None
Higher Part* of Soale, Cftlibntion of, b/ Sine Method. 85 Potential, Definition of, 85 Hoffknaun's VoltMneter, 15 Holts's Influence Electrical Ma- chine, 867 Hoopar'a YnloaniMd Indiarabber, BesictADoe of, 271 Horisontal Component of Magn«rtic Force, Uon of, noUt 55 Horae-Power. 201, 448 Hydxogem, Specific Indactire pacitjr of, 8I0 Hypotannae, Definition of, iiot«, 87 Earth's Dafini- Ca^ TLLUMIFATIN'O Power of Arc ''' Lf mp <, Measoring, 454 Power o. Arc Lamps in anj Plui.c, Meaanring, 457 Power of Incandeacent Lampa, Measuring, 458 Image, Connection between Motion olf OD PUne Scale and Angnhur Defiection of Mir- ror, 107 Incandeacent Lamp, Deacription of, 4&1 — Lamp, Measuring Effldencj of, -~— Lamp, Measuring TUnminating Power of, 458 -^Lamp, EfSciency and Life of, 458 Indiaruboer, Resistance of Hooper's Vulcanised. )t71 Specific InductiTe Capacity of, 810 Indication of Direction of Current in Magnifying Spring Am- meters and Voltmeters, 389 Induction, Definition of, 07 and Conduction Compared, 97 Self. 174, 487 Inductive Action, 87 Action between Conductors of DifiTerent Potentials, 87 Capacity. Specific, 309 Inefficiency of frictional Electrical Machines, 358 Inertia, Definition of Monant of, fi ota, 78 Infinity Plug, 151 Influenoo Machine, Adjusting Balls of, to Produce Giveu Majd> mum Potential Diflierence, 872 ■-— - Machine, Attaching Leyden Jars to Colloctora of, 370 — — Machine, C^trnpound Interest lAW of , 364^ 81 In Infloence Machine, Condanaen for Urn with, 318 — Machine, Distance Spark can ba sent between Baila of, STU Machine, Work done by, 371 Machine, Bertach, 981 Machine, Accrumnlating, 361 ; Holtx'a, 807; Nicholaon'a. 886; Thomaon'a. 364 ; Var- Wa, 367; voea, 367; Wimahurst, 867 Parallel, Wirea Joined. Deflni- tionof,IS6 In Seriea, Wirea Joined, Definition of, 140 Instmetiona for Experimesxta, Sp^' oimena of, 476 lustxnmenta, Commercial, for Mea- suiin? Current, 79, 876 InsnlatingStand, Conatruetion oU Sterna, Coating, with Paraffin Wax or Shell-lao Vamiah, 867 — Varnish, How to Make, MfoU, 268 Insulation, Importance of Good, and Mode of obtaining, in Delicate QaJTanomeUKB, Insulator, Definition of, 0 Insulatora, Diminution of anoe of, with Increase of Temperature. iSTl Obtainable for Eleetricity, not for Beat, 158 Table of Resistancea of, 271 Tele^ph, 274 Teating, during Mannfsctnra, 275 lutematiooal Electrical CongrenL Unit of RealBtuui'e Adopted by, 140. 141 Interpolation ot Resulta by Means of Curve, 84 Invariable Abaolute Calibrataon, Qalvanometers with, 57 Iron Box, Partial Magnetic Screen, 101 Change of ReaiKtanoe of, with Temperature, 160 — Electric and Heat CondnetiTl> tiea of. Compared, 150 Resistanoe. of for Qiven Length and Diameter, and for Given Length SAd Weight. 157 Reaistanoe of, per Cnbic Centi- metre, and per Cnbio Inoh, 154 -^Corea, Use of, in Galvanoi teca.78 INDEX. 503 iMMi Magsetiflod Ij Electrlo Cur- rent, 8 Coils. Id2 JAB, linden, 314. (&• also Ijey- Used for DioiieU'fl CeU, 210 Joints, Lap and Butt, 79 Jonle, I>emiitlon of the, 461 Joule's Mechanical Equiralent of Heat, 801 T?