closed Coil 43 Armature Coil, or Coils 43 Armature Conductors, Lamination of 319 Armature Core 43 Armature, Cylinder 43 Armature, Cylindrical 45 Armature, Disc 43 Armature, Drum 45 Armature Factor 45 Armature, Flat Ring 45 Armature, Girder 49 Armature, H 49 Armature, Hinged 45 Armature, Hole 45 Armature, Intensity 45 Armature Interference 45 Armature, Load of 46 Armature, Multipolar 46 Armature, Neutral 46 Armature, Neutral Relay 46, 390 Armature, Non-polarized 46 Armature of Influence Machine 46 Armature of Leyden Jar or Static Condenser 46 Armature, Open Coil 46 Armature, Perforated 45 Armature, Pivoted 47 Armature Pockets 47 Armature, Polarized 47 Armature, Pole 47 Armature, Quantity 47 Armature, Radial 47 Armature Reactions 41 Armature, Revolving, Page's 47 Armature, Ring 48 Armature, Rolling 49 Armatures, Gyrostatic Action of 288 Armature, Shuttle 49 Armature, Siemens' Old 49 Armature, Spherical 49 Armature, Stranded Conductor 49 Armature, Unipolar 50, 553 Armature, Ventilation of 560 Armor of Cable 50 Arm, Rheostat 472 Arms, Proportionate 436 Arms, Ratio 437 Arms, Rocker 50-474 Arrester, Lightning 328 Arrester, Lightning, Counter-electro-motive Force 329 Arrester, Lightning, Plates 329 Arrester, Lightning, Vacuum. 329 Arrester Plate 417 Arrester, Spark 489 Arrival Curve 168 Articulate Speech 50 Artificial Carbon 106 Artificial Magnet 335 Ascending Lightning 330 Assymmetrical Resistance 462 Astatic 50 Astatic Circuit 12 Astatic Couple 157 Astatic Galvanometer 266 Astatic Needle 50 Astronomical Meridian, 372 Asymptote 51 Atmosphere 51 Atmosphere, Residual 51, 460 Atmospheric Electricity 51 Atom 52 Atomic Attraction 52 Atomic Current 160 Atomic Energy 238 Atomic Heat 52-285 Atomic Weight 53 Atomicity 52 Attracted Disc Electrometer 223 Attraction 53 Attraction, Atomic 52 Attraction, Magnetic 338 Attraction, Molar 380 Attraction, Molecular 380 Attraction and Repulsion, Electro-dynamic 211 Attraction and Repulsion, Electro-magnetic 217 Attraction and Repulsion, Electro-static 234 Attraction and Repulsion, Electro-static, Coulomb's Law of 155 Audiometer 53 Aura, Electrical 53 Aurora 53 Austral Pole 54 Autographic Telegraph 510 Automatic Circuit Breaker 121 Automatic Cut Out 175, 475 Automatic Drop 192 Automatic Electric Bell 78 Automatic Electric Fire Alarm 257 Automatic Switch 500 Automatic Telegraph 504 A. W. G., 54 Axial Couple 514 Axial Force 544 Axial Magnet 336 Axis, Electric 54 Axis, Magnetic 338 Axis of Abscissas 54 Axis of Ordinates 54, 397 Axis of X 54 Axis of Y 54, 397 Ayrton's Ammeter 26 Azimuth 54 Azimuth Circle 54 Azimuth Compass 141 Azimuth, Magnetic 338

B 55 B. A. 55 Back Electro-motive Force of Polarization 156 Back Induction 55 Back Shock or Stroke of Lightning 55 Back Stroke 55 Bagration Battery 59 Balance 55 Balance, Ampere 56 Balance Ampere Meter 391 Balance, Electric 577 Balance, Inductance 293 Balance, Plating 417 Balance, Slide 374 Balance, Thermic 85 Balance, Torsion, Coulomb's 544 Balance, Wheatstone's 577 Balata 56 Ballistic Galvanometer 567 Balloon Battery 59 B. and S. W. G. 56 Banked Battery 59 Bank of Lamps 323 B. A. Ohm 394 Barad 56 Bar, Armature 42 Bar, Bus 94 Bar Electro-magnet 217 Bar Magnet 336 Barometer 56 Bar, Omnibus 94 Bar Photometer 411 Bars, Commutator 56, 140 Bath 57 Bath, Bipolar Electric 57 Bath, Copper 152 Bath, Copper Stripping 152 Bath, Electric Head 284 Bath, Electric Shower 57 Bath, Gold 279 Bath, Gold Stripping 279 Bath, Multipolar Electric 57 Bath, Nickel 391 Bath, Plating 418 Baths, Electro-medical 222 Bath, Silver 484 Bath, Silver Stripping 484 Bath, Stripping 57 Bath, Unipolar Electric 57 Batten 57-58 Battery, Acetic Acid 58 Battery, Alum 58 Battery, Aluminum 58 Battery, Bagration 59 Battery, Balloon 59 Battery, Banked 59 Battery, Bichromate 59 Battery, Bunsen 59 Battery, Cadmium 60 Battery, Callan 60 Battery, Camacho's 60 Battery, Carré's 60 Battery, Cautery 61 Battery Cell, Element of a 237 Battery, Chloric Acid 61 Battery, Chloride of Lime 61 Battery, Chromic Acid 61 Battery, Closed Circuit 61 Battery, Column 61 Battery, d'Arsonval's 62 Battery, de la Rue .62 Battery, de la Rive's Floating 179 Battery, Dry 63 Battery, Elements of 63 Battery, Faradic 63 Battery, Ferric Chloride 63 Battery, Fuller's 63 Battery, Gas 63 Battery, Gas, Grove's 281 Battery Gauge 64 Battery, Gravity 64 Battery, Grenet 65 Battery, Grove's 65 Battery, Hydrochloric Acid 66 Battery, Lalande & Chaperon 69 Battery, Lalande-Edison 69 Battery, Lead Chloride 66 Battery, Lead Sulphate 66 Battery, Leclanché 66 Battery, Leclanché Agglomerate 66 Battery, Local 66, 831 Battery, Magnetic 338 Battery, Main 66 Battery, Marié Davy's 67 Battery, Maynooth's 67 Battery, Medical 67 Battery, Meidinger's 68 Battery, Mercury Bichromate 63 Battery Mud 68 Battery, Multiple Connected 68 Battery, Niaudet's 61 Battery, Nitric Acid 68 Battery of Dynamos 6S Battery of Leyden Jars, 68 Battery, Open Circuit 68 Battery or Pile, Thermo-electric 530 Battery, Oxide of Copper 68 Battery, Peroxide of Lead 69 Battery, Platinized Carbon 69 Battery, Plunge 69 Battery, Pneumatic 69 Battery, Primary 69, 434 Battery, Pulvermacher's Electro-medical 69 Battery, Sal Ammoniac 69 Battery, Salt, or Sea Salt 69 Battery, Sand 70 Battery, Secondary 70 Battery, Secondary, Planté's 72 Battery, Secondary, Real Efficiency of 205 Battery, Sir William Thomson's 72 Battery, Siemens and Halske's 72 Battery, Skrivanow 72 Battery, Smee's 73 Battery Solutions, Chromic Acid 73 119, 178, 192, 232, 318, 421, 542, 549 Battery, Spiral 73 Battery, Split 73 Battery, Sulphate of Mercury 67 Battery System, Universal 556 Battery, Thermo-chemical 530 Battery, Trough 73 Battery, Trouvé's Blotting Paper 73 Battery, Tyer's 74 Battery, Upward's 75 Battery, Varley's 76 Battery, Volta's 76 Battery, Voltaic or Galvanic 76 Battery Voltmeter 569 Battery, Water 77 Battery, Wollaston 78 B. A. Unit, 554 B. A. Unit of Resistance 78, 462 B. A. Volt 568 B. E. 78 Bead Areometer 41 Becquerel's Laws of Thermo-electricity 78 Beaumé Hydrometer 78 Bed-piece 78 Bell, Automatic Electric 78 Bell, Call 78, 98 Bell Call 79 Bell Call, Extension 248 Bell, Circular 79 Bell, Differentially Wound 79 Bell, Electric 79 Bell, Electro-mechanical 80 Bell, Indicating 80, 297 Bell, Magneto 80 Bell, Magneto Call 361 Bell, Night 392 Bell-shaped Magnet, 336 Bells, Relay 80, 457 Bell, Trembling 78 Bell, Vibrating. 78 Belts, Joints in 311 Bennett's Electroscope 233 Bias 80 Bias of Tongue of Polarized Relay 542 Bichromate Battery 59 Bichromate Mercury Battery 63 Bifilar Suspension 498 Bifilar Winding 81 Binary Compound 81 Binding 81 Binding Posts or Screws 81 Binnacle 81 Biology, Electro- 208 Bioscopy, Electric 82 Bipolar Armature 42 Bipolar Electric Bath 57 Bisected Coils 132 Bismuth 82 Bi-telephone 82, 524 Black, Platinum 419 Blasting, Electric 83 Bleaching, Electric 83 Block, Branch 87 Block, Cross-over 158 Block System 83 Block Wire 83 Blotting Paper Battery, Trouvé's 73 Blow-pipe 83 Blow-pipe, Electric Arc 84 Blue Magnetism 355 Bluestone 84 Blue Vitriol 562 Board, Cross-connecting 157 Board, Fuse 263 Board, Hanger 284 Board, Key 313 Board, Multiple Switch 387 Board of Trade Ohm 394 Board of Trade Unit 555 Board, Switch 500 Boat, Electric 84 Bobbins 84 Body Protector 84 Bohenberger's Electroscope 233 Boiler Feed, Electric 84 Boiling 84 Boll 85 Bolometer 85 Bombardment, Molecular 380 Bore, Armature 42 Boreal Pole 85 Bot 85 Bound Charge 115 Box Bridge 85 Box, Cable 95 Box, Cooling 151 Box, Distributing 190 Boxes, Flush 258 Box, Fishing 311 Box, Fuse 263 Boxing the Compass 86 Box, Junction 311 Box, Multiple Arc 387 Box, Resistance 462 Box, Resistance, Sliding 463 Box Sounding Relay 457 Box, Splice 492 Bracket, Saddle 475 Bracket, Wall 572 Braid, Tubular 550 Brake, Electro-magnetic 86 Brake, Magneto-electric 362 Brake, Prony 435 Branch 87 Branch Block 87 Branch Circuit 121 Branch Conductor 87 Branding, Electric 87 Brassing 87 Brazing, Electric 87 Break 88 Break, Circuit Loop 125 Break-down Switch 88 Breaker, Automatic Circuit 121 Breaker, Circuit 121 Breaker, Circuit, File 121 Breaker, Contact 121, 146 Break Induced Current 162 Breaking Weight 89 Break, Loop 332 Break Shock 482 Breath Figures, Electric 89 Breeze, Electric 89 Breeze, Static 493 Breguet Unit of Resistance 463 Bridge 89 Bridge, Box 89 Bridge, Inductance 293 Bridge, Induction 293 Bridge Key 313 Bridge, Magnetic 338 Bridge, Meter 373 Bridge, Resistance 577 Bridge, Reversible 472 Bridge, Slide 374 Bridge, Wheatstone . 575 Bridge, Wheatstone, Commercial 36 British Association Bridge 89 Britannia Joint 309 Broadside Method 89 Broken Circuit 125 Bronzing 89 Brush 90 Brush, Carbon 90 Brush, Collecting 90 Brush, Discharge 187 Brushes, Adjustment of 90 Brushes, Lead of 90 Brushes, Negative Lead of 324 Brushes, Scratch 476 Brush, Faradic 251 Brush Holders 91 Brush, Pilot 91 Brush, Rotating 91 Brush, Third 91 Brush Trimmer 549 Brush, Wire Gauge 92 Buckling 92 Bug 92 Bug Trap 92 Bunched Cable 95 Bunsen Battery 59 Bunsen Disc 92 Bunsen's Photometer 412 Buoy, Electric 93 Burglar Alarm 16 Burner, Electric Gas 93 Burning 94 Bus Bar 94 Bus Rod 94 Bus Wire 94 Butt Joint 310 Button, Call 98 Button, Press 94 Button, Push 93, 98 Buzzer 94 B. W. G. 94

