None
Liberated in Sulphuric Acid Voltameter, 82 Ion, Definition of, 88 Independence of Currents in Parallel Circiuts, 525 Induction, Electric, Definition of, 218 Inertia, Moment of. Determination of. Note, 79 Instruments for Measuring, Methods of Increasing Indications of, 43 Insulating Stand, Advantages oi Special Form of, 217 INS INDEX. JOU 625 [nsulatiDg Stand, Deseription of, 916 iDsnlator, Electric. Meaniog of, 14, 276 Internatioiial- Ampere, Definition of, 590 Ohm, Definition of, 178, 601 ^— Ohm in Terms of Legal Ohm and RA. Unit, 174 Volt, Definition of, 174, &90 Volt in Terma of Legal and B.A. Volts, 175 Interpolation, Definition of, 55 Invanable Sensibility, Galvanometers of, 127 Iron Filings for Magnetic Lines of Force Diagrams, Preparation of, 566 Filings, Mapping Out Lines of Force with, 71-75, 77 Magnetised by Current, 8, 5, 10 Belative Electric and Heat Conductivities of, 276 Resistance of, per Centimetre Cube and per Inch Cube, 250,271 — — Resistance of, per Foot Grain and per Metre Gramme, 261 — — Resistance, Percentage Varia- tion of, per 1°C., 266, 271 Wire. Disadvantages of, for Re- sistauces, 269 Jacobi's Proposed Standard of Re- sistance, 660 •* Ja Ja " Wire, Use of, Note, 812 Wir^ Resistance of, per Centi- metre Cube, 271 ; Note, 812 Wire, Resistance, Percentage Temperature Variatiou of, 271 ; Note, 812 Jenkin, Fleeming. and Clerk Max- well's Article on Elementary Relations between EiectriciU Measurements, Reference to, 574 Jones, Viriamu, * Determination of Length of Mereury Column Representing One Ohm by, « 586,609 Joule, Electrical Determination of Mechanical Equivalent of Heat bv, 676 Determination of Ohm by, 682 Definition of, 817, 601 Value of, in Foot Pounds and in Ergs, 817 Joules, Value of Board of Trade Unit in, 840 per Second, Value of Watt in, Joulemeter, Definition of, 884 Aron Type of Gaining Clock Form, 888 Ayrton and Perry's Original Gaining Clock Form, 834-888 Clock, Force Between Coils of. Small Compared with Force of Gravity, 886 Clock, Gain or Loss of, in Fixed Time Proportional to Energy Given to Cirouit, 886 dock. Limit to Proportionality between Gain of, and Energy Supplied, 888 Clock, Method of Joining Up and Using, 888 Clock, Permanent Magnet Pen- dulum Form, 888 Clock, Type Used when Energy Supplied at Constant Rate, 888 Clock, Varying Rate of Vibra- tion of Pendulum, 886 Elihu Thomson. (See Joule- meter, Thomson.) Motor, Ayrton and Perry's, Prin- ciple of, 841, 847 Motor, Armature of, 842 Motor, Commutator Used in, 842 Motor, Continuous Motion in. How Obtained, 842 Motor, Field of, 848 Motor, Method of Keeping Torque Constant between Field and Ai-mature in, 842 Motor, Type Used when En- ergy Supplied at Constant Pressure, 348 Thomson, Motor Form, 841-840 Thomson, Armature o^ 843 Thomson, Armature Rotation Proportional to Energy Sup- plied, 347 Thomson, Directions of Currents in Armature of, 844 Thomson, Driving Torque Pro. portional to Product of Strengths of Fields, 846 Thomson, Field Coils of, 845 Thomson, Fields Produced Armature and Field Coils 846 Thomson, Fields Proportional to Currents Producing them, 846 Tliomson, How to Overcome Friction in, 848 bv of. 626 JOU PBACTICAL KLECl'RICITY. LIN Joulemeter, Thomson, Retarding Torqne in, How Produced, 346 Thomson.Retarding and Driving Torques, Conditions Govern- ing JBquality between, 847 Joulemeters, Motor and Clock Forms of, Compared, 848 K Eahle's Modification of Bayleigh's H Fonn of Clark's Cell, 472 Kathode, Definition of, 24, 33 for Silver Voltameter, Descrip- tion of, 23, 26 Weights of Metals Deposited on, 27 Kelvin's Addition to Weber's Abso- lute System of Units, 571 Deflectional Wattmeter, 832 Method of Calculating E.M.F. of Cell fh)m Chemical Action, 477-479, 576 Moving Coil Galvanometer, Principle of, 130 Key for Making Two Sets of Connec- tions, 236 Bfethod of Cleaning Contact Points of, 287 Sliding, Use of Platinum Irid- ium Wire with, 510 Used with Wheatstone's Bridge, 250 Used with Shunt to Wheat- stone's Bridge, 252 Kilowatt, Value of, in Horse-Power, 327 Kimball and Rowland, Ohm Deter- mined by, 583 Rowland, and Duncan, Ohm Determined by, 583 Kirchhofl's Absolute Measurement of Resistance, 571 Kohlrausch, Ohm Determined by, 577, 582 Ijalande-ChAperon Cell, 462 Lamps, Glow. (See Glow Lamps.) Latimer Clark, Cell Devised by. {See Cell, Clark's.) Clark Proposes Names Oh mad and Volt, 573, 576 Lead Foil for Electroscope Leaves, When used, 106 Lead Foil, Relative Electric and Heat Conductivities of^ 275 Resistance of, per Centimetre Cube and i«r Inch Cube, 250 Resistance of, per Foot Grain and per Metre Gramme, 261 Resistance, Percentage Varia- tion of, for IT., 266 Leaves of Electroscope, 193-106 Leclanch^ Cell. (See Cell, Leclanch^) Legal Ohm, Definition of, 583 Ohm of 1884, Error in, 584 ; Note, 600 Ohm, Value of, in Terms of B.A. Unit and International Ohm, 174 Volt, Definition of, 683 Volt, Value of, in Terms of B. A. Volt and International Volt, 175 Legislation of Electrical Standards, 692 Lenz, Ohm Determined b^, 582 Proposed Unit of Resistance, 568, 569 Lighting, Electric, Accumulators Used in, 527 ^ Electric, Comparative Cost of Using Dynamo and Cells for, 482-491 Electric, Conditions for Com- mercial Use of Galvanic Cells for, 491 Electric, of House, 300 Electric, Legal Maximum Varia- tion of Pressure between House Mains, 358, 490 Electric, Method of