^MPE'8 Constant Total Current -^^^ Shunts, 257 Key, Bridge, 174 Charge and Discharge, 320 Charge and Discharge, Simple farm of. 343 -^— Charge and Disohaige, Various Modes of Connecting, with Condenser, Battery, and GalTanometer: 320—322 -^— Make and Break, Simple Form of, 19 PlasN Description of. ISO Kxrehholrs First Law, ^6^ Second Law, 4S4 T JLI<Ain>E Chaperon Cell, 210 Lamps, Description of Arc and Incandescent, 454. {See also Arc, Incandescent.) Lamps Used with Befleoting Qalva- nometer, 105 Lap Joint, 79 Large Potential Differences, Pro- duction of, 351 Latimer Clark's Cell, 410 Clark's Cell, Constancy of E.H.F.of,411 Clark's CelL E. M. F. of, 411 —. Clark's Cell, Temperature Va- riation of E. M. F. of, 411 — ^ Clark's Differential Ghilvanome- ter,150 Law connecting Two Seta of Facts Determined by means of Curre, 35 — ^of Differential Oalnmometer, 140.183 — Experimental Proof of Ohm's, 180 Kirchhor B First, 464 Kirchhoff's Second, 464 -- — Ohm*8,190 — — Tangent, FnliUment of Condi- tions for, in Tangent Oal- ▼anometer, 43 Law, Tangent, When True, 41 Sine. When True, 61 of wheat8tone*8 Bridge, 167 Laws of Surface Leakage and Leak- age through the Mass, 270 Lead, Change of Resistance of, with Temperature, 160 Electric and Heat Conducti- yities of. Compared, 159 — • Besistance of, for (JiTen Length and Diameter, and for Given Length and Weight, 167 Besistance of, per Cubic Centi- metre, and per Cubic Inch, 154 Leakage, Dependence of Bate of Loss of Charge from, on Dielectric Only, 343 Surface, 266 Surface, Law of, 270 through the Mass, 266 throng the Matis, Law of, 270 Leclanchtf Cell, 220 Cell, Chemical Action of, 221 Cell, E. M. F. of, 222 Legal Ohms and B. A. Units, Equa- tion Connecting, 142 Unit of Besistance, 140 Length, Variation of Besistance with, 143 Lens, Definition of Focal Length of, 466 Mode of Using, with Befleoting Galvanometer, 104, 105 Levels, Spirit, for Beflecting Gal- ▼anometer^ 285 Leyden Jar, Attachmg, to Collecting Combs of Electrical Ma- chines, 370 Jar, Construction of, 314 Jars, Battery of, 317 Life of Incandescent Lamps, 458 Ligbt, Measuring Efficiency of Elec- tric, 452 Measuring Illuminating Power of Electric, 452 Lines of Force, Deflnition of, 43 Liquid and Wire Beaistances, Com- parison of Use of, 194 Decomposed by Electric Cur- rent, 8 Saturation of, note, 411 Supersaturation of, noU, 411 Liquids, Difference of Level in. Com- pared with Difference of Potential, 86 Local Action in Cell, 217 Action in Daniell's Cell, llow to Preventk 217 504 PEACTIOAL BLECTRICITT Tiockwood Cell. 818 Logarithmio Deorement, 296 Decremeut, Determlnatloii of, when Damping is Very 81ifbt.897 Lord Bayleigb, SUrer Voltainefeer UMdby, U M llf ACHIVES, ElMtrioil. Adjust- '^"- ing Balls to Prodnoe OiTon Potential Diffeieace, 872 Eleotrioal, Attaohing Lejden Jura to CoUectora of. 370 — Electrical, Ocmdensers for Use Willi, 818 Electrical, Frictional, 898 •^— Influence, Bertseh's, 861 — Inflaence, Aocnmnlatiuff, 861 ; Holts, 867 ; NicholKon's, 866; Thomson's. 864; Yar- Wimsliarst, 867 ^^luflnenoe, Aocmnalating, Con- densers for Use with, 818 ^^ Influence, Accumulating, Com- pound Interest Iaw of, 864,866 Influence, Accumulating, Work done by, 871 Magnet, Connection between Poles of, and Direction of Cur- rent round, 17 Definition of North-Seeking End of, not«, 16 Deflected by Current, 8 Electro. (SMElectro<lCagnet.) ^— Motion of, Produced hj Uni- form Magnetic Field, 880 — — Permanent, Measurement of Distribution of Magnetism in, 84 — ^ Permanent, Prcm<ntional Gktl- Tanometor Controlled by, 78 Magnets, Position of Poles In, 28 Magnetic Axis of Needle, Definition of, 87 Disturbance, Shielding Galva- nometers from Extraneous, 67, 78, 108, 880 Effect of Bobbin, Variation of, with Current and Besist- ance, 418 — ^ Field, Motion of Magnet pro- duced by Uniform, 880 ■^— Force, Definition of Horisontal Component of Earth's, note, 55 •^ Force, Direction of. produced hj Current in Flat Coil, 48 MJeridian, Plane of, naU, 45 Property of Curreot, Uses of, 4 Saturation, 888 Screen, Thick Iron Box, 101 Magnetised, Ironi, by Current, S Magnetism, Measurement of Dis- tribution of, in Permanent Msgaefc,84 Besidnia, Definition of. Wire in, 4fil Making Sine Scale, Mode of, 68 Tangent Scale, Mode of, 38 Mance's Test for Besistanoe talning E. M. £\, 470 Marine Galvanometer. lOB Galvanometer, Fibre sion used in, 60 Galvanometer, Shielding, from Magnetic Disturbanoe, 108 Mass, Law of Leaka«^ through, 870 Leakage through, 266 Material for Outside Hesistanoe for Voltmeters. 