C 95 C. C. 109 Cable 95 Cable, Aerial 95 Cable, Armature of 50 Cable, Armor of 50 Cable Box 95 Cable, Bunched 95 Cable, Capacity of 95 Cable Clip 97 Cable Core 96 Cable, Duplex 96 Cable, Flat 96 Cablegram 96 Cable Grip 96 Cable Hanger 96 Cable Hanger Tongs 97 Cable, Suspension Wire of 97 Cable Tank 97 Cadmium Battery 60 Calamine 97 Cal Electricity 208 Calibration 97 Calibration, Absolute 97 Calibration, Invariable 97 Calibration, Relative 98 Call Bell 78, 79, 98 Call Bell, Extension 248 Call Bell, Magneto 361 Call Button 98 Call, Thermo 530 Call, Thermo-electric 531 Callan Battery 60 Calling Drop 98 Calorie or Calory 98 Calorimeter 98 Calorimetric Photometer 412 Calory or Calorie 98 Cam, Listening 330 Camacho's Battery 60 Candle 99 Candle, Concentric 99 Candle, Debrun 99 Candle, Decimal 99 Candle, Electric 99 Candle-foot 259 Candle, German Standard 99 Candle Holder 99 Candle, Jablochkoff 100 Candle, Jamin 100 Candle, Meter 374 Candle Power 100 Candle Power, Nominal 101 Candle Power, Rated 101 Candle Power, Spherical 101 Candle, Standard 101 Candle, Wilde 101 Caoutchouc 101 Cap, Insulator 306 Capacity, Carrying 108 Capacity, Dielectric 102 Capacity, Electric or Electrostatic 102 Capacity, Instantaneous 102 Capacity, Magnetic Inductive 346, 349 Capillarity, Electro- 209 Capillary Electrometer 224 Capacity of a Telegraph Conductor 103 Capacity of Cable 95 Capacity of Polarization of a Voltaic Cell 103 Capacity, Polarization 424 Capacity, Residual 103 Capacity, Specific Inductive 103 Capacity, Storage 105, 495 Capacity, Unit of 105 Capillarity 105 Capillary Telephone 525 Carbon 106 Carbon, Artificial 106 Carbon Brush 90 Carbon, Concentric 107 Carbon, Cored 107 Carbon Dioxide 107 Carbon Holders 107 Carbonic Acid, 108 Carbonic Acid Gas 108 Carbonization 107 Carbonized Cloth 107 Carbon, Platinized, Battery 69 Carbon Resistance 463 Carbon, Retort 471 Carbons, Lamp, Flashing of Incandescent 257 Carbon, Telephone 525 Carbon Transmitter 549 Carbon, Volatilization of 108 Carburetted Hydrogen, Heavy 397 Carcel 108 Carcel Gas Jet 108 Carcel Lamp 108 Card, Compass 142 Cardew Voltmeter 569 Carré's Battery 60 Carrying Capacity 108 Cascade 108 Cascade, Charging and Discharging Leyden Jars in 108 Cascade, Gassiot's 275 Case-hardening, Electric 109 Cataphoresis 109 Catch, Safety 175 Cathode, etc. See Kathode 312 Caustry, Galvano 109 Cautery Battery 61 Cautery, Electric 109 Cautery, Galvano 109 Cautery, Galvano-electric 109 Cautery, Galvano-thermal 109 Cell, Battery, Element of a 237 Cell, Constant 109 Cell, Electrolytic 109 Cell, Porous 427 Cell, Selenium 478 Cell, Standard Voltaic 109 Cell, Standard Voltaic, Daniells' 109 Cell, Standard Voltaic, Latimer Clark's 110 Central Station 493 Central Station Distribution or Supply 112 Centre of Gravity 112 Centre of Gyration 112 Centre of Oscillation 112 Centre of Percussion 112 Centrifugal Force 112 Centrifugal Governor 113 C. G. S. 113 Chain, Molecular 380 Chamber, Armature 42 Chamber of Incandescent Lamp 113 Change, Chemical 116 Changer, Pole 425 Changing Over Switch 500 Changing Switch 500 Chaperon, Lalande &, Battery 69 Characteristic 169 Characteristic Curve 113, 168 Characteristic Curve, External 171 Characteristic Curve of Converter 169 Characteristic, Drooping 114 Characteristic, External 114 Characteristic, Internal 114 Characteristics of Sound 114 Charge 114 Charge and Discharge Key 313 Charge, Bound 115 Charge Current 160 Charge, Density of 115, 180 Charge, Dissipation of 115 Charge, Distribution of 115 Charge, Free 115 Charge, Negative 389 Charge, Residual 116 Charging Curve 170 Chatterton's Compound 116 Chemical Change 116 Chemical Electric Meter 375 Chemical, Electro-, Equivalents 244 Chemical Element 236 Chemical Energy 239 Chemical Equivalent 244 Chemical, Cautery Galvano 265 Chemical Recorder 117 Chemical Telephone 526 Chemical Equivalent, Thermo- 245 Chemistry 118 Chemistry, Electro- 209 Cheval, Force de 260 Chicle 56 Chimes, Electric 118 Chloric Acid Battery 61 Chloride, Ferric, Battery 63 Chloride, Lead, Battery 66 Chloride of Lime Battery 61 Chlorimeter 73 Choking Coil 132 Chronograph, Electric 118 Chromic Acid Battery 61 Chromic Acid Battery Solutions 73 Chromoscope 119 Chutaux's Solution 119 Cipher Code 130 Circle, Azimuth 54 Circle, Delezenne's 133 Circle, Galvanic or Voltaic 119 Circle, Magic 119 Circuit 120 Circuit, Astatic 120 Circuit, Branch 121 Circuit Breaker 121 Circuit Breaker, Automatic 121 Circuit Breaker, File 121 Circuit Breaker, Mercury 121 Circuit Breaker, Pendulum 121 Circuit Breaker, Tuning-fork 121 Circuit, Broken 125 Circuit Changing Switch 500 Circuit, Closed, Battery 61 Circuit, Derivative 123 Circuit, Derived 123 Circuit, Electrostatic 123 Circuit, Electric, Active 123 Circuit, External 123 Circuit, Grounded 123 Circuit, Incomplete 125 Circuit Indicator 298 Circuit Induction, Open 303 Circuit, Leg of 325 Circuit, Local 331 Circuit, Loop 125 Circuit, Loop Break 125 Circuit, Magnetic 340 Circuit, Magnetic Double 340 Circuit, Main 125 Circuit, Main Battery 125 Circuit, Metallic 125 Circuit, Negative Side of 125 Circuit, Open 125 Circuit, Positive Side of 125 Circuit, Recoil 125 Circuit, Return 125 Circuits, Forked 126 Circuit, Short 482 Circuit, Shunt 123, 126 Circuit, Simple 126 Circuits, Parallel 123, 126 Circuit, Voltaic 126 Circuit Working, Short 482 Circular Bell, 79 Circular Current, 160 Circular, Mil 379 Circular Units 126, 555 Circumflux 126 Clamp 126 Clark's Compound 126 Cleansing, Fire 257 Clearance Space, 489 Cleat, Crossing 127 Cleats 127 Cleavage, Electrification by 127 Clip, Cable 97 Clock, Annunciator 35 Clock, Controlled 127 Clock, Controlling 127 Clock, Electric Annunciator 127 Clock, Electrolytic 128 Clock, Master 127 Clock, Secondary 127 Clock, Self-winding, Electric 128 Clockwork Feed 128 Cloisons 128 Closed Circuit Battery 61 Closed Coil Armature 43 Closure 128 Closure Contraction, Kathodic 312 Cloth, Carbonized 107 Club-foot Electro-magnet 217 Clutch 128 Clutch, Electro-magnetic 128 Coatings of a Condenser, or Prime Conductor 129 Cockburn Fuse 263 Code, Cipher 130 Code, S. N. 486 Code, Telegraphic 130, 511 Coefficient 130 Coefficient, Apparent, of Magnetic Induction 346 Coefficient, Economic 130, 204, 205 Coefficient of Electrical Energy 205 Coefficient of Expansion 247 Coefficient of Induced Magnetization 359, 354 Coefficient of Magnetic Induction 346, 349 Coefficient of Mutual Induction 301 Coefficient of Self-induction 298 Coercitive Force 471 Coercive Force 471 Coercive or Coercitive Force 131 Coil and Plunger 131 Coil and Coil Plunger 131 Coil and Plunger, Differential 132 Coil, Armature 43 Coil, Choking 132 Coil, Earth 133 Coil, Electric 133 Coil, Exploring 350 Coil, Flat 133 Coil, Induction 133 Coil, Induction, Inverted 136 Coil, Induction, Telephone 137 Coil. Kicking 132 Coil, Magnet 336 Coil, Magnetizing 137 Coil, Reaction 132 Coil, Resistance 137 Coil, Resistance, Standard 464 Coil, Rhumkorff 138 Coil, Ribbon 138 Coils, Bisected 132 Coils, Compensating 138 Coils, Sectioned 138 Coils, Henry's 138 Coils, Idle 295 Coil, Single, Dynamo 202 Coil, Spark 489 Coil, Sucking 132 Collecting Brush 90 Collecting Ring 139 Collector 139 Colombin, 139 Colophony 460 Colors of Secondary Plates 478 Column Battery 61 Column, Electric 139 Comb 140 Combined Resistance 464 Comb Protector 437 Commercial Efficiency 204 Commercial Efficiency of Dynamo 195 Commercial Wheatstone Bridge 86 Common Reservoir 460 Communicator 140 Commutation, Diameter of 182 Commutator 140 Commutator Ammeter 26 Commutator Bars 140, 56 Commutator, Flats in 140 Commutator, High Bars of 289 Commutator, Neutral Line of 390 Commutator, Neutral Point of 390 Commutator of Current Generators and Motors 140 Commutators, Bars of 56 Commutator Segments 56 Commutator, Split Ring 141 Commuted Current 160 Commuter 140 Commuting Transformer 547 Compass 141 Compass, Azimuth 141 Compass, Boxing the 86 Compass Card, 142 Compass, Declination 142 Compass, Inclination 142 Compass, Mariners' 142 Compass, Points of the 143 Compass, Spirit 143 Compass, Surveyors 143 Compass, Variation of the 32, 558 Compensating Coils 138 Compensating Magnet 336 Compensating Poles 426 Compensating Resistance 144 Complementary Distribution 144 Complete Alternation 23 Component 144 Components of Earth's Magnetism 356 Composition of Forces 260 Compound Arc 39 Compound, Binary 81 Compound, Chatterton's 116 Compound, Clark's 126 Compound Dynamo 195 Compounding, Over- 