Making Cur- rent in Each Lamp Inde- Smdent of Current in all ther8,302 Electric, P.D. between House Mains, 300 Electric, Resistance of House Wires Compared with Re- sistance of Lamp Filaments, 802 Lines of Force Diagi'ams, Preparation of Filings for, 566 of Force Diagrams, Preparation of Waxed Paper for, 666 of Force Mamied out by Using Compass Needle, 76 of Force Mapped out by Using Iron Filings, 71-75, 77 of Force, Methods of Mapping Out Compared, 77 of Force, Precautions in Mapping Out, 77 of Force with Bar Magnets, 72, 73 LIN INDEX. MAI 627 Lines of Force with Circular Coil Carrying Current, 71 of Force with Horse-shoe Mag- net8» 74, 75 Liquid Decomposed by Electric Current, 4, 10. {See also Cell, Chemical Action in.) Jjoad Diagram, Example of, S27 Local Action, Definition of, 429 Action, How Caused in Cell, 429 Action, Method of Preventing in Cell, 429 Action, None in Edison-Lalande Cell, ^64, 465 — Currents, Meaning of, 429 Lorenz, Ohm Determined by, 577, 582, 583 Loss of Head, Definition of, 153 of Head and Rate of Flow of Water, Curve Connecting, 168 Lower Potential, Definition of, 162 Low Besistanee Ammeter, Use of, as Voltmeter, 181 M Magnet and Conductor with Cm rent Passing, Force Exerted be- tween, 8, 129 ——Deflection of, by Electric Cur- rent, 8, 5, 34, 69 Forces Exerted on Compass Needle by Different Parts of, 67 Forces Exert-ed on Soft Iron by Different Parts of, 67 Motions of Rotation and Trans- lation Produced by, 138 North- seeking End of, Defini- tion of. Note, 34 Pendulum, Permanent, of Clock Joulemeter, 338 Permanent, Measuring Distribu- tion of Magnetism in, 63 Magnets, Force Exerted between, 63 Lines of Force due to, 72 Stationary, in Ammeters, Re- sults of Weakening, 135, 150, 151 Magnetic Axis, Definition of, 67 Control, How Produced in Moving Coil Ammeter, 150 — — Control, Moving Coil Ammeter with, 150 Experiments, Precautions Neces- sary when Making, 66 Field at Centre of Coil, Descrip- tion of, 80 Magnetic Field of Earth, Action of, 67, 77 Field of Earth, Arrangement for Neutralising, 78 Field of Earth, Disturbing Action of, on Another Mag- netic Field, 77 Field, Mapping Out Lines of Force in, 71-77, 565 Field, Relative Strengths of Different Parts of, 79 Field, Strength of, Definition of, 79 Field, Strength of, Measuring, 79 Field, Uniform, Definition of, 70 Field, Uniform, Method of Neu- tralising, 78 Field of Wesfem Ammeters and Voltmeters, 147 Fields of Thomson Joulemeter, and Driving Torque, 846 Fields of Tliomson Joulemeter Proportional to Currents Producing them, 346 Fields Produced by Armature and Field of Thomson Joule- meter, 345 Lines of Force Diagrams, Pre- paration of Filings and Waxed Paper for, 565 Lines of Force, Mapping Out, 71-77, 665 Needle, Why Tends to Point NorUi and South, 67 Polarity, and Direction of Cur- rent, Connection between, 35, 86, 69 Poles, Definition of. MBA Mains, House, P.D. l)etween, 801, 626 House, Resistance of, Compared with Resistance of Lamps, 802 House and Street, Impossibility of Keeping Flessure Con* stant at Every Junction of, 626 Method of Keeping Pressure between. Constant at Certain Points. 626 Manganese Alloys, Composition of, 268 -— - Dioxide Consumed in Leclanch6 Cell per Board of Trade Unit Produced, Wright and Cost of, 487 Dioxide Consumed in Leclanch^ Cell per Hour per 1,000 Am- peres, 484 Manganin, Composition of, 260 Resistance of, per Centimetre Cube, and per Inch Cube, 260, 200, 271 Resistance of, per Foot Grain and per Metre Gramme, 261 Resistance. Percentage Vai-iation of, with Temperature, 269, 271 ^— Specific Resistance of. Compared with that of Copper, 260 Used for Resistance Coils, 269, 280,619 Mapping out Lines of Force, 71-77, 666 Mascart Criticises Methods Used for Determining Ohm, 686 De Nerville and Benoit, Ohm Determined by, 682 Mather and Ayrton. (See Ayrton and Mather.) and Walmsley's Proportional Galvanometer, 126 Matthiessen, Law Connecting Varia- tion of Resistance of Metals with Temperature, 264 — Papers on Temperature Varia- tion of Resistonce of Metals and Alloys by. Reference to, 674 Maximum Current for Cell, Safety Limitation of, 559 Current Through Fixed External Resistance, Arranging Given Number of Cells to Produce, 646 Maxwell. Clerk, and Fleeming Jen- kin's Article on Elementary Relations between Electrical Measurements, Reference to, 674 Maxwell's Moving Coil Galvanometer, Principle of, 130 Measure of Current Strength, Choice of, 9-28 Measurements, Electrical, Com- mittees to Consider Units for, 672, 678, 679, 681, 584, 587, 588, 690, 692 Electrical, History of Units for, 668-600. (See also Ampere, Ohm, and Volt.) Measuring Back E.M.F. in Circuit 871 Current, Board of Trade De- scription of Method of, 25, 695 — — Current, Principle of Board of Trade Standards for, 688 Current with Ammeter, 127 {See also Ammeter.) Current with Calorimeter, 12 Current with Clark's Cell and Known Resistance, 619 Current with Electromagnet, 10 Current with Galvanometer, 43. {See alao Galvanometer.) Current with Galvanoscope, 10, 22 Current with Copper Voltameter, 10,26 Current with Silver Voltameter, 2S-29, 595 Current with Sulphuric Acid Voltameter, 10. 