428 for Wire for Voltmeter Coilay 420 ^— used in Besiscance Coils, 159 Variation of Besistanoe with, 146 Mather's Mode of Calibrating Gal- vanometer with Constant Current, 67 — — Proportioiial Galvanometer with Uniform Controlling Field, 72 Beflecting Galvauometer, 280 Matthlessen's Equution Connecting Besistanoe with Tempera- ture, 158 Experiments, Tables deduced from, 154, 157 Finding, by moiiifl of Cnrveb8M IKDEX. 500 MaxlutaB Potential DifferoDce of £lectxical Macbine, Deter- minatioii of, 372 •— Usefnl Power, Current tbnt I>eTelop8, 448 — — Useful Power in Generator with Fixed E. M. F. and HesistaDoe, Current tliat DeTelops, 448 Meaaaring Arc Light, Efficiency of, 455 —— Arc Ijight, lUaminating Power of, iu anj Plane. 457 ~— > Arc IJight, Illuminating Power of, How to Overcome Dif • ferenee in Colour between it and Candle when, 457 -^ EfBcienoyof Electric Light, 452 — — Efficiency of Licandeaoent Light, 45B Current, Altenmting, 196 >— - CtLrrent, Commercial Instru- ments for, 79, 376 —^ Current by Bate of Production of Heat, 197 '— Current with Siemesis' Dyna- mometer, 379 — ~- Small Currents, Disadvantaire uf using Voltameters for ,20 • Strength of Current, 4 Distribution of Magnetism in Permanent Magnet, 24 Electric Density by means of Proof Plane, 117 — — Electn>motive Force of Cur- rent Qenerators, 224, 2?1, 284,841. (Sm also Electto- motive Force.) — — Potential Difference by Weigh- intr, 88 — ' Potential Differences, Alter- nating, 426 -— Potential Differences, Static and Current Methods of. Compared, 125 -■^— Power 442 Besistance of Batteries, 205, 225 Besistance of Batteries using Known Besistances, 226 ^»- Besistance of Batteries using Known Besistances aud Sbunt, 226 — - Itesistance of Current Gener- ator, Condenser Method of. 842 •— - Besistance by Bate of Loss of Charge, 844 — ^ Besistance by Bate of Loss of Charge, Galvanometric Method of, 848 «— — Besistance Containing B.M.F., 460 Measuring Besistance durincr "Pa sage of Strong Current, 187 High Resistances, 277 Specific Inductive Capacity, Qoantity of Electricity, 111, 280.299 Measurement A.b8oIute, of Capa- city, 827 — <rf Po.e..uai Compared with Measurement of Tempera- ture. 85 Mechanical Equivalent of Heat, 201 Meidinger Cell, 212 Mercury, Change of Besistance of, with Temperature, 160 Besistance of, for GiTcn Lenffth and Diamet-^r, and for Given Length and Weight, 157 — Besistance of, per Cubic Centi- metre, and per Cubic Inch, 154 Meridian, Definition of Plane of Magnetic, note, 45 Metal having Least Change of Be- sistance with Tempera- ture, 160 Metals, Change of Besistance of, with Temperature, 160 Electric and Heat Conducti- vities of. Compared, 159 —•^ Besistance of, for Given Length and Diameter, or for Given Length and Weight, 156 — — Besistance of, per Cubic Centi- metre, and per Cubic Inch, 153 Metallic Case, Necessary Enclosure of Electric Apparatus in. 108 Meters, Electro-Magnetic Control, 392 -^Electro-Magnetic Control, Crompton and Kapp's, 392 -«» Electro-Magnetic Control, Pa- terson uud Cooper's, 893 — . Electro-Magnetic Control, Ad- vantages of, 394 -^ Electro - Mafrnetic Control, Disadvantages of, 894 Gravity Control. 