399 Compound Magnet 336 Compound or Compound Wound Motor 382 Compound Winding 578 Concentration of Ores, Magnetic 340 Concentrator, Magnetic 340 Concentric Candle 99 Concentric Carbon 107 Condenser 144 Condenser, Coatings of a, or Prime Conductor 129 Condenser, Epinus' 242 Condenser, Plate 417 Condenser, Sliding 144 Condenser, Varley's 559 Condensing Electroscope 233 Conductance 144 Conductance, Magnetic 340 Conduction 144 Conduction, Electrolytic 215 Conductive Discharge 187 Conductivity 144 Conductivity, Magnetic 340 Conductivity, Specific 145 Conductivity, Unit of 145 Conductivity, Variable 145 Conductor 145 Conductor, Anti-induction 145 Conductor, Branch 87 Conductor, Capacity of a Telegraph 103 Conductor, Conical 145 Conductor, Imbricated 146 Conductor, Interpolar 307 Conductor, Leakage 325 Conductor, Prime 146, 434 Conductors, Equivalent 146 Conductors, Lamination of Armature 319 Conductors, Service 481 Conductor, Underground 552 Congress Ohm 395 Congress Volt 568 Conical Conductor 145 Conjugate 146 Connect 146 Connection, Cross 158 Connection, Relay 457 Connector 146 Consequent Points 422 Consequent Poles 146, 478 Conservation of Electricity 146 Conservation of Energy 239 Constant Current 160 Constant Current Alternator 24 Constant Current Regulation 454 Constant, Dielectric 183 Constant, Galvanometer 268 Constant Potential 429 Constant Potential Regulation 455 Constant, Time 54l Contact Breaker 121, 146 Contact, Electric 147 Contact Electricity 147 Contact Faults 147 Contact Key, Double 314 Contact Key, Sliding 316 Contact Lamp 320 Contact, Line of 330 Contact Point 147 Contact Potential Difference 147 Contact Ring 473 Contact Spring 148 Contact Series 147 Contact Theory 148 Continuity, Magnetic 340 Continuous Alternating Transformer 547 Continuous Current 161 Continuous Current Transformer 384, 547 Contraction, Anodic Closure 36 Contraction, Anodic Duration 36 Contraction, Anodic Opening 36 Contraction, Kathodic Closure 312 Contraction, Kathodic Duration 312 Contractures 148 Contraplex Working 580 Control, Electro-magnetic 218 Control, Gravity 281 Controlled Clock, 127 Controlling Clock 127 Controlling Field 148 Controlling Force 148 Controlling Magnet 185, 336 Control, Magnetic 341 Control, Spring 492 Convection, Electric 149 Convection, Electrolytic 149, 214 Convection of Heat, Electric 149 Convective Discharge 187 Conversion, Efficiency of 205 Converter 149 Cooling Box 151 Co-ordinates, Origin of 391 Co-ordinates, System of 150 Copper 151 Copper Bath 152 Copper Stripping Bath 152 Copper Voltameter 563 Cord Adjuster 152 Cord, Flexible 152 Cord, Pendant 405 Core 152 Core, Armature 43 Core, Cable 96 Cored Carbon 107 Core-discs 152 Core-discs, Perforated 154 Core-discs, Pierced 152 Core-discs, Toothed 154 Core, Laminated 154 Core, Magnet 336 Core Ratio 154 Core, Ribbon 154 Core, Ring 155 Cores, Krizik's 318 Core, Stranded 155 Core, Tangentially Laminated 155 Core Transformer 155 Core, Tubular 155 Corpusants 155 Corresponding Points 422 Coulomb 155 Coulomb's Law of Electrostatic Attraction and Repulsion 155 Coulomb's Law of Magnetic Attraction and Repulsion 338 Coulomb's Torsion Balance 544 Coulomb, Volt- 568 Counter, Electric 156 Counter Electro-motive Force 156, 228 Counter-electro-motive Force Lightning Arrester 329 Counter Inductive Effect 204 Couple 156 Couple, Astatic 157 Couple, Axial 544 Couple, Magnetic 341 Couple, Moment of 544 Couple, Thermo-electric 532 Couple, Voltaic or Galvanic 156 Coupling 259 Coupling of Dynamo 201 C. P. 157 Crater 157 Creep, Diffusion 184 Creeping 157 Creeping, Magnetic 341 Creeping of Magnetism 356 Crith 157 Critical Current 161 Critical Distance of Alternative Path 190 Critical Resistance 464 Critical Speed 157 Critical Value, Villari's 561 Crookes' Dark Space 489 Cross 157 Cross-connecting Board 157 Cross Connection 158 Cross Induction 298 Crossing Cleat 127 Crossing Wires 158 Cross-magnetizing Effect 158, 298 Cross-over Block 158 Cross, Peltier's 405 Cross Talk 158 Crucible, Electric 158 Crystallization, Electric 158 Cube, Faraday's 249 Culture. Electro- 209 Cunynghame's Ammeter 26 Cup, Mercury 371 Cup, Porous 159, 426 Current 159 Current, After 159 Current, Alternating 159 Current, Alternating System 23 Current, Alternative 563 Current Arc, Alternating 23 Current, Atomic 160 Current, Break Induced 162 Current, Charge 160 Current, Circular 160 Current, Commuted 160 Current, Constant 160 Current, Continuous 161 Current, Continuous, Transformer 384 Current, Critical 161 Current, Daniel 161 Current, U. S. or Siemens' Unit 161 Current, Demarcation 161 Current Density 161 Current, Derived 164 Current, Diacritical 161 Current, Diaphragm 161 Current, Direct 162 Current, Direct Induced 162 Current, Direction of 162 Current, Displacement 162 Current, Extra 162 Current, Faradic 162 Current, Field of Force of a 255 Current, Foucault 163 Current, Franklinic 163 Current Generator 277 Current, Induced 163 Current Induction 163 Current Induction, Unipolar 553 Current Intensity 163 Current, Inverse Induced 163 Current, Jacobi's Unit of 163 Current, Joint 163 Current, Linear 164 Current, Make and Break 164, 367 Current, Make Induced 163 Current Meter 164, 375 Current Meter, Alternating 373 Current, Negative 164 Current, Nerve and Muscle 164 Current, Opposed 164 Current, Partial 164 Current, Polarizing 164 Current, Positive 164 Current, Power of Periodic 433 Current, Pulsatory 164 Current, Rectified 164 Current, Rectilinear 165 Current, Redressed 165 Current Regulation, Constant 454 Current, Reverse Induced 163 Current Reverser 165 Currents, Ampere 30 Currents, Ampérian 165 Currents, Angular. 165 Currents, Angular, Laws of 165 Currents, Earth 166 Current, Secondary 166 Current, Secretion 166 Currents, Eddy 163 Currents, Eddy Displacement 162 Currents in Parallel Circuits, Independence of 297 Current, Sinuous 166 Current, Sheet 166 Current, Shuttle 483 Currents, Local 163 Currents, Local 331 Currents, Multiphase 166 Currents, Natural 166, 389 Currents, Nerve 390 Currents of Motion 167 Currents of Rest 167 Currents, Orders of 167 Currents, Parasitical 163 Currents, Polyphase 167 Currents, Rotatory 167 Currents, Thermo-electric 167 Current Streamlets 495 Current, Swelling 167 Current, Tailing 501 Current, Undulatory 167 Current, Unit 167 Current, Wattless 168 Curve, Arrival 168 Curve, Characteristic 113, 168 Curve, Characteristic, of Converter 169 Curve, Charging 170 Curve, Discharging 170 Curve, Elastic 206 Curve, Electro-motive Force 170 Curve, External Characteristic . 171 Curve, Harmonic 174, 485 Curve, Horse Power 171 Curve, Isochasmen 171 Curve, Life 171 Curve, Load 172 Curve, Magnetization 172 Curve of Distribution of Potential in Armature 172 Curve of Dynamo 173 Curve of Saturation of Magnetic Circuit 174 Curve of Sines 173, 485 Curve of Torque 174 Curve, Permeability Temperature 174 Curve, Sine 174, 485 Curve, Sinusoidal 174, 485 Curves, Magnetic 341 Cut In 174 Cut Out 174 Cut Out, Automatic 175, 475 Cut Out, Magnetic 175 Cut Out, Plug 175 Cut Out, Safety 175 Cut Out, Spring Jack 493 Cut Outs, Time 541 Cut Out, Wedge 175 Cutting of Lines of Force 175 Cycle of Alternation 175 Cycle of Magnetization 360 Cylinder, Armature 43 Cylinder, Electric Machine 333 Cylindrical Armature 45 Cystoscopy 175

Damper 176 Damping 176 Damping Magnet 336 Daniell's Standard Voltaic Cell 109 Dark Space, Faraday's 249 D'Arsonval's Battery 62 Dash-pot 176 Dead Beat 38, 176 Dead Beat Discharge 187 Dead Earth 176, 203 Dead Point of an Alternator 177 Dead Turns 177 Dead Turns of a Dynamo 551 Dead Wire 177 Death, Electrical 177 Debrun Candle 99 Decalescence 177 Decay of Magnetism 356 Deci 177 Decimal Candle 99 Declination, Angle of 32-177 Declination Compass 142 Declination, Magnetic 342 Declination Map 309 Declination of the Magnetic Needle 178 Decomposition 178 Decomposition, Electrolytic 178 Decrement 178 De-energize 178 Deflagration 178 Deflagrator, Hare's 73 Deflecting Field 178 Deflection 178 Deflection Method 178 Deflection of Magnet 337 Degeneration, Reaction of 179 Degradation of Energy 239 Deka 179 De la Rive's Floating Battery 179 De la Rue Battery 62 Delaurier's Solution 179 Delezenne's Circle 133 Demarcation Current 161 Demagnetization 179 Density, Current 161 Density, Electrical 115 Density, Electric Superficial 180 Density, Field 252 Density, Magnetic 342 Density of Charge 115, 180 Dental Mallet, Electric 180 Deposit, Electrolytic 180 Deposit, Nodular 392 Depolarization 180 Depolarizing Fluid 258 Derivation, Points of 180, 423 Derivative Circuit 123 Derived Circuit 123 Derived Current 164 Derived Units 555 Desk Push 180 Detector 180 Detector, Lineman's 180 Deviation of Discharge 188 Deviation, Quadrantal 180 Deviation, Semi-circular 181 Device, Safety 475 Dextrotorsal 181 Diacritical 181 Diacritical Current 161 Diagometer 181 Diagnosis, Electro- 181, 210 Diagram, Thermo-electric 532 Dial Telegraph 505 Diamagnetic 181 Diamagnetic Polarity 181, 423 Diamagnetism 182 Diameter of Commutation 182 Diapason, Electric 182 Diaphragm 182 Diaphragm Current 161 Dielectric, 182 Dielectric Capacity 102 Dielectric Constant 183 Dielectric, Energy of 183 Dielectric Polarization 183 Dielectric Resistance 183, 464 Dielectric Strain 183 Dielectric Strength 183 Dielectric Stress 496 Differential Arc Lamp 320 Differential Coil and Plunger 132 Differential Galvanometer 268 Differentially Wound Bell, 79 Differential Magnetometer 365 Differential Motor 382 Differential Relay 457 Differential Thermo-electric Pile 533 Differential Winding Working 183 Diffusion 184 Diffusion, Anodal . 