88, 89 Current with Voitaraeters and Galvanometers, Relative Ad- vantages of, 42 Current with Voltmeter and Fixed Resistance, 189 Currents Passing Through Two Conductors in Parallel, 238 Distribution of Magnetism in Permanent Magnet, 63 Distribution of Gas Pi'essiire, 168 Distribution of Water Pressure, 154 Electric Density, 224, 226 Electric Energy, 813-324, 834- 348. {See also Joulemeter.) Electricity Produced by Rubbing Two Bodies Together, 214 E.M.F. of Cell and of Battery, 362, 865, 477, 602-^10 E.M.F. of Current-Generator, when Variable, 869 E.M.F., Back, in Circuit, 871 Heat Equivalent of Electric Energy, 319 Instruments^ Methods of In- ereasing indications of, 48 MEA INDEX. MOT 629 Measuripg Quantities of Electricity, Relatively, 212 — — P.D. with Ammeter and Besist- ance. 185 P.D. wiUi Clark's Cell, 510, 516 P.D. with Current Voltmeter, 1T9 P.D. Electrostatically, 162, 191 P.D. (See alto Comparing P.Ds., 176.) P.D., Principle of Board of Trade Standards for, 588 Power, 825, 828. (See aUo Watt- meter.) Resistance with Ammeter and Voltmeter, 185, 232 Resistance with Ohmmeter, 233 Resistance. (See alw Comparing Resistances.) Resistance of Cell, Choice of Method for, 498 Resistance of Cell When Not Very Small, 498 Resistance of Cell, When Veiy Small, 366, 402 Strengths of Different Parts of Mimetic Field, 70 Variation of Resistance with Temperature, 262 Mechanical Energy, Conversion of Energy of Current into, 314 Meidinger GeU, 431 Mercnrous Sulphate for Clark's Cell, Preparation of, 468, 470, 507 Sulphate and Zinc Sulphate Paste for Clark's Cell, Pre- paration of, 468, 472, 508 Mercury, Effect of Adding Zinc, 430 for Clark's Cell, Preparation of, 467,597 and Copper, Relative Resist- ances of, 269 Ohm, Mass and Length of Column, 173, 589, 503 Ohm, Section and Length of Column, 580, 586,^87, 600 Resistance of, per Centimetre Cube and per Inch Cube, 260 Resistance of, per Foot Grain and per Metre Gramme, 261 Resistance, Percentage Varia- tion of, per 1*C., 266 Resistance of, at Any Tempera- ture, Formula Giving, 260 Siemens Unit, Section and Lenffth of Column, 570 Switch-board for Batteries, 170, 539 Switch-board, Method of Avoid- ing Possibility of Short- Circuiting Cell when Using, 540 Mercury Switch-board, Positions of Bridge Pieces of. Giving Dif- ferent Arrangements of Cells, 541 — — Trouglis Used as Adjustable Re- sistance for Large Currents, 270 Metallic Case, Advantage of En- closing Electrical Apparatus in, 197, 200 Metals, Law Connecting Variation nf Resistance of, with Temper- ature, 264 Resistances of, per Centimetre Cube and per Inch Cube, 257, 250, 271 Resistances of, per Foot Grain and per Metre Gramme, 261 Resistances of. Percentage Variation per I'C, 266 Resistances of. Relatively to Aluminium for Same Length and Weight, 261 Resistances of. Relatively to Silver for Same Length and Section, 259 Temperature Coefficients of Resistances of, 264-267 Meter, Aron Supply, 888 Aron Supply, Differential Gearing of, 340 Energy. OHM Motor, Method of Keeping Torque Constant between Field and Armature in, 842 Moving Coil Ammeter. {See Ammeter, Moving Coil. ) Coil Voltmeter, 183 Mnii'head's Telegraph Battery, 434 Multiplying Power of Shunt, Delini- tion of, 290 N Nalder Gravity Control Ammeter, 141 Needle of Compass. (See Compass Needle.) of Electrical Measuring Instru- ment, Definition of, Note^ 164 of Galvanometer. (See Galvano- meter Needle.) Magnetic, Why Tends to Point North and South, 67 Needles Used in Various Forms of Ammeters, 184, 140, 141, 142 Negative Charge, Whalj. is Meant by, 160, 218 Electrification, What is Meant by, 161 Plate of Cells. (See Plate, Nega- tive, of Cells.) Potential, Definition of, 162 Ncrville, De, Mascart, and Benoit, Ohm Determined by, 582 Neutralising Uniform Magnetic Field, Arrangement for, 78 Nickel, Resistance of, per Centimetre Cube and per Inch Cube, 259 Resistance of, per Foot Gmiu and per Metre Gramme, 261 Temperature Coefficient of Re- sistance of, 266 Nitric Add Consumed in Grove's Cell per Board of Trade Unit Pro- duced, Weight and Cost of, 486 — - Acid Consumed in Grove's Cell per Hour per 1,000 Amperes, 440, 441, 484 Acid, Heat Absorbed in Decom- p<»ition of, 481 Peroxide Formed per Hour per Ampere in Grove's Cell, 440, 441 Peroxide, Heat of Formation of, 481 Non-inductive Resistance Coil for Large Currents, Ayrton and Mather's, 282 North-Seeking End of Magnet, Defini- tion of, Note, 84 Obach Dr}' Cell, 460 Ohm, Board of Trade, Internationa], and Legal, l>efinitions of, 173, 578, 583, 587, 589, 691, 593 Legal, and International, and B.A. Unit, Values of, in Terms of Each Other, 174 B.A. Unit Less than, 576 Board of Trade Standard, 594, 595 Determined by British Associa- tion Committee, 581 Determined by Dorn, 682 Determined by Fletcher, 683 Determined by Hinstedt, 583, 585 Determined by Glazebrook, 582 Determined by Jones, 586, 600 Determined by Joule, 581 Determined by Eohlrausch, 577, 582 Determined by Lenz, 582 Determined by Lorenz, 577, 582, 588, 685 Determined by Mascart, De Nerville, and Benoit, 682 Determined by Rayleigh, 677, 581, 685 Determined by Rayleigh and Schuster, 581, 585 Determined by Rayleigh and Mrs. PHO 631 Ordinates, Definition of, 57 Oatflide Circuit (See Circuit, Ex- ternal.) Oxide of Copper. (See Copper Oxide. ) Oxygen Deposited on Copper Plate of Cell, Effect of, 402 and Hydrogen, Proportions of, Evolved in Sulphuric Acid Voltameter, 82 Liberated per Second per Ampere in Sulphuric Acid Volta- meter, 83 Parallax, Definition of, 60 How Avoided in Measuring- Instruments, 50, 831 Parallel, Apparatus in, Definition of, 20 and Parallel-Series, Cells Joined in, 586 and Parallel-Series, Joining Cells in, by Means of Mei-cury Switchboard, 541 Circuits, Independence of Cur- rents in, 525 — Conductors, Ratio of Currents in, to Current in Main, 295 —— Resistance, 291 P. D., Absolute Electromagnetic Unit of, Deflnition of, 479, 575 between Conductors Enclosing, One Another. 