891 — — Spring Control, 377 Spring Control, Cunynghame's, 882 ; Magnifying, 886 ; Siemens', 377 Meters. {Sm also Ammeter. Dyna- mometer, Ghklvanometer, Photometer. VoltmeteTi Wattmeter.) Metre Bridge, 168 Mica, Betdstance of, 271 506 PEAGTIGAL ELBCTRICITir. Miom CapaoitT Spedflc IndnetiTe of, 810 ICiciometer Sciew, DeMsriptlon of, not*. 24 Bfinotto's Cell, 8U Xixror, Angular Mation of. Half that of Befleoted Saj-, 103 — — Consection between Angnlar Deflection of, and Motion or Image on a Plane Soale, 107 —-in OalTaaometer, Use of, to Avoid Parallax, 88 forB«flecting(}alyanometer,I05 Moment of Couple, Definition of, not«, 883 of Inertia^ Definition of, nota, 78 Motion, Angolar, of Befleoted Bay, 106 -^ of Image on Plane Scale, Con- nection between, and Angu- lar Deflection of Mirror, 107 of Magnet produced by Uni- form Magnetic Field, 890 Multiples of Obm, Gonatruotion of, 145 Multiplying Power of Shunt, 178 Power of Shunt used in Meaauring a Discharge, 810 N De- ^APIERIAN Logarithmic -^^ erement, 896 NegatlTe Chaigs)>f Ebonite Eleetro- phonu Armnged to Give, 859 ^— Electrioii7, 85 Network, Currents in, 468 Kicholson's BeTolring DouUer, 866 Nickel, Besistance of, per Cubic Centimetre, and per Cubic Inch, 154 North-seeking end of Magnet, Defi- nition of, not«, 16 Nought, Potential of Earth Arbi- trarily taken as, 84 Null Methods, Meaning of, 886 O r)HM, 89, 140. 141 ^^ Construction of Multiples of, 14ft Definition of Jjeffl, 140 <— Only Electrical Unit yet Legal- ised,140 Ohmmeter, Description of, 190 Ohms, Legal, and B. A. Units, Equa> tions connecting, 148 Wires having BefiisUmce of about Ten, 143 Ohm's Law, 180 Law, Experimental Proof oC, 190 defiant Gas, Specific Indnctivo Gapacil7 of. 310 pABAFFIN WAX. Coating In- -^ snlating Stems with, 867 Wsz, How to PreVent OTer^ heating when Melting, not*, 207 Wax, Besistance of, 271 -— Wax, Specific IndnotiTe O^ta- city of, 810 Parallax. Definition otnatB, 88 Mirror Used in Galvanometer to AToid, 88 Panllel. Cells in. Figure oi, 889 Cells in. Symbolical Bepre- sentation of, 840 Circuit, Wires Joined in, 136 Circuit, Independence of. Cuxw rents in, 860 E.M.F. ofCeU8in,841 Besistance, 179 Patenon and Cooper's Electro-Mag- netic Control Meters, 8ftS P. D, Meaning of, 280 Periodic Time of Vibration, Defini- tion of, 891 Permanent Magnet, Proportional Galvanometen Controlled by, 78 Magnet, Measurement of Dis- tribution d Magnetism in, 84 Magnet Meters, 69 Magnet Meters, Advantages of, 78 Magnet Meters, Direct-Bead- ing. 76 — Magnet Metors, DisadTsatage of, 876 -^Magnet Meters, Proportional, 71 Photometer, Dispersion, 454 Bumford's, 4SS PiYOt and Fibre Suspensions, 60 Plane of Magnetic meridian. Defini- tion of, HOIS, 45 Proof, 116 Platinoid, 160 Besistance of, 161 Besistance, Coils of. 161 Platinum, Electric and Heat Con- ductivities of. Compared, 159 Besistance of, for Given Length and Diameter, and for Given Length and Welgbtk 127 INDES 607 Centimetre* and per Cubic Inch. IM BilTer Allor, Change of Besist- anoe of, with Temperatoie, 100 — ^ SilTer AUoy, Besiatanoe of .for Given Length and Dia- meter, ana for Given Lengrth and Weight, 157 — — Silver AUoy, Beaiatanoe of per Cubic Centimetre, and per Cubic Inch, 154 Phiir>Jnflnit7, 151 — K^, DeMrnption of, 138 Beaistanoe Sozea, Conatruction of. 151 Ponrendorff's Method of Compar- iug E. M. Fa.. 231 Method, Uae of, for Calibrating Voltmeters, 413 Polariration of Daniell'a Cell, 216 of Latimer Clark's Cell, 4U Polea of Magnet, Connection be- tween, and