35 Diffusion Creep 184 Digney Unit of Resistance 464 Dimensions and Theory of Dimensions 184 Dimmer 185 Diode Working 580 Dioxide, Carbon 107 Dioxide, Sulphur 497 Dip, Magnetic 342, 346 Dip of Magnetic Needle 185 Dipping 185 Dipping Needle 185 Direct Current 162 Direct Current Dynamo 197 Direct Induced Current, . 162 Direct Reading Galvanometer 269 Directing Magnet 185 Direction 185 Direction of Current 162 Direction, Positive 428 Directive Power 187 Disc, Arago's 38 Disc, Armature 43 Disc, Bunsen 92 Disc, Dynamo 197 Disc, Faraday's 249 Discharge and Charge Key 313 Discharge, Brush 187 Discharge, Conductive 187 Discharge, Convective 187 Discharge, Dead Beat 187 Discharge, Disruptive 187 Discharge, Duration of 188 Discharge, Glow 187 Discharge, Impulsive 188 Discharge Key, Kempe's 315 Discharge, Lateral 188 Discharge of Magnetism 356 Discharge, Oscillatory 188 Discharger 188 Discharger, Henley's Universal 189 Discharger, Universal 189 Discharger, Universal, Henley's 189 Discharge, Silent 187, 189, 206 Discharge, Spark 189 Discharge, Surging 188 Discharging Curve 170 Discharging Rod 189 Discharging Tongs 189 Disconnection 189 Discontinuity, Magnetic 342 Discovery, Oerstedt's 394 Disc Winding 579 Dispersion Photometer 412 Displacement Current 162 Displacement, Electric 188 Displacement, Oscillatory 398 Disruptive Discharge 187 Disruptive Tension 189 Dissimulated Electricity 189 Dissipation of Charge 115 Dissociation 189, 535 Distance, Critical, of Alternative Path 190 Distance, Explosive 190 Distance, Sparking 190 Distance, Striking 496 Distant Station 493 Distillation 190 Distortion of Field 252 Distributing Box 190 Distributing Switches 190 Distribution, Complementary 144 Distribution, Isolated 309 Distribution of Charge 115 Distribution of Electric Energy, Systems of 190 Distribution of Magnetism, Lamellar, 357 Distribution of Magnetism, Solenoidal 358 Distribution of Supply, Central Station 112 Door Opener, Electric 190 Dosage, Galvanic 190 Double Break Switch 500 Double Carbon Arc Lamp 191 Double Contact Key 314 Double Curb Working 581 Double Fluid Theory 191 Double Fluid Voltaic Cell 191 Double Magnetic Circuit 340 Double Needle Telegraph 506 Double Plug 191 Double Pole Switch 500 Double Tapper Key 314 Double Touch, Magnetization by 358 Double Trolley 549 Double Wedge 191 Doubler 191 D. P. 191 Drag 191 Drag of Field 254 Dreh-Strom 191 Drill, Electric 191 Drip Loop 192 Driving Horns 192 Dronier's Salt 192 Drooping Characteristic 114 Drop, Annunciator 35 Drop, Automatic 192 Drop, Calling 98 Drum Armature 45 Drum, Electric 193 Dry Battery 63 Dry Pile, Zamboni's 581 Dub's Laws 193 Duct 193 Duplex Bridge Telegraph 506 Duplex Cable 96 Duplex Differential Telegraph 507 Duplex Telegraph, 506 Duration Contraction, Kathodic 312 Duration of Electric Spark 490 Dyad 193 Dyeing, Electric 193 Dynamic Electricity 193 Dynamic, Electro- 211 Dynamic Induction, Magnetic 347 Dynamo, Alternating Current 193 Dynamo, Alternating Current Regulation of 195 Dynamos, Battery of 68 Dynamo, Commercial Efficiency of 195 Dynamo, Compound 195 Dynamo, Coupling of 201 Dynamo, Curve of 173 Dynamo, Dead Turns of a 551 Dynamo, Direct Current 197 Dynamo, Disc 197 Dynamo-electric Machine 197 Dynamo, Electroplating 198 Dynamo, Equalizing 198 Dynamo, Field and Armature Reaction of 450 Dynamo, Far Leading 198 Dynamo or Magneto-electric Generator, Flashing in a 257 Dynamo, Inductor 199 Dynamo, Interior Pole 199 Dynamo, Iron Clad 200 Dynamo, Ironwork Fault of a 308 Dynamo, Motor 200 Dynamo, Multipolar 200 Dynamo, Non-polar 200 Dynamo, Open Coil 200 Dynamo, Overtype 399 Dynamos, Regulation of 455 Dynamo, Ring 200 Dynamo, Self Exciting 201 Dynamo, Separate Circuit 201 Dynamo, Separately Excited 201, 479 Dynamo, Series 201 Dynamo, Shunt 202 Dynamo, Single Coil 202 Dynamo, Tuning Fork 202 Dynamo, Unipolar 202, 553 Dynamograph 199 Dynamometer 200 Dyne 203

Earth 203 Earth Coil 133 Earth Currents 166 Earth, Dead 176, 203 Earth, Magnetization by 359 Earth, Partial 203, 404 Earth Plate 203 Earth Return 203 Earth's Magnetism, Components of 356 Earth, Solid 203 Earth, Swinging 203 Earth, Total 203 Ebonite 203 Eccentric Iron Disc Ammeter 27 Economic Coefficient 130, 204, 205 Eddy Currents 163 Eddy Displacement Currents 162 Ediswan 204 Edison Effect 204 Edison-Lalande Battery 69 Eel, Electric 204 Effect, Acheson 208 Effect, Counter-inductive 204 Effect, Cross-magnetizing 158, 298 Effect, Edison 204 Effect, Faraday 249 Effect, Ferranti 251 Effect, Hall 284 Effect, Joule 311 Effect, Kerr 235, 312 Effect, Mordey 381 Effect, Page 401 Effect, Peltier 404 Effect, Photo-voltaic 415 Effect, Seebeck 478 Effect, Skin 486 Effect, Thomson 538 Effect, Voltaic 563 Efficiency 204 Efficiency, Commercial 204 Efficiency, Electrical 205 Efficiency, Gross 205 Efficiency, Intrinsic 205 Efficiency, Net 205 Efficiency of Conversion 205 Efficiency of Secondary Battery Quantity 205 Efficiency of Secondary Battery, Real 205 Efflorescence 206 Effluvium, Electric 206 Egg, Philosopher's 409 Elastic Curve 206 Elasticity, Electric 206 Electrepeter 206 Electric, Absolute, Potential 429 Electric Absorption 8 Electric Actinometer 11 Electric Alarm 17 Electrical Classification of Elements 237 Electrically Controlled Valve 558 Electric Ammunition Hoist 29 Electric Analysis 32 Electric Analyzer 32 Electric Annealing 34 Electric Annunciator Clock 127 Electric Arc Blow-pipe 84 Electric Aura 53 Electric Automatic Fire Extinguisher 257 Electric Axis 54 Electric Balance 577 Electric Bath, Bipolar 57 Electric Bath, Multipolar 57 Electric Bath, Unipolar 57 Electric Bell 79 Electric Bell, Automatic 78 Electric Bioscopy 82 Electric Blasting 83 Electric Bleaching 83 Electric Boat 84 Electric Boiler Feed 84 Electric Branding 87 Electric Brazing 87 Electric Breath Figures 89 Electric Breeze 89 Electric Buoy 93 Electric Candle 99 Electric Case Hardening 109 Electric Cautery 109 Electric Chimes 118 Electric Chronograph 118 Electric Circuit, Active 123 Electric Clock, Self-winding 128 Electric Coil 133 Electric Column 139 Electric Contact 147 Electric Convection 149 Electric Convection of Heat 149, 286 Electric Counter 156 Electric Crucible 158 Electric Crystallization 158 Electric Death 177 Electric Density 115 Electric Dental Mallet 180 Electric Diapason 182 Electric Displacement 189 Electric Door Opener 190 Electric Double Refraction 454 Electric Drill 191 Electric Drum 193 Electric Dyeing 193 Electric Eel 204 Electric Efficiency 205 Electric Effluvium 206 Electric Elasticity 206 Electric Endosmose 238 Electric Energy 239 Electric Energy, Coefficient of 205 Electric Energy, Systems of Distribution of 190 Electric Engraving 245 Electric Entropy 242 Electric Etching 245 Electric Evaporation 246 Electric Excitability of Animal Systems 247 Electric Exosmose 247 Electric Expansion 247 Electric Fire Alarm, Automatic 257 Electric Floor Matting 369 Electric Fluid 258 Electric Fly or Flyer 259 Electric Fog 259 Electric Furnace 263 Electric Fuse 264 Electric Gas Burners 93 Electric Headlight 285 Electric Head Bath 284 Electric Heat 285 Electric Heater 286 Electric Horse Power 290 Electric Image 296 Electric Incandescence 297 Electric Influence 305 Electric Insulation 305 Electricities, Separation of 479 Electricity 206 Electricity, Animal 33 Electricity, Atmospheric 51 Electricity, Cal 208 Electricity, Conservation of 146 Electricity, Contact 147 Electricity, Dissimulated 189 Electricity, Dynamic 193 Electricity, Frictional 262 Electricity, Latent 323 Electricity, Negative 389 Electricity, Plant 317 Electricity, Positive 428 Electricity, Specific Heat of 491 Electricity, Static 493 Electricity, Storage of 495 Electricity, Voltaic 563 Electricity, Vitreous 562 Electric Machine, Plate 417 Electric Machine, Wimshurst 577 Electric Mains 367 Electric Mass 368 Electric Matter 368 Electric Meter, Chemical 375 Electric Meter, Thermal 375 Electric Meter, Time 375 Electric Mortar 382 Electric Motor 382 Electric or Electrostatic Capacity 102 Electric Organ 397 Electric Oscillations 398 Electric Osmose 398 Electric Pen 