218 between Conductors, How Shown, 161 — — between House Mains, 801, 526 between Terminals of Battery, E.M.F., Resistance and Cur- rent, 864, 380 between Terminals of Batteiy when Maximum Power Given to External Circuit, 389, 548 between Terminals of Edison- Lalande Battery, Variation of, with Current Passing, 464 between Terminals of Cell, Cnn- stant with Low lutemal Re- sistance, 522 between Terminals of Clark's Cell, and Unit of Pressure, 589, 594 between Terminals of Hellesen Cell, Fall of, with Current Passing, 459 between Terminals of Obach Cell, Fall of, with Current Passing, 462 '-'- between Terminals of Circuit and Current, Power Given to Cir- cuit in Terms of, 326, 370 P.D. between Two Points of Uniform Conductor CouveyingCniTent Proportional to Disiance, 156 between Two Points of Con- ductor, Method of Maintain- ing Constant, 158, 510 Coinpared with Difference of Fluid Pressure, 154 Compared with Differeilce of Gas Pressure 158 Constant, 287, 522 and Current, Given, Minimum Number of Cells to Produce, 549 Definition of, 164, 163 Measuring with Ammeter and Resistance, 185 Measuring with Clark's Cell, 510, 516 Measuring with Current Volt- meter, 179 MeasnringElectrostatically, 162, 191 Power, and Current, Relation between, 327 Ratio of, to Current, Constant for Given Conductor, 170 Ratio of, to Current, for Given Conductor Experimentally Determined, 171 Ratio of, to Current, and Ratio of Difference of Pressure to Stream of Fluid, 167, 169 — ^ to Send Current round Eutiro Cireuit Constant for Given Battery, 861 Where Set up in Cell, 374 Units, Definitions of, 174, 176. 479, 575, 578, 583, 588, 589, 093 Units in Terms of Each Other, 175, 479 P.Ds., Comparing by Current Method, 176 Pendulum of Clock Jonlemeter, Vary, ing Rate of Vibration of, 336 Coil of Clock Joulemeter, 834 Permanent Magnet, of Clock Joulemeter, 838 Rate of Vibration of, 836 Permanent Magnet Ammeter. (See Ammeter, Permanent Mag. net.) Magnet, Distribution of Mag. netism in, 68 Perry and Ayrton. (See Ayrton and Perry.) Phosphor Bronze, Resistance of, per Centimetre Cube and per Inch Cube, 259, 271 632 PHO PRACTICAL ELECTRICITY. POR Phosphor Bronze, Resistance of, per Foot Grain, and per Metre Gramme, 262 Bronze, Resistance, Percentage Variation of, per I'C, 271 Pivot and Fibre Suspensions of Gal- vanometer Needle, 110 Plants, Invention of Accumolatoi's bv, 627 Plate, Carbon, of Cells, 448, 445, 450, 452, 458, 460, 461 Copper, of Cells, 419, 421, 431, 438,435 Copper, of Simple Voltaic Ele- ment, Liberation of Hydro- gen at^ 419 Copper, of Simple Voltaic Ele- ment, Experiment to Show Back E.M.F. Set Up at, 421 Copper, of Simple Voltaic Ele- ment. Polarisation at, 420,422 Copper Oxide, of Cell, 462, 468 Negative., of Cells, 419, 428, 431, 483, 435, 488, 448, 445, 450, 452, 458, 455, 460, 461, 462 Phitinum, of Cells,| 428, 438, 482 Positive, of Cell, Definition of, 876. (See cdao Plate, Zinc.) Zinc, of Cells, 419, 423, 431, 438, 485, 438, 445, 460, 454, 455, 458, 459, 460, 461, 462, 463 Zinc, Effect of Amalgamating, onE.M.F. POW 633 PoroQS Pot, Potassium Bichromate Cell with, 446 Portable Galvanometer, 127 Forms of Wheatstone's Bridge, 285 Positive Electrification, What is Meant by, 161 Plate of Cell, Definition of, 376 Plate of Cell. (See Plate, Zinc, of Cell.) Potential, Definition of, 162 Terminal of Cell, Definition of, 876 Post Office Wheatstone's Bridge, 285 Potassium Bichromate Cell, 445. (Set also Cell, Potassium Bichro- mate.) Bichromate Consumed in Cell Ser Board of Trade Unit Pro* uced. Weight and Cost of, 487 —-« Bichromate Consumed iii Cell per Hour per 1,000 Amperes, 484 Potential in Cell, Method of Varia- tion of. Uncertain, 874 of Conductor Proportional to Quantity of Electricity on Conductor, 2U of Conductor, What is M6ant by 200 Difference. (See P.D.) Distribution of, in Cell and Battery, Diagram Showing, 874 Distribution of, in Circuit, Dia- gram Showing, 876 Distribution of, in Circuit with Opposing E.M.F., Diagram Showing, 878 Distribution of, and of Fluid Pressure, 166, 167, 173 of Earth, Arbitrary Value Given to, 160 Electric, Compared with Fluid Pressure, 154, 156, 167, 173 Electric, Compared with Gas Pressure, 204, 207, 209, 231 Inside Closed Conductor, 197 Level, What is Meant by, 160 Measiu-ing, 160, 200. RES Power, Maxlmnm, firom Given Current Generator, Circuit that Re* ceives, 885 — Maximum, Arrangement of Bat- tery to Give, 845 — Maximum, Arrangement of Part of External Circuit to Re- ceive, 893 — — Maximum, Generator Can De- liver, 880 Meaaoring, 325, 828 P.D., and Current, Relation between, 82T, 870 — — Received, Variation of, firom Maximum and Change in Current, 898 •^— Received, Variation of, fh)m Maximum and Change in Re- sistanee, 899 — — Units of, in Terms of Bach Other, 827 Variable, Meaning of, 826 Pressure, Electric. (See P.D.) of fluid Compared witli Elec- tric Potential, 154, 155, 167, 178 of Gas Compared with Electric Potential, 204, 207, 209, 231 of Gas, Variation of, with Mass, 207,209 of Gas, Variation of, with Tem- perature, 204, 209 of Gas, Variation of, with Volume, 204,209 between Mains, Maximum Legal Variation of, 358. 