Direction of Current round Magnet, 17 of Magnetfl, Poaitions of, 23 Portable Electrometer, 83 Ghalvanometer with Approxi- mate Absolute Calibration, 68 PooitiTe Electricity, 85 Potential, 85 Potaah Bichromate Cell 222 Bichromate Cell, Ciiemical Ac- tion in, 223 Bichromate Cell, Compoaition of Liquid for, 222 Bichromate Cell, E. M. F. of, 223 Bichromate Cell, Form of Zinc for, 223 Potential of Conductor Compared with Pressure of Gas, 121 -—of Conductor, Ways in which it can be Varied, 121 — ^ of Conductor Depends partly on Amount of Electeicity on it, 110 ——of Conductor Depends partly on its Position, 119 -~-of Conductor Depends partly on its Shape, 119 — — Density, and ^Q&ntity, Exam- ples showing Differenoe be- tween, 121 ->— Difference, 80 ••—Difference, Adjusting Balla of Electrical Machine to Pro- duce Given Maximum, Potential DiflSarence, Alternating, Increases Practical Besiat- ance of Voltmeters, 427 Differenoe, AltematingfMeaaur- ing.426 Difference between Two Con- dnotora does not Measure Differenoe in their Electric Charges, 85 — Difference between Two Points in Uniform Conductor Con- veying Current Propor- tioDalto Distance between Pointa, 83, 143 <-^- DiOereaoe, Charges on Two Conductors Vaiy as, for Constant Belative Posi- tions, 103 Differenoe Compared with Dif- ferenoe of Level in Liquida, 86 Difference Compared with Dif- ference c€ Pressure in Gases, 86 -~- Difference Compared with Dif- ferenoe of^ Pressure of Water Flowing in Pipe, 80,81 Difference, Contact, 351 — — Difference, Distance and At- traction between Two Par-. Poioitial I>Ufat«iioe Beqnind to Produoe Spark between Two MetRllio Balls, S70 — ~ DUBerence, Statio and Cuient Kethod of Meaaoring, Compared, 125 —— Dlfferenoe, Snb-diTidinjr into Known Fimctiona, 2^ — Difference, Variation of, at Bat- tery Terminals, with Varia- tion of Cnrrent, 804 — Difference. Variation of, with Besistanoe of Gireu Volt- meter to Prodaoe Oiren Deflection, il9 — — Higher, and Lower, Poeitire, ana NegmtiT^ Definition of, 85 — — Increasing Sensibility of Weight Electrometer by Using Auxiliary High, 91 ^— Inside Closed Condootor, 96 ^— Measurement of, Compared with Measnrementof Tem- perature, 85 ^— ' of ifarth Arbitrarily taken as Nought, 84 Uniform on Conductor. 88 Uniform in Conductor, 98 Power, Arrsngement of Cells Qir- ing Maximum Useful, to Conductor of Fixed Beaist- anoe, 450 — ~ Cazrent DcTeloping Maximum Useful, with Generator of Fixed E. M. F. and Besist- anoe, 448 Deflr>ti<>n of, 441 -— — Distribntioo of, in Circuit. 445 — — £. M. F. used by Deprez hi Transmitting, 87 Miles, 452 Horse. 201, 443 — Measurement of, 442 Ui.it of, 442 -»- Utilised in arcuit Outside Ge- nerator, 445 •— — Wasted in Heating Generator, 446 Prepaxat'on of Varley's Carbonised Cloth, 897 Pressure, Difference of, in Gases, Compared with Difference of Potential, 88 — of Gas Compared with Poten- tial of Conductor, 121 — — of Water, Difference of. in Pipe Compared with Difference of Potentials, 81 Proof of Ohm's Law, Experimental, 180 Proof-plane, lU Proof-plane, Denaity by means of, 117 Properties of Electric Cnm«nt, 3 -~— of Electric Current, Frscticsl Uses of, 4 Proportional Coils of Wheatstone's Bridge, 172 Galvanometer, 71, 7S, 106, 389 Proportions of Channel in Bobbin of 'nmgent GalTanometer. when rnngent Law is Most Accurately Fulfllled. 51 QUA DBANT Electrometer, Thom- son's, 03 Electrometer, Edelmann's Mo- dification of Thomson'Sa lao Electrometer, Edelmann's Mo- dification of Tnomson'a, Defects in, 134 Electrometer, Edelmsnn's Mo- dification of. Dry Pile for, 133