405 Electric Pendulum 405 Electric Piano 415 Electric Picture 415 Electric Pistol 416 Electric Popgun 282 Electric Portrait 415 Electric Potential Difference 429 Electric Potential, Unit of 432 Electric Power 433 Electric Pressure 434 Electric Probe 435 Electric Prostration 437 Electric Protector 437 Electric Radiometer 447 Electric Ray 450 Electric Rectification of Alcohol 18 Electric Reduction of Ores 453 Electric Reduction of Phosphorous 410 Electric Register 454 Electric Residue 116, 460 Electricity, Resinous 461 Electric Resonance 468 Electric Resonator 470 Electric Rings 392 Electrics 208 Electric Saw 476 Electric Screen, 476 Electric Shadow 480 Electric Shock 482 Electric Shower Bath 57 Electric Soldering 487 Electric Spark, Duration of 490 Electric Sphygmophone 491 Electric Storms 495 Electric Striae 496 Electric Subway 496 Electric Subway, Underground 552 Electric Sunstroke 497 Electric Superficial Density 180 Electric Swaging 499 Electric Tele-barometer 504 Electric Telemanometer 521 Electric Telemeter 521 Electric Tempering 527 Electric Tension 529 Electric Thermometer 535 Electric Thermostat 537 Electric Torpedo 543 Electric Tower 545 Electric Transmission of Energy 240 Electric Trumpet 550 Electric Tube 550 Electric Typewriter 551 Electric Unit of Work 580 Electric Varnish 559 Electric Welding 574 Electric Whirl 577 Electric Wind 578 Electrification 208 Electrification by Cleavage 127 Electrification by Pressure 434 Electrified Body, Energy of an . 241 Electrization 208 Electro-biology 208 Electro-capillarity 209 Electro-chemical Equivalents 209, 244 Electro-chemical Series 209 Electro-chemistry 209 Electro-culture 209 Electrode 210 Electrode, Indifferent 210 Electrodes, Erb's Standard of 210 Electrodes, Non-polarizable 210 Electrodes, Shovel 483 Electrode, Therapeutic 210 Electro-diagnosis 181, 210 Electro-dynamic 211 Electro-dynamic Attraction and Repulsion, 211 Electro-dynamic Rotation of Liquids 474 Electro-dynamometer, Siemens' 212 Electro-gilding 277 Electro-kinetic 211 Electrolier 212 Electrolysis 212 Electrolysis, Laws of 213 Electrolyte 214 Electrolytic Analysis 214 Electrolytic Cell 109 Electrolytic Clock 128 Electrolytic Conduction 215 Electrolytic Convection 149, 214 Electrolytic Deposit 180 Electrolytic Iron 308 Electrolytic Resistance 464 Electro-magnet 215, 337 Electro-magnet, Annular 216 Electro-magnet, Bar 217 Electro-magnet, Club-foot 217 Electro-magnet, Hinged 217 Electro-magnet, Hughes' 291 Electro-magnetic Ammeter 27 Electro-magnetic and Magnetic Equipotential Surface 244 Electro-magnetic Attraction and Repulsion 217 Electro-magnetic Brake 86 Electro-magnetic Clutch 128 Electro-magnetic Control 218 Electro-magnetic Eye 248 Electro-magnetic Field of Force 218 Electro-magnetic Force 260 Electro-magnetic Gun 282 Electro-magnetic Induction 218, 299 Electro-magnetic Inertia 305 Electro-magnetic Induction, Mutual 302 Electro-magnetic Interrupter for Tuning Fork 307 Electro-magnetic Leakage 219 Electro-magnetic Lines of Force 219 Electro-magnetic Liquids, Rotation of 475 Electro-magnetic Meter 375 Electro-magnetic Quantity 445 Electro-magnetic Quantity, Practical Unit of 445 Electro-magnetic Shunt .483 Electro-magnetic Stress 219, 496 Electro-magnetic Theory of Light 219 Electro-magnetic Unit of Energy 220 Electro-magnetic Vibrator 561 Electro-magnetic Waves, 573 Electro-magnet, Ironclad 219 Electro-magnetism 220 Electro-magnet, Joule's 337 Electro-magnet, Long Range 220 Electro-magnet, One Coil 219 Electro-magnet, Plunger 220 Electro-magnet, Polarized 220 Electro-magnets, Interlocking 221 Electro-magnets, Multiple Wire Method of Working 388 Electro-magnet, Stopped Coil 221 Electro-magnets, Surgical 222 Electro-mechanical Bell 80 Electro-mechanical Equivalent 244 Electro-medical Baths 222 Electro-medical Battery, Pulvermacher's 69 Electro-metallurgy 222 Electrometer 222 Electrometer, Absolute 222 Electrometer. Attracted Disc 223 Electrometer, Capillary 224 Electrometer Gauge 226 Electrometer, Lane's 226 Electrometer, Quadrant 226 Electrometer, Thermo- 536 Electrometer, Weight 223 Electro-motive Force 227 Electro-motive Force, Counter- 228 Electro-motive Force Curve 170 Electro-motive Force, Impressed 297 Electro-motive Force, Motor 384 Electro-motive Force. Oscillatory 398 Electro-motive Force, Transverse 549 Electro-motive Force, Unit 228 Electro-motive Intensity 228 Electro-motive Potential Difference 429 Electro-motive Series 228 Electro-motograph 229 Electro-motor 229 Electro-muscular Excitation 229 Electro-negative 229 Electro-optics 229 Electrophoric Action 230 Electrophorus 230 Electro-physiology 231 Electroplating 231, 418 Electroplating Dynamo 198 Electro-pneumatic Signals 231 Electropoion Fluid 232 Electro-positive 232 Electro-puncture 232 Electro-receptive 232 Electroscope 232 Electroscope, Bennett's 233 Electroscope, Bohenberger's 233 Electroscope, Condensing 233 Electroscope, Gold Leaf 233 Electroscope, Pith Ball 234 Electrostatic Attraction and Repulsion 234 Electrostatic Attraction and Repulsion. Coulomb's Law of 155 Electrostatic Circuit 123 Electrostatic Equipotential Surface 244 Electrostatic Field of Force 254 Electrostatic Force 260 Electrostatic Induction 302 Electrostatic Induction, Coefficient of 234 Electrostatic Induction, Mutual 303 Electrostatic Lines of Force 234 Electrostatic Quantity 445 Electrostatic Refraction 235 Electrostatics 235 Electrostatic Series 235 Electrostatic Stress 236, 496 Electrostatic Telephone 526 Electrostatic Voltmeter 571 Electro-thermal Equivalent 245 Electro-therapeutics or Therapy 236 Electrotonic State 493 Electrotonus 236 Electrotype 236 Element, Chemical 236 Element, Galvanic 264 Element, Mathematical 237 Element, Negative 390 Element of a Battery Cell 237 Element, Positive 277 Elements, Electrical Classification of 237 Elements, Magnetic 342 Elements of Battery 63 Elements, Thermo-electric 237 Element, Voltaic 237 Elias' Method of Magnetization 360 Elongation 237, 540 Elongation, Magnetic 344 Embosser, Telegraph 237 E. M. D. P. 238 E. M. F. 238 Energy 238 Energy, Atomic 238 Energy, Chemical 239 Energy, Conservation of 239 Energy, Degradation of 239 Energy, Electric 239 Energy, Electrical, Coefficient of 205 Energy, Electric Transmission of 240 Energy, Electro-magnetic, Unit of 220 Energy, Kinetic 241 Energy, Mechanical 241 Energy Meter 375 Energy, Molar 241 Energy, Molecular 241 Energy of an Electrified Body 241 Energy of Dielectric 183 Energy of Position 211 Energy of Stress 241 Energy, Physical 241 Energy, Potential, or Static 241 Energy, Radiant 446 Energy, Thermal 242 End-on Method 238 End or Pole, Marked 368 Endosmose, Electric 238 End Play 238 End, Unmarked 556 English Absolute or Foot Second Unit of Resistance 465 Engraving, Electric 245 Entropy 242 Entropy, Electric 242 Epinus Condenser 242 E. P. S. 243 Equator, Magnetic 344 Equator of Magnet 337 Equipotential 244 Equipotential Surface 498 Equipotential Surface, Electrostatic 244 Equipotential Surface, Magnetic and Electro-magnetic 244 Equalizer 243 Equalizer, Feeder 251 Equalizing Dynamo 198 Equivalent, Chemical 116, 244 Equivalent Conductors 146 Equivalent, Electro-thermal 245 Equivalent, Joule's 311 Equivalent Resistance 465 Equivalents, Electro-chemical 209, 244 Equivalent, Thermo-chemical 245 Equivalent, Water 572 Equivolt 245 Erb's Standard of Electrodes 210 Erg 245 Erg-ten 245 Error, Heating 286 Escape 245 Essential Resistance 465, 466 Etching, Electric 245 Ethene 397 Ether 246 Eudiometer 246 Evaporation, Electric 246 Ewing's Theory of Magnetism 356 Exchange, Telephone 246 Excitation, Electro-muscular 229 Excitability, Faradic 246 Excitability, Galvanic 247 Excitability of Animal System, Electric 247 Exciter 247 Exosmose, Electric 247 Expansion, Coefficient of 247 Expansion, Electric 247 Experiment, Franklin's 261 Experiment, Hall's 284 Experiment, Kerr's 312 Experiment, Matteueci's 369 Experiments, Hertz's 470 Experiment, Volta's Fundamental 567 Experiment with Frog, Galvani's 262 Exploder 247 Explorer 247 Exploring Coil 350 Explosive Distance 190 Extension Bell Call 248 Extension, Polar 423 External Characteristic 114 External Characteristic Curve 171 External Circuit 123 External Resistance 465, 467 Extinguisher, Automatic Electric Fire 257 Extra Current 162 Extra-polar Region 454 Eye, Electro-magnetic 248 Eye, Selenium 478