490 between Mains, Method of Keep- ing Constant at Certam Points, 526 — — at Every Junction of House and Street Mains, Impossi- bility of Keeping Constant, 526 — — Principle of Instruments Adopted as Board of Trade Standa^rds for Measurement of, 588 Electrical Standards of, 595 Unit of. (See Unit of P.D.) Variation of Light of Glow Lamp with, 490 Price of Board of Trade Unit, 849 Primary Current, Direction of, in Experimental Voltaic Ele- ment,428 Proof Plane, Description of, 224 Plane, Method of Measuring Charge on, 224 Properties of Electric Current, 8, 5 of Electric Current, Practical Uses of, 9 Plroperty by which Current Strength is Best Measured, 10-22 Proportional Coil, 284, 287. {See also Coil, Proportional.) Galvanometer. (See Galvano- meter, Proportional.) Protractor, Use of, 59 Quantities of Electricity, Comparing, 211-217 Quantity of Electricity Produeed by Rubbing Two Bodies To- gether, 214 of Electricity, Unit of, 679 of Electricity, What is Meant by, 208 Potential, and Density, Ex- amples Showing Difference between, 226 Rayleigh, Ohm Determined by, 577, 581 and Mrs. Sidgwick, Ohm Deter- mined by, 582 and Scliuster, Ohm Determined by, 681 Rayleigh's H Form of Clark's Cell, 466 Recording, Graphically, Results of Experiments, 50 Wattmeter. (See Joulenieter, Thomson.) Reduced LengUi of Conductor, What was Meant by, 568 Relative Calibration of Galvanometer, Meaning of, 45 —-Conductivities of Metals, per Cubic Unit, 275 Resistances of Metals and Alloys, 259, 261 Resinous Electrification, Definition of, 161 Resistance, 14, 172 Absolute Electromagnetic Unit of, 573, 591. (See aleo Unit of Resistance.) of Accumulator, 527 of Alloys, 259. 261. (See aXto Re- sistance of Metals.) Alloys with Lowest Tempera- ture Variation of, 267-269 Apparent) of Arc, Measuring, 238 RES INDEX/ BBS 635 Resistance, Apparent, of Arc, What is Heftnt by, 288 B.A. Unit of, 678. (Ste also Unit of Resistance, B. A. ) of Battery with Cells Joined in Parallel, and in Parallel- Series, 688 of Battery of Given Number of Cells Sending Maxininm Current, 646 of Battery, P.D. between Ter- minals, E.11.F., and Current, 8H880 Box, constmction and Use of, 278,379 Box, Values of Coils for, 288 of Cell, Conditions Governing, 484 of Cell, Ohoiee of Method for Measuring, 496 of Cell, Measuring, Wlien Not Very Small, 498 of Cell, Measuring When Very Small, 866, 492 of CelL P.D. between Terminals, E.M.F., and Current, 864, 880-888 of Cell, and P.P. Maintained, 287, 622 and Clark's Cell Used as Cur- rent Standard, 619 used with Clark's Cell to Restore its E.M.F. to Normal Value, 477 of Daniell's Cell, Increase of, with Constancy and Porta- bility, 481 of Daniell's Cell, Variation of, with Temperature, 486 of Valious Forms of Daniell's Cells, 486 of Edison-Lalande Cell, 464 of Grove's Cell. 440 of Grove's Cell Increases with Use of 441 of Hellesen Dry Cell, 469 of Obach Dry Cell, 462 of Storage Cells, 627 of Circuit, Change in, with Use of Shunts, 807 of Circuit, and Heat Energy Produced in, 818, 870 of Circuit, Percentage Loss of Power Due to, 410 of External Circuit, and Power Received by Circuit, Con- nection between, 892, 899 of External Circuit, and Cost of Production of Electric Energy, 483 — — Coil,. Ayrton and Mather's Non< Induclive, for Large Currents, 232 Resistance Coil, Standard, 276 Coils, Description of, 46 Coils, Earliest Form of, 669 Coils, Kind and Gauge of Wire Used in, 281, 282, 619 Coils, Method of Avoiding Magnetic Effect of, 281 Coils, Method of Dissipating Meat Produced in, 281 Coils Specific Resistance and Percentage Temperature Vari- ation of Materials Used in, 271 Coils^ Variation and Measure- ment of Temperature of, 280, 281 Coils, When Used, 278 Coils, Winding, 280 Combined, 291 Combined, in Terms of Resist- ances of Branch Circuits, 292,298 of Conductor, Conditions Affect- ing^ 268-271. (See cUeo Resistances, Com- paring.) "^ Measuring, with Ohmmeter, 283 Mercury Troughs Used as, 270 Metal having Least, for Given Length and Weight, 261 Metals having Least and Greatest, for Given Length and Section, 260 of Metals and Alloys, Law Connecting Variation of, with Temperature, 264, 266 of Metals and Alloys per Centi- metre Cube, and per Inch Cube, 267, 269, 271 of Metals and Alloys per Foot Grain and per Metre Gramme, 260 PBACTICil, RLECTRICITT. i Alloyi, Teinpon- i Alloyi orBMlBti — IMiallel, i — of HbUduiii, Teinpentnie Tu-in — Bpeciflc, H»w EipreHed. ^X MBtJTiBls, Kelntinn letwoon, nr — Teating Tcmporatnre Vsrtatinn — Unit of. Olini, Dennltlon of, lis, 676, 66S, fiS?, &ei. BBS. (S» idto Ohm.) — UnlU of. (Sm Unit of ttAalBt — »noea.) — Vnriition of, nitb Grou-aeotioD, 3oiiip«ring, by Dff- iviaing Wire [nto nlle'l witli Battery, Safety LiiniUUon of Maxlronm Cur Sal AiDDionlBC ConsuuiHl In Le CisDCbi Cell per Board n -snomeUr Giving 11. ._ live Strengtha ot Ciimnta, Constractiaa of, 69 Uve gtreogtba of Cuireiit, Subdividing Angular Spnces of Gravity Couttol Alnnielers, 1S9, 144 of Kagnlfrlna Spring Ani. incfer, Con3iUoiu governing Equality of Dlvlilous of, 13C, orObmuielor, MO ■ — - of Periiiauent Magnet Ammeler, for Tangent GiilvBnoiiKtcr, Con- or Valtnietec, Direct Reading Electroat«tle, Conatractior roundibgCbarged Body, Con- ditions Ooveniing, !fS — CondustHir whm Comparing OntSdfl Space f,-on. InaMe Elec trostatlc Action, 222 2S8,aSo Seeraidarv Current, Direction of. in Foiixa, Method of ment, *W l«nniiied'by,5T,5a2 Self-lndusliou, Uultof,09l Sensibility in Animetera. Adjnat- menta for las. ISi, Mi, 160 Dnncsan, Obm Da- iV.M3 aI43ohl-leafElei;tio«»p<ia,lM 8BN INDEX. SIM 637 Sensibility of TaDsent Galvanometer, Law and Variation of, 91, 98, 100,102 in Voltmeter, At^astment for {ExamT^ 80, 31), 187, 188 Series, Apparatus in, Definition of, 20 and Parallel-Series, Cells Joined in, 536, 537 and Parallel-Series, Joining Cells in, by Means of Mercury Switch-board, 541 Sliort-Circniting Cell, when Using Mercury Switch-board, How to Avoid Possibility of, 540 Ammeter, Resnlt of, 181, 182 Voltmeter, Result of, 181, 182 Shunt, Description of, 110 ^and Qalvanometer, Ratio of Currents in, 290 and Galvanometer, Ratio of Cur- rent in each to Whole Current, 290 Increase of Main Current Pro- duced by Applying, 298 Multiplying Power of, Definition of, 290 Use of, and Calibration of Gal- vanometer, 110 Used with Dliferential Galvano- meter,. 241, 811 Used with Galvanometer, 110 Used with Wheatstone's Bridge, 252 Variation of Effect of, on Cur- rent, with Change of Ex- ternal Resistance, 209 Shunts, Parallel Arrangement of, 297 Series Arrangement of, 207 Universal,' Principle and Use of, 803 Shunt Box. Ayrton and Mather's Universal, Construction of, 804 Box, Universal, Advantages of, 306 Box, Universal, Change In Re- sistance of Circuit Produced by Using, 307 - — Box, Universal, Employed with Any Galvanometer, 308 Box, universal, Facility in Ad- justing Coils, 307 B<:>x, Universal, Independent of Variations of Temperature While Using, 306 Box, Universal, Selection of Re- sistance for, 309 Box, High Insulation, Construc- tion of, 297 Box, Usual Form of, Arrange- ment of Coils in, 295 Shunt Box, Usual Form of, Necessity for Constant Temperature whUe Using, 806 - — Box, Usual Form of. Employ- ment of, 296 Box, Usiuil Form of. In, 422 638 SIM PBACTICAX. BLSOTRICITY SWI K r Simple Voltaic Element, Polarisation in, Cause and Effect of, 420 Sine of Angle, Definition of, 111 Galvanometer, 118, 119. (See cdso Galvanometer, Galibra- ting Qn Sine Principle.) - ! Law, 112 Law Experimentally Tested, 118-118 Law, Methods of Keeping Angle Between Deflecting Force and Deflected Body Constant, 118 Principle Employed in Galvano- meters, 118 Single Circnit, Definition of, 877 Circuit Electromotor, Definition of, Note, 871 Fluid CeUs, 418, 446, 450, 462 Slider witli Wire Bridge, 240, 260 Smee's Cell, 428, 482 Sodium Bichromate, Chromic Acid for Cell Formed from, 448 Solder to Use with Phosphor Bronae Suspension, 149 Spark, Electric, Shows P.D. between Conductors, 161 Specific Gravities of Mixtures of Sul* phuric Acid and Water, 80 Heat, Definition of, Note, 262 ^— Besistance of Copper, Variation of, with llensity, 268, Nate, 812 Besistance of a Material, How Expressed, 257 Resistances of Materials Used in Besistance Coils, 271 ^-^ Resistances of Metals and Alloys per Centimetre Cube and per Inch Cube, 257, 269 Resistances of Metals and Alloys per Foot Grain and per Metre Gramme, 260, 261 Spring-B^anoe, Methods of Increas- ing Indications of, 48 Magnifying, Description of, 64 Magnifying, Law of, 65 Squared Paper. Use of, 50, 63 Stand, Insulating, Description of, 216 Standard of Current, Board of Trade, 687, 694, 605 of Current, Use of Clark's Cell and Known Besistance as, .619 of Pressure, Board of Trade, 688,696 of Resistance, Board of Trade, 687, 694, 696 Resistance Coil, 276 -— Resistance Used in Measuring Current, 620 ; Standards, Board of THule, Irimits to Accuracy of, 696 Board of Trade, for Measuring Current and Pressure, 588 Board of Trade, Where Kept, 695 >^— Electrical, Legislation of, 690 Storage Cell. (See Accumulator.) Strength of Current, Definition of, 23 of Current, Measuring. (See Measuring Current.) of Current, why Measured by Chemical Property of Cur- rent, 14, 17 of Magnetic Field, Definition of, 79 ■■ Relative, of Different Parts of Magnetic Field, Comparing, 79 Steel Filings for Magnetic Lines of Force Diagrams, Preimration and Use of, 71-76, 77, 565 Straight. Line Calibration, How Ob- tainable in Galvanometers and Ammeters, 126, 182, 187, 147 Substitution, Simple, Method of Com- paring Resistances, 285 Sulphate of Copper. (See Copper Sulphate.) of Mercury. (See Mercurous Sulphate.) — •— of Zinc. TAN ^639 fiwitch-BoMd, tteicnry, Method of AToiding Possibility of Short-Clrciiiting when Using, 640 — for Making Two Sets of Ck>nnec- tions, 286 Symbolieal HepreMntation of Bat- tery, 237 Hynchronised, BeflniUon of, 888 Table I., Electrochemical Equivalents of Copper per Second per Ampere, 28 II., Specific Gravities of Mixtures of Sulphuric Acid and Water, 89 III., €k>nstant for Tangent Galvanometer for ld. 1891- 1900 104 IV., Baiios of Practical Units of Resistance, 174 v., Ratios of Practical Units of Potential Difference, 175 VI., Variation of Specific Resist- la ance with DenslVi for Oopper, 268 VII., Poriflod Substances in Order of Increasing Resist- ance for Same Length and Sectional Area, 269, 260 VIII., Purified SubBtaaoes in Order of Increasing Resist- ance for Same Length and ' Wek;ht, 261 IX., Percentage Variation in Resistance per 1*0., 266 X., Specific Resistances and Per- centage Temperature Varia- tion of Materials Uned in Constructing Resistance Coils, 271 XT.