Facsimile Telegraph 510 Factor, Armature 45 Fahrenheit Scale 248 Fall of Potential 430 False Poles, Magnetic 350 Farad 248 Faraday, Effect 249 Faraday's Cube 249 Faraday's Dark Space 249, 489 Faraday's Disc 249 Faraday's Net 250 Faraday's Ring 473 Faraday's Transformer 250 Faraday's Voltameter 250 Faradic 250 Faradic Battery 63 Faradic Brush 251 Faradic Current 162 Faradic Excitability 246 Faradization 251 Faradization, Galvano- 265 Far Leading Dynamo 198 Fault of a Dynamo, Ironwork 308 Faults 251 Faults, Contact 147 Feed Clockwork 128 Feeder 251 Feeder, Equalizer 251 Feeder, Main or Standard 251 Feeder, Negative 251 Feeder, Neutral 251 Feeder, Positive 251 Feeder, Switch 500 Feet, Ampere 30 Ferranti Effect 251 Ferric Chloride Battery 63 Ferro-magnetic 252 Fibre and Spring Suspension 252 Fibre Suspension 252 Field, Air 252 Field, Alternating 252 Field and Armature Reaction of Dynamo, 450 Field, Controlling 148 Field, Deflecting 178 Field Density 252 Field, Distortion of 252 Field, Drag of 254 Field, Intensity of a Magnetic 306 Field Magnet 337 Field of Force . 254 Field of Force, Electro-magnetic 218 Field of Force, Electrostatic 254 Field of Force, Magnetic 344 Field of Force of a Current 255 Field of Force, Uniform 553 Field, Pulsatory 256 Field, Rotating 256 Field, Stray 256, 495 Field, Uniform 256 Field, Uniform Magnetic 345 Field, Waste 256 Figure of Merit 256 Figures, Haldat's 284 Figures, Lichtenberg's 327 Figures, Magnetic 345 Filament 256 Filament, Magnetic 345 Filaments, Paper 402 File, Circuit Breaker 121 Finder, Position 427 Finder, Range 447 Finder, Wire 580 Fire Alarm, Electric Automatic 257 Fire and Heat Alarm 17 Fire Extinguisher, Electric Automatic 257 Fire Cleansing 257 Fire, St. Elmo's 494 Fishing Box 311 Flashing in a Dynamo or Magneto-Electric Generator 257 Flashing of Incandescent Lamp Carbons 257 Flashing Over 258 Flash, Side 484 Flat Cable 96 Flat Coil 133 Flat Ring Armature 45 Flats 258 Flats in Commutator 140 Flexible Cord 152 Floating Battery, De la Rive's 179 Floating Magnets, Meyer's 370 Floor Matting, Electric 369 Floor Push 258 Fluid, Depolarizing 258 Fluid, Electric 258 Fluid, Electropoion 232 Fluid, Insulator. 306 Fluid, North Magnetic 357 Fluids, Magnetic 345 Fluid, South Magnetic 356 Fluid Theory, Single 486 Fluorescence 258 Flush Boxes 258 Fluviograph 259 Flux, Magnetic 345 Fly or Flyer, Electric 259 Foci Magnetic 259 Fog, Electric 259 Following Horns 259 Foot-candle 259 Foot, Mil- 379 Foot-pound 259 Foot-step 259 Force 259 Force, Annular 544 Force, Axial 544 Force, Centrifugal 112 Force, Coercive or Coercitive 131-471 Force, Controlling 148 Force, Counter-electro-motive 156 Force de Cheval 260 Force, Electro-magnetic 260 Force, Electro-motive 227 Force, Electro-motive, Transverse 549 Force, Electrostatic 260 Force, Field of 254 Force, Field of, of a Current 255 Force, Field of, Electrostatic 254 Force, Kapp Line of 312 Force, Lines of 330 Force, Magnetic 346 Force, Magnetic Field of 344 Force, Magnetic Lines of 348 Force, Magneto-motive 365 Force, Motor Electro-motive 384 Force of Polarization, Back Electro-motive 156 Force, Oscillatory, Electro-motive 398 Force, Photo-electro-motive 410 Forces, Composition of 260 Forces, Parallelogram of 260 Forces, Resolution of 261 Force, True Contact 549 Force, Tubes of 261 Force, Unit of 261 Forked Circuits 126 Fork, Tuning, Dynamo 202 Forming 261 Formula of Merit 256 Foucault Current 163 Foundation Ring 261 Fourth State of Matter 261 Frame 261 Frame, Resistance 465 Franklinic Current 163 Franklin's Experiment 261 Franklin's Plate 262 Franklin's Theory 262-486 Free Charge 115 Free Magnetism 356 Frequency 262 Frequency, High 289 Frictional Electricity 262 Frictional Electric Machine 333 Frictional Heating 262 Friction Gear, Magnetic 276 Friction, Magnetic 295-346 Fringe 262 Frog, Galvani's Experiment with 262 Frog, Rheoscopic 262 Frying 263 Fulgurite 263 Fuller's Battery 63 Fulminating Pane 262 Fundamental Unit 554 Furnace, Electric 263 Fuse Block 175 Fuse Board 263 Fuse Box 263 Fuse, Cockburn 263 Fuse, Electric 264 Fuse Links 330 Fuse, Safety 175-475

Galvanic 264 Galvanic Action, Volta's Law of 568 Galvanic Dosage 190 Galvanic Element 264 Galvanic Excitability 247 Galvanic or Voltaic Battery 76 Galvanic or Voltaic Circle 119 Galvanic or Voltaic Couple 156 Galvanic Polarization 265 Galvani's Experiment with Frog 262 Galvanism 265 Galvanization 265 Galvanization, Labile 265 Galvanized Iron 265 Galvano-cautery 109 Galvano-cautery, Chemical 265 Galvano-electric Cautery 109 Galvano-faradization 265 Galvanometer 265 Galvanometer, Absolute 266 Galvanometer, Aperiodic 266 Galvanometer, Astatic 266 Galvanometer, Ballistic 267 Galvanometer Constant 268 Galvanometer, Differential 268 Galvanometer, Direct Reading 269 Galvanometer, Marine 269 Galvanometer, Mirror 271 Galvanometer, Potential 269 Galvanometer, Proportional 269 Galvanometer, Quantity 269 Galvanometer, Reflecting 270 Galvanometer, Shunt 271-483 Galvanometer, Sine 271 Galvanometer, Tangent 272 Galvanometer, Torsion 273-544 Galvanometer, Upright 274 Galvanometer, Vertical 274 Galvanometer, Volt and Ampere Meter 274 Galvano-plastics 275 Galvano-puncture 232-275 Galvanoscope 275 Galvano-thermal Cautery 100 Gap, Spark 490 Gas Battery 63 Gas Battery, Grove's 281 Gas Burner, Electric 93 Gas, Carbonic Acid 108 Gas, Electrolytic 275 Gases, Magnetism of 357 Gases, Mixed 275 Gas Jet, Carcel 108 Gas, Olefiant 397 Gassing 275 Gassiot s Cascade 275 Gastroscope 275 Gas Voltameter 564 Gauge, Battery 64 Gauge, Electrometer 226 Gauss 275 Gauss' Principle 276 Gauss, Tangent Positions of 276 Gauze Brush, Wire 92 Gear, Magnetic 346 Gear, Magnetic Friction 276 Geissler Pump 437 Geissler Tubes 276 Generating Plate 277 Generator, Current 277 Generator Inductor 199 Generator, Magneto-electric 362 Generator, Magneto-electric, Flashing in a Dynamo or 257 Generator, Motor 384 Generator, Pyromagnetic. 442 Generators and Motors, Commutator of Current 140 Generator, Secondary 277-477 Geographic Meridian 372 German Mile Unit of Resistance 466 German Silver 277 German Standard Candle 99 Gilding, Electro- 277 Gilding Metal 277 Gimbals 278 Girder Armature 49 Glass 278 Globe or Globular Lightning 330 Glow Discharge 187 Gold 278 Gold Bath 279 Gold Leaf Electroscope 233 Gold Stripping Bath 279 Governor, Centrifugal 113 Governor, Rate 449 Graduator 279 Gram 280 Gram-atom 280 Gram-molecule 280 Graphite 280 Gravitation 280 Gravity, Acceleration of 280 Gravity Ammeter 27 Gravity Battery 64 Gravity, Centre of 112 Gravity Control 281 Gravity Drop Annunciator 35 Grease Spot 92 Green Vitriol 562 Grenet Battery 65 Grid 281 Grid Plug 420 Grip, Cable 96 Gross Efficiency 205 Ground 281 Grounded Circuit 123 Ground Plate 417 Ground Wire 281 Grove's Battery 65 Grove's Gas Battery 281 Guard Ring 282 Guard Tube 282 Gun, Electro-magnetic 282 Gutta Percha 282 Gyration, Centre of 112 Gyrostatic Action of Armatures 283

H 283 H Armature 49 Haarlem Magnet 337 Hair, Removal of, by Electrolysis 283 Haldat's Figures 284 Hall Effect 284 Hall Effect, Real 284 Hall Effect, Spurious 284 Halleyan Lines 308 Hall's Experiment 284 Halske's and Siemens' Battery 72 Hand Hole 190 Hanger Board 284 Hanger, Cable 96 Hanger, Cable, Tongs 97 Harcourt's Pentane Standard 406 Hare's Deflagrator 73 Harmonic 23 Harmonic Curve 174, 485 Harmonic Motion, Simple 486 Harmonic Receiver 284, 451 Head Bath, Electric 284 Head-light, Electric 285 Head, Torsion 544 Heat 285 Heat and Fire Alarm 17 Heat, Atomic 52, 285 Heat, Electric 285 Heat, Electric, Convection of 149, 286 Heat, Irreversible. 286 Heat, Mechanical Equivalent of 286 Heat, Molecular 286 Heat, Specific 286 Heat, Specific, of Electricity 288 Heat Units 288 Heater, Electric 286 Heating, Admiralty Rules of 12 Heating Error 286 Heating, Frictional 262 Heating Magnet 286 Heavy Carburetted Hydrogen, 397 Hecto 288 Hedgehog Transformer 548 Heliograph 288 Helix 288 Henley's Universal Discharger 189 Henry 288 Henry's Coils 138 Hermetically Sealed 289 Hertz's Experiments 470 Heterostatic Method 280 Hexode Working 581 High Bars of Commutator 289 High Frequency 289 High Vacuum 557 Hinged Armature 45 Hinged Electro-magnet 217 Hissing 289 Hittorf's Resistance 466 Hittorf's Solution 289 Hoffer's Method of Magnetization 360 Hole Armature 45 Hole, Hand 190 Holders 289 Holder, Brush 91 Holder, Candle 99 Holders, Carbon 107 Holophote Lamp 321 Holtz's Influence Machine 334 Home Station 493 Hood 290 Horizontal Induction 302 Horns 290 Horns, Driving 132 Horns, Following 259 Horns, Leading 324 Horns, Trailing 259 Horse Power 290 Horse Power, Actual 290 Horse Power Curve 171 Horse Power, Electric 290 Horse Power Hour 290 Horse Power, Indicated 290 Horseshoe Magnet 337 Hour, Ampere- 30 Hour, Horse Power 290 H. P. 290 Hughes' Electro-magnet 291 Hughes' Induction Balance 291 Hughes' Sonometer 488 Hughes' Telegraph 511 Hughes' Theory of Magnetism 357 Hughes' Type Printer 511 Human Body, Resistance of 467 Hydrochloric Acid Battery 66 Hydro-electric 293 Hydro-electric Machine 293 Hydrogen 294 Hydrogen, Carburetted, Heavy 397 Hydrometer, Beaumé 78 Hygrometer 294 Hyperbolic Logarithms 389 Hysteresis 295 Hysteresis, Magnetic 294 Hysteresis, Static 295 Hysteresis, Viscous 295, 356