^ Approximate Relative Conductivities per Cubic Unit, 276 XII., Weights of Materials Con- sumed in Cells per Hour per 1,000 Amperes, 484 XIII., Weights and Cost Of Materials Consumed in Cells ger Board of Trade Unit reduced, 486 Showing Development of Electrical Transmission 6f Power, 412 Tables Showing Connecti^ between ESfliciencv of Transmission, and Ratio between Power Received to Maximum Power Receivable, 414, 416 Tangent of Angle, Definition of, 88 Galvanometer, 88 — ^Galvanometer, Axis of Needle and Plane of Coil of, Test for Parallelism between, 83 Galvanometer, Calibrating Any Galvanometer by Comparison with, 108 Galvanometer, Calibration Curve of, 84 Galvanometer Coil Giving Greatest Sensibility, 100 Galvanometer, Coil of, Adjust- ing, 85 Galvanometer, Coil of, Why Circular, 107 Galvanometer, Coil of. Why Large, 99 Galvanometer, Constant for a.d. 1891-1900, 104 Galvanometer, Total Controlling Force on Needle, 104 Galvanometer, Deflection Best Used with, 90 Galvanometer, Deflection of, in Amperes when Controlled only by Earth's Magnetism, 108 — Galvanometer Deflection of, and Current, Connection be- tween, 88 Galvanometer, Detailed Descrip- tion of, 49 Galvanometer, Disadvantages of, 106 Galvanometer with Needle Strongly Magnetised, Ad- vantages of, 91 Galvanometer, Scale for. Con- structing, 87 Galvanometer, Sensibility of, Experiment Showing Law and Variation, 100 Galvanometer, Sensibility of. Independent of Length and Strength of Needle, 91 Galvanometer, Sensibility of. Inversely Proportional to Diameter of Cou, 98 — :- Galvanometer, Sensibility of, Method of Increasing. 91, 98 Galvanometer, Sensibility Pro- portional to Number of Con volutions of Wire, 98 Galvanometer, Sensibility of, RestrictionB in Increasing, 98 Galvanometer. Sensibility o^ Varies with Strength or Con* trolling Field, 102 640 TAN VUACnCAh BLBCTBICITT. TJNI Tangent Law, 91 • Law Bxperirocntally Tested, 92 Principle, When Applicable in Galvanometers, 8i Telegraph Llnep, Fanlt TestinK in. by Bright, Siemens, and Yarley, 569 Lines, Several Worked with One Battery, 527 Telegraphy, Cells Best for, 527 Use of Accamalatora in, 627 Temperature Coefficient and Specific Resistance of Materials, Re- lation between, 267 — — Coefficients of Resistance of Metals and Alloys, 264-267 Variation, Effect of, in Daniell's Cell, 436 Variation of E.M.F. of Claik's Cell, 476 Variation of Resistance of Materials Used in Resistance Coils, 476 Variation of Resistance with, 262-271 Terminal, Positive, of Cell, Definition of, 376 Terminals of Cell, Potentials of. Re- latively to Earth, 876 of Cell, Signs of; 376 Tliermo-pile, Use of, for Conversion of Energy, 868 ; Note, 563 Thomson, Measurements of Heats of Combustion by, 478, 481 Thomson Joulemeter. (6'ee Joule- meter, Thomson.) Tin, Relative Electric and Heat Con- ductivities of, 275 ^— IlcHistance of, per Centimetre Cube and per Inch Cube, 259 Resistance of, per Foot and per Metre Weighing One Gramme, 261 Resistance, Percentage Varia- tion of, per I'C, 266 Torque, Definition of, 44 Coil with Maximum, under Given Conditions, 148 Ti-ansmission. Commercial Efficiency of, 400 Electric, of Energy, 352 — — Electric, of Power, Conditions for High Efficiency of, 410 Electric, of Power, rower Lost in Overcoming Resistance of Circuit, 410 — Electiic. of Power, Table Show- ing Development of, 412 ——Electric, of Power, Using High P.D. in, 412 Tranmi8sioB,Eleetrica] Efficiency ot 409 ——Electrical Efficiency of, and Ratio of Bower Received to Maximum ewer Receivable, 412 '^ — of Bnei:gy tr^m Generator, Mechanical Model Illustra- ting, 855, 85Q of Energy, MethOdis of, 852, 354, 856, 857 Tungsten, Addition of, to German Silver, 268^ Two-Fluid Cell, 423 Uniform and Constant, DifTerence between, NoUt 153 Magnetic Field, Arrangement for Neutralising, 78 Magnetic Field, Definition of, 70 Unit, B.A., Definition of, 573. (See aigo Unit of Resistance, B.A.) Board of Trade, Cost of Pro- ducing, 488. 491 Board of Trade, Cost of Pro- ducing with Battery, Con- ditions Governing, 482 Board of Trade, Dehuitiou of, 849 ' , Board of Trade, Price of| 349 Board of Trade, Value of, in Watt Hours, Joules, ^i-gs, Foot Pounds, and. (See also Unit, Board of Trade.) of Force, Dyne, Note^ 317 of Force, Gauss's Absolute, 671 of Heat, 818 of P.D., Absolute Electro- magnetic, Definition of, 576 toNi iNDBlt. VOL 641 tJnit of F.D., Absolute Electromag- netic, Volt in Terms of, 479, 676 of P.D. '^i.A., International, and Legal, in Terms of Each OthuT, 176 of P.D. and Pressure between Terminals of Clark's Cell, 68P, 694 — :■ of P.D., Volt, DeEnition of, 174, 576, 678, 688, 688, 689, 590, 693. (See al8o\olt.) of Power, 826, 327, 691 of Power, Watt, in Terms of Other Units of, 826 of Pressure. (See Unit of P.D.) of Quantity of Electricity, 579 of Resistance, Absolute, History of, 668-600 of Resistance, Absolute Electro- maguetic, Method of Deter- mining, 678 of Resistance, Absolute Electro- magnetic, Value of Siemens' Unit and Ohm in Terms of, 678, 691 of Resistance, B.A., Aim in Choosing, 676 • of Resistance, B.A., Deilnition of, 673 of Resistance, B.A., First Indica- tion of being Too Small. 576, 677 of Resistance, B.A., Rayleigh's Value of, in C.G.S. Units, 680 of Resistance, B.A,, Inter- national, and L^al, in Terms of Each Other, 174, 687 of Resistance, Ohm, Definition of, 178, 678, 683, 687, 691, 698. {See also Ohm.) of Resistance, Siemens', 570 of Self-induction, 690 of Work, 817, 849, 591 of Work, Joule, in Terms of Foot-Pounds and Ergs, 317 Magnetic Pole, Definition of, 669 Units, Absolute Electromagnetic, 479, 578, 676. 676, 683, 591 C.G.S. , Adopted for Electrical Measurements, 676, 678, 683, 587, 593 — Electrical, Committees to Con- sider, 672, 678, 679, 681, 684, 687, 588, 690, 692 Electrical, History of, 24, 174, 668-600 Electrical, Legislation of, 692 Universal Shunt. (See Shunt* Uni- versal.) Absorbing in Instruments, I Vapour, Device for ' Electrostatic 198, 217 Varnish, Conducting Transparent, Composition of, 200 Conducting Transparent, Use of, 166, 192, 199 Vibration of Gomi«ss Needle, Con- ditions Governing Rate of, 79 of Pendulum, Rate ot. 886 of Pendulum of Clock-Joule- meter. Varying Rate of, 886 Vitreous Electrification, Definition of, 161 Volt, B.A., Definition of, 676 Board of Trade, Definition of, 588, 589, 693 International, Definition of, iTi^ 591 Legal, Definition of, 683 B.A., International, and Legal, in Terms of Bach Other, 175 Board of Trade Standard, 696 International, and P.D. between Terminals of Clark's Cell, 589, 694 in Terms of Absolute Blectio- magnetic, or C.G.S. Unit, 479, 676, 678, 698 Voltaic Element, Simple, 869, 418. (See dUo Simple voltaic Ele- ment.) Voltameter, Copper, Chemical Action in, 20 Copper Deposited per Second per Ampere in, 29 Copper, Description of, 10, 17 Copper, Used for Measuring Large Currents, 26 Direction of Current in, 38 Hofftnann's, 31 '' Silver, Definition of, 695 Silver Deposited per Second per Ampere in, 28, 27, 696 Silver, for Measuring Cummts of about one Ampere, 23, 596 Silver, Method of Making a Measurement with, 25, 694 Silver, Preferable for Measuring Small Cun'ents, 28 Sulphuric Acid, 10, 17. 81, 39 Sulphuric Acid, Chemical Action in, 20, 82 ; NoU, 62 Sulphuric Acid, Objection to Usual Mode of Constructiog, 88 Sulphuric Acid, Practical Forma of, 89-42 642 VOL PRACTICAL BLBCTRICITY, WIN Voltameter, SiUpharic Acid, for Meas- uring Time to Produce Given Volume of Gas, 41 Voltameters and Galvanometers, Re- lative Advantages of, 42 Only Used in Measuring Large Currents, 42 - Voltmeter and Ammeter, Measuring Resistance with, 185, 282, 866, 492 and Ammeter, Measuring Power with, 828 '— and Ammeter, When Impossible to Measure Power with, 828 and Ammeten Measuring Vari- able E.M.F. of Current Generator with, 869 Ammeter Used as, 179, 181 Ayrton and Mather Zero Elec- trostatic, 164, 181 Calibrating, by Using Potentio- meter, 610 Connecting, in Circuit, Method of, 182 Current^ Result of Disconnectr ing, 181, 188 Current, Result of Short-Cir- cuiting, 181. 182 Definition of, 179 Deflectional, Calibrating, 183 Determining E.M.F. of Cell by, 479 Electrostatic, 164, 179. 181 Enclosed in Conducting Case, 198 — ^ Graduating, by Potentiometer Method with Clark's Cell, 616--519 High Resistance, When Used, 181, 862, 866 "Ja Ja" Wire Used in, Note, 813 Low Resistance, When Used, 181 Measuring E.M.F. of Cell by, 862, 865 Moving CoU, 188 Part of Wattmeter Acting as, 830 Scale, Potentiometer Method of' Testing Accui-acy of, 510 --^ Sensibility of. Bridge, Wbeatstone's.) Proposed IJnit of Resistance, 569 Resistance Coils, Earliest Form, 669 "V^fiedemann, G., Ohm Determined by, 582 Wild. Ohm Determined by, 582 Winding Resistance Coils, Mode oL 280 of. by. (Ses WIR INDEX. ZIN 643 Wire, Subdivision of, into Lengths having Equal Resistances by Foster's Method, 518 Used in Resistance Coils, Com- Sosition and Gauge of, 280, 32 Used in Resistance Coils, Neces- sity for Small Temperature Variation of, 280 - Wires Tnth Current Flowing, Action on each other, 8 Work Done by Current, 818-316 Electric, Unit of, 817, 849, 601 Z Zero Electrometer of Ayrton and Mather. 164, 181. ^ee also Voltmeter, Zero Blectaro- static.) Electrostatic Voltmeter. (SeeVolt- meter. Zero Electrostatic.) Type of Electrometer, 168 Wattmeter, 880 Zinc, Amalgamated, Advantage of Using, in Cell. 429, 430 Amalgamated, Theories as to Action o^ 480 Amalgamating, Method of, 429 Atomic Weight of, 27 — — for Clark's Cell, Preparation of, 468,597 Commercial, Result of Using in Cells, 429 Consumed in Cells per Board of Trade Unit Produced, Weight and Cost of, 465, 486 Consumed in Cells per Hour per 1,000 Amperes, 424, 440, 484 Zinc Deposited per Second per Am- pere in Voltameter, 27 Effect of Adding to Mercury, 480 Electrochemical Equivalent of, 27 Plate of Cells, 419, 428, 431, 483, 485, 488, 445, 450, 454, 455 458, 459, 460, 461, 462, 468 (See also Plate of Cells.) Plate of Cell in Form of Cylin- der, 431, 455, 461 Plate of Cell in Form of Pot, 458, 459 Plate of Cell in Form of Rod, 450, 454 ' Resistance of, per Centimetre Cube and per Inch Cube, 259 Resistance of, per Foot Grain and per Metre Gramme, 261 Resistance, Percentage Varia- tion of, per 1°C., 266 Oxide, Possible Formation of, in Simple Voltaic Element, 419 Sulphate, Formation of, in Simple Voltaic Element, 419 Sulphate Formed per Hour per Ampere in Daniell's Cell, 425 Sulphate Formed per Hour per Ampere in Grove's Cell, 440, 441 Sulphate, Heat of Formation of, 478, 481 ' Sulphate Solution for Clark's Cell, Preparation of, 468, 471, 597 Sulphate, Variation of Resist- ance and E.M.F. of Grove's Cell with Production of, 441 Printed by Cassell & Company, Limited, La Belle Sauvage, London, E.G. ».97 C- O. 