Idioelectrics 295 Idiostatic Method 295 Idle Coils 295 Idle Poles 296 Idle Wire 291 Igniter 296 I. H P. 296 Illuminating Power 296 Illuminating Power, Spherical 296 Illuminating Power, Standard of, Viole's 561 Illumination, Unit of 296 Image, Electric 296 Imbricated Conductor 146 Immersion, Simple 185 Impedance 297, 462 Impedance, Impulsive 297 Impedance, Oscillatory 297 Impressed Electro-motive Force 297 Impulse 297 Impulsive Discharge 188 Impulsive Impedance 297 In-and-out, Soaking 486 Incandescence, Electric 297 Incandescent Lamp 321 Incandescent Lamp Carbons, Flashing of 257 Incandescent Lamp, Chamber of 113 Incandescent Lamp, Life of 327 Incandescent Lamp, Three Filament 322 Inclination Compass 142 Inclination, Magnetic 346 Inclination Map 297 Inclination or Dip, Angle of 33 Incomplete Circuit 125 Increment Key 314 Independence of Currents in Parallel Circuits 297 India Rubber 102 Indicated Horse Power 290 Indicating Bell 80, 297 Indicator 298 Indicator, Circuit 298 Indicator, Throw-back 540 Indicator, Volt 568 Indifferent Electrode 210 Indifferent Point 421 Induced Current 163 Induced Magnetization, Coefficient of 354, 359 Inductance 298 Inductance Balance 293 Inductance Bridge 293 Induction, Anti-, Conductor 36 Induction, Back 55 Induction Balance, Hughes 291 Induction, Coefficient of Magnetic 349 Induction, Coefficient of Mutual 301 Induction, Coefficient of Self- 298 Induction Coil 133 Induction Coil, Inverted 136 Induction Coil, Telephone 137, 526 Induction, Cross 298 Induction Current 163 Induction, Electro-magnetic 218, 299 Induction, Electrostatic 302 Induction, Electrostatic, Coefficient of 234 Induction, Horizontal 302 Induction, Lateral 302 Induction, Lines of 330 Induction, Magnetic 302, 346 Induction, Magnetic, Apparent Coefficient of 346 Induction, Magnetic, Coefficient of 346 Induction, Magnetic Dynamic 347 Induction, Magnetic, Self- 352 Induction, Magnetic Static 347 Induction, Magnetic, Tube of 347 Induction, Mutual, Electro-magnetic 302 Induction, Mutual, Electrostatic 303 Induction, Open Circuit 303 Induction, Oscillatory 398 Induction Protector, Mutual 481 Induction, Self- 303 Induction Sheath 303 Induction. Unipolar 304 Induction, Unit of Self- 304 Induction, Vertical 304 Inductive Capacity, Magnetic 346, 349 Inductive Effect, Counter- 204 Inductive Resistance 466 Inductophone 304 Inductor 305 Inductor Dynamo 199 Inductor Generator 199 Inductor, Magneto- 363 Inductor, Pacinotti's 400 Inductorium 138 Inertia 305 Inertia, Electro-magnetic 305 Inertia, Magnetic 347 Infinity Plug 305, 420 Influence, Electric 305 Influence Machine 334 Influence Machine, Armature of 46 Influence Machine, Holtz 334 Influence, Magnetic 346 Installation 305 Instantaneous Capacity 102 Insulating Stool 305 Insulating Tape 305 Insulating Varnish 306 Insulation, Electric 305 Insulation, Magnetic 347 Insulation, Oil 396 Insulation Resistance 466 Insulator 306 Insulator Caps 306 Insulator, Fluid 306 Insulator, Line or Telegraph 306 Intensity 306 Intensity Armature 45 Intensity Current 163 Intensity, Electro-motive 228 Intensity, Magnetic 348 Intensity of a Magnetic Field 306 Intensity of Magnetization 360 Intensity, Poles of 426 Inter-air Space 489 Intercrossing 307 Interference, Armature 45 Interferric Space 489 Interior Pole Dynamo 191 Interlocking- Electro-magnets. 229 Intermediate Metals, Law of 323 Intermittent, 307 Internal Characteristic 114 Internal Resistance 466 lnterpolar Conductor 307 Interpolar Region 307 Interpolation 307 Interrupter, Electro-magnetic, for Tuning Fork 307 Intrinsic Efficiency 205 Invariable Calibration 97 Inverse Induced Current 163 Inverse Squares, Law of 323 Inversion, Thermo-electric 533 Ions 307 Iron 308 Ironclad Dynamo 200 Ironclad Electro-magnet, 219 Ironclad Magnet 356 Iron Disc Ammeter, Eccentric 27 Iron, Electrolytic 308 Iron, Galvanized 265 Ironwork Fault of a Dynamo 308 Irreversible Heat 286 Isochasmen Curve 171 Isochronism 308 Isoclinic Lines 308 Isoclinic Map 308 Isodynamic Lines 308 Isodynamic Map 308 Isoelectric Points 422 Isogonal Lines 308 Isogonic Map 309 Isolated Distribution 309 Isolated Plant 309 Isolated Supply 309 Isotropic 309 Isthmus Method of Magnetization 360 I. W. G., 309

J 309 Jablochkoff Candle 160 Jack. Spring- 492 Jacketed Magnet 356 Jacobi's Law 309 Jacobi's Method of Magnetization 360 Jacobi's Unit of Current 163 Jacobi's Unit of Resistance 466 Jamin Candle 100 Jar, Leyden 325 Jar, Lightning 330 Jar, Luminous 332 Jars, Leyden, Charging and Discharging 108 Jar, Unit 554 Jewelry 309 Joulad 311 Joule 311 Joule Effect 311 Joule's Electro-magnet 337 Joule's Equivalent, 311 Joint, American Twist 309 Joint, Britannia 309 Joint, Butt 310 Joint Current 160 Joint, Lap 310 Joint, Marriage 310 Joint, Resistance 464 Joints in Belts 311 Joint, Sleeve 310 Joint, Splayed 311 Junction Box 311 Junction, Thermo-electric 533

K. 311 Kaolin 311 Kapp. Line of Force 312 Kathelectrotonus 312 Kathode 312 Kathodic Closure Contraction 312 Kathodic Duration Contraction 312 K. C. C. 312 K. D. C. 312 Kempe's Discharge Key 315 Keeper 312 Kerr Effect 235, 312 Kerr's Experiment 312 Key 313 Key Board 313 Key, Bridge 313 Key, Double Contact 314 Key, Double Tapper 314 Key, Charge and Discharge 313 Key, Increment 314 Key, Kempe's Discharge 315 Key, Magneto-electric 315 Key, Make and Break 316 Key, Plug 316 Key, Reversing 316 Key, Sliding-contact 316 Key, Telegraph 316 Kicking Coil 132 Kilo 316 Kilodyne 316 Kilogram 317 Kilojoule 317 Kilometer 317 Kilowatt 317 Kine 317 Kinnersley's Thermometer 536 Kinetics, Electro- 211 Kinetic Energy 241 Kirchoff's Laws 317 Knife Break Switch 501 Knife Edge Suspension 317 Knife Edge Switch 501 Knife Switch 501 Knot 317 Kohlrausch's Law 317 Kookogey's Solution 318 Krizik's Cores 318

L 318 Lag, Angle of 33, 318 Lag, Electric 332 Lag, Magnetic 348 Lalande & Chaperon Battery 69 Lalande-Edison Battery 69 Lamellar Distribution of Magnetism 357 Laminated 318 Laminated Core 154 Laminated Core, Tangentially 155 Lamination 318 Lamination of Armature Conductors 319 Lamination of Magnet 361 Lamp, Arc 319 Lamp, Arc, Double Carbon 191 Lamp Carbons, Flashing of Incandescent 257 Lamp, Carcel 108 Lamp, Contact 320 Lamp, Differential Arc 320 Lamp Globe, Waterproof 572 Lamp, Holophote 321 Lamp-hour 321 Lamp, Incandescent 321 Lamp, Incandescent, Chamber of 113 Lamp, Incandescent, Three Filament 322 Lamp, Life of Incandescent 327 Lamp, Lighthouse 322 Lamp, Monophote 321 Lamp, Pilot 323 Lamp, Polyphote 323 Lamp, Semi-Incandescent 323 Lamp-socket 323 Lamps, Bank of 323 Lane's Electrometer 226 Langdon Davies' Rate Governor or Phonophone 450 Lenz's Law 325 Lap Joint 310 Lap Winding 570 Latent Electricity 323 Lateral Discharge 188 Lateral Induction 302 Latitude, Magnetic 348 Law, Jacobi's 309 Law, Kohlrausch's 317 Law, Lenz's 325 Law of Angular Currents 165 Law of Electrolysis 213 Law of Intermediate Metals 323 Law of Inverse Squares 323 Law of Magnetic Attraction and Repulsion. Coulomb's 338 Law of Successive Temperatures 324 Law, Magnus' 367 Law, Ohm's 396 Law, Pflüger's. 409 Law, Right Handed Screw 324 Law, Sine 486 Laws, Kirchoff's 317 Laws of Thermo-electricity, Becquerel's 78 Law, Tangent 502 Law, Voltametric 567 Lead 324 Lead, Angle of 33 Lead Chloride Battery 66 Lead of Brushes 90 Lead of Brushes, Negative 324 Lead, Peroxide of, Battery 69 Lead Sulphate Battery 66 Lead Tee 504 Leading Horns 324 Leading-in Wires 324 Leak 324 Leakage 324 Leakage Conductor 325 Leakage, Electro-magnetic 219 Leakage, Magnetic. 348 Leakage, Surface 498 Leclanché Agglomerate Battery 66 Leclanché Battery 66 Leg of Circuit 325 Legal Ohm 395 Legal Quadrant 444 Legal Volt 568 Length of Spark 490 Letter Boxes, Electric 325 Leyden Jar 325 Leyden Jar, Armature of 46 Leyden Jars, Battery of 68 Leyden Jars, Charging and Discharging 108 Leyden Jars, Sir William Thomson's 326 Lichtenberg's Figures 327 Life Curve 171 Life of Incandescent Lamp 327 Light, Electro-magnetic, Theory of 219 Light, Maxwell's Theory of 369 Lighthouse Lamp 322 Lightning 327 Lightning Arrester 328 Lightning Arrester, Counter-electro-motive Force 329 Lightning Arrester Plates 329 Lightning Arrester, Vacuum 329 Lightning, Ascending 330 Lightning, Globe or Globular 330 Lightning Jar 330 Lightning, Back Stroke or Shock of 55 Lime, Chloride of, Battery 61 Limit, Magnetic 348 Limit of Magnetization 361 Linear Current 164 Lineman's Detector 180 Line of Commutator, Neutral 300 Line of Contact 330 Line of Force, Kapp 312 Line of Magnet, Neutral 361 Line or Telegraph Insulator 306 Lines, Halleyan 308 Lines, Isoclinic 308 Lines, Isodynamic 308 Lines, Isogonal 308 Lines, Isogonic 308 Lines of Force 330 Lines of Force, Cutting of 175 Lines of Force, Electro-magnetic 219 Lines of Force, Electrostatic 234 Lines of Force, Magnetic 348 Lines of Induction 330 Lines of Slope 330 Lines or Points of Least Sparking 490 Lines, Trunk 550 Links, Fuse 330 Liquids, Electro-dynamic Rotation of 474 Liquids, Electro-magnetic Rotation of 475 Liquor, Spent 491 Listening Cam 330 Lithanode 331 Load 331 Load Curve 172 Load of Armature 46 Local Action 331 Local Battery 331 Local Circuit 331 Local Currents 163, 331 Localization 331 Locus 331 Lodestone 332 Logarithm 332 Logarithms, Hyperbolic 389 Logarithms, Napierian 389 Local Battery 66 Long Coil Magnet 361 Long Range Electro-magnet 220 Long Shunt and Series Winding 579 Long Shunt Winding 579 Loop 332 Loop Break 332 Loop, Circuit 125 Loop, Drip 192 Lost Amperes 30 Lost Volts 571 Low Vacuum 557 Luces 332 Luminous Jar 332 Luminous Pane 401 Luminous Tube 550 Lux 332

M 332 Machine, Cylinder Electric 333 Machine, Electric, Wimshurst 577 Machine, Frictional Electric 333 Machine, Holtz Influence 334 Machine, Hydro-electric 293 Machine, Influence 334 Machine, Nairne's Electrical 389 Machine, Plate Electrical 417 Machine, Rheostatic 472 Machine, Toeppler-Holtz 334 Machine, Wimshurst 335 Mack 335 Magic Circle 119 Magne-crystallic Action 335 Magnet 335 Magnet, Anomalous 335 Magnet, Artificial 335 Magnet, Axial 336 Magnet, Bar 336 Magnet, Bell Shaped 336 Magnet Coils, Sheath for 481 Magnet, Compensating 336 Magnet, Compound 336 Magnet, Controlling 185, 336 Magnet, Damping 336 Magnet, Deflection of 337 Magnet, Directing 185 Magnet, Electro- 215, 337 Magnet, Equator of 337 Magnet, Field 337 Magnet, Haarlem 337 Magnet, Heating 286 Magnet, Horseshoe 337 Magnet, Ironclad 356 Magnet, Joule's Electro- 337 Magnet-keeper 361 Magnet, Lamination of 361 Magnet, Long Coil 361 Magnet, Natural 361 Magnet, Neutral Line of 361 Magnet, Normal 361 Magnet Operation 365 Magnet, Permanent 365 Magnet Pole 365 Magnet, Portative Power of 366 Magnet, Projecting Power of a 435 Magnet, Relay 457 Magnet, Simple 366 Magnet, Solenoidal 366 Magnet, Sucking 366 Magnet, Unipolar 366 Magnet Coil 336 Magnet Core 336 Magnet Poles, Secondary 366 Magnet Pole, Unit 366 Magnetic Adherence 338 Magnetic and Electro-magnetic Equipotential Surface 244 Magnetic Attraction 338 Magnetic Attraction and Repulsion, Coulomb's Law of 338 Magnetic Axis 338 Magnetic Azimuth 338 Magnetic Battery 338 Magnetic Bridge 338 Magnetic Circuit 340 Magnetic Circuit, Curve of Saturation of 174 Magnetic Concentration of Ores 340 Magnetic Concentrator 340 Magnetic Continuity 340 Magnetic Conductance and Conductivity 340 Magnetic Control 341 Magnetic Couple 341 Magnetic Creeping 341 Magnetic Curves 341 Magnetic Cut Out 175 Magnetic Declination 342 Magnetic Density 342 Magnetic Dip 342, 346 Magnetic Discontinuity 342 Magnetic Double Circuit 340 Magnetic Eye, Electro- 248 Magnetic Elements 342 Magnetic Elongation 344 Magnetic Equator 344 Magnetic False Poles 350 Magnetic, Ferro- 252 Magnetic Field, Intensity of a 306 Magnetic Field of Force 344 Magnetic Field, Uniform 345 Magnetic Figures 345 Magnetic Filament 345 Magnetic Fluid, North 357 Magnetic Fluids 345 Magnetic Flux 345 Magnetic Force 346 Magnetic Friction 295, 346 Magnetic Friction Gear 276 Magnetic Fluid, South 356 Magnetic Foci 259 Magnetic Gear 346 Magnetic Hysteresis 294 Magnetic Inclination 346 Magnetic Induction 302 Magnetic Induction, Apparent Coefficient of 346 Magnetic Induction, Coefficient of 346-349 Magnetic Induction, Dynamic 347 Magnetic Induction, Static 347 Magnetic Induction, Tube of 347 Magnetic Inductive Capacity 349 Magnetic Inertia 347 Magnetic Influence 346 Magnetic Insulation 347 Magnetic Intensity 348 Magnetic Lag 348 Magnetic Latitude 348 Magnetic Leakage 348 'Magnetic Limit 348 Magnetic Lines of Force 348 Magnetic Mass 349 Magnetic Matter 349 Magnetic Memory 349 Magnetic Meridian 349 Magnetic Moment 349 Magnetic Needle 349 Magnetic Needle, Declination of the 178 Magnetic Needle, Dip of 185 Magnetic Needle, Oscillation of a 397 Magnetic Output 399 Magnetic Parallels 349 Magnetic Permeability 349 Magnetic Perturbations 350 Magnetic Poles 350 Magnetic Potential 350, 431 Magnetic Proof Piece 350 Magnetic Proof Plane 350 Magnetic Quantity 350 Magnetic Reluctance 351, 458 Magnetic Reluctivity 351 Magnetic Remanence 358 Magnetic Repulsion 338 Magnetic Resistance 458 Magnetic Retentivity 351 Magnetic Rotatory Polarization 351 Magnetic Saturation 251 Magnetic Screen 351 Magnetic Self-induction 352 Magnetic Separator 352 Magnetic Shell 352 Magnetic Shell, Strength of 352 Magnetic Shield 353 Magnetic Shunt 353 Magnetic Storms 353 Magnetic Strain 354 Magnetic Stress 354 Magnetic Susceptibility 254, 359 Magnetic Tick 354 Magnetic Top 542 Magnetic Twist 354 Magnetic Vane Ammeter 27 Magnetic Variations 354 Magnetism, Ampere's Theory of 354 Magnetism, Blue 355 Magnetism, Components of Earth's 356 Magnetism, Creeping of 356 Magnetism, Decay of 356 Magnetism, Discharge of 356 Magnetism, Electro 220 Magnetism, Ewing's Theory of 356 Magnetism, Free 356 Magnetism, Hughes' Theory of 357 Magnetism, Lamellar Distribution of 357 Magnetism of Gases 357 Magnetism, Red 357 Magnetism, Residual 358 Magnetism, Solenoidal Distribution of 358 Magnetism, Sub-permanent 358 Magnetism, Terrestrial 358 Magnetism, Weber's Theory of 358 Magnetization by the Earth 359 Magnetization by Double Touch 358 Magnetization by Separate Touch 359 Magnetization by Single Touch 359 Magnetization, Coefficient of Induced 359 Magnetization Curve 172 Magnetization, Cycle of 360 Magnetization, Elias' Method of 360 Magnetization, Hoffer's Method of 360 Magnetization, Intensity of 360 Magnetization, Isthmus Method of 360 Magnetization, Jacobi's Method 360 Magnetization, Limit of 361 Magnetization, Maximum 361 Magnetization, Specific 361 Magnetization, Surface 356 Magnetizing Coil 127 Magneto 361 Magneto Bell 80 Magneto Call Bell 361 Magneto-electric 361 Magneto-electric Brake 362 Magneto-electric Generator 362 Magneto-electric Generator, or Dynamo, Flashing in a 257 Magneto-electric Key 315 Magneto-electric Telegraph 512 Magnetograph 363 Magneto-inductor 363 Magnetometer 363 Magnetometer, Differential 365 Magnetometry 364 Magneto-motive Force 365 Magnetophone 367 Magnetoscope 365 Magnifying Spring Ammeter 28 Magnus' Law 367 Main Battery 66 Main Battery Circuit 125 Main Circuit 125 Main or Standard Feeder 251 Mains, Electric 367 Make 367 Make and Break Current 164, 367 Make and Break Key 316 Make-induced Current 163 Malapterurus 367 Map, Declination 309 Map, Inclination 297 Map, Isoclinic 308 Map, Isodynamic 308 Map, Isogonic 309 Marié Davy's Battery 67 Marine Galvanometer 269 Mariner's Compass 142 Marked End or Pole 368 Marriage Joint 310 Mass, Electric 368 Mass, Magnetic 349 Master Clock 127 Mathematical Element 237 Matteueci's Experiment 369 Matter, Electric 368 Matter, Fourth State of 261 Matter, Magnetic 349 Matter, Radiant 368 Matter, Ultra Gaseous 551 Matthiessen's Meter-gram Standard Resistance,. 466 Matthiessen's Unit of Resistance 466 Matting, Electric Floor 369 Maximum Magnetization 361 Maxwell's Theory of Light 369 Mayer's Floating Magnet 370 Maynooth's Battery 67 Measurement, Absolute 8 Measurements 370 Mechanical Equivalent of Heat 286 Mechanical Energy 241 Mechanical Equivalent, Electro- 244 Medical Battery 67 Medium, Polarization of the 424 Meg or Mega 370 Meidinger's Battery 68 Memoria Technica, Ampére's 30 Memory, Magnetic 349 Mercury 371 Mercury Bichromate, Battery 63 Mercury Circuit Breaker 121 Mercury Cups 371 Mercury, Sulphate of, Battery 67 Mercurial Air Pump 16 Meridian, Astronomical 372 Meridian, Geographic 372 Meridian, Magnetic. 349 Merit, Figure of 256 Merit, Formula of 256 Metal, Gilding 277 Metallic Arc 39 Metallic Circuit 125 Metallochromes 392 Metallurgy, Electro- 222 Metals, Law of Intermediate 323 Meter. Alternating Current 373 Meter, Ampere and Volt, Galvanometer . 274 Meter, Balance Ampere 391 Meter Bridge 373 Meter Bridge, Slide 486 Meter Candle 374 Meter, Chemical Electric 375 Meter, Current 375 Meter, Electro-magnetic 375 Meter, Energy 375 Meter Gram Standard Resistance, Matthiesen's 466 Meter-millimeter 375 Meter-millimeter Unit of Resistance 466 Meter, Neutral Wire Ampere. 391 Meter, Quantity 445 Meters. Ampere 39 Meter, Thermal-Electric 375 Meter, Time Electric 375 Meter, Watt 375 Method, Broadside 89 Method, Deflection 178 Method, End on 238 Method, Idiostatic 295 Method, Multiple Wire 388 Method, Null 393 Method of Magnetization, Elias' 360 Method of Magnetization, Isthmus 360 Method of Magnetization, Jacobi's 360 Methven Standard or Screen 376 Mho, 376 Mica 376 Mica, Moulded 376 Micro 376 Micrometer 376 Micrometer, Arc 39, 376 Micrometer, Spark 470 Micron 376 Microphone 376 Microphone Relay 377, 457 Microscope. Photo-electric 410 Microtasimeter 377 Mil 379 Mil, Circular 379 Mil-foot 379 Mil-foot Unit of Resistance 467 Milli 379 Milligram 379 Millimeter 379 Milli-oerstedt 380 Mil, Square 379 Minute, Ampere- 30 Mirror Galvanometer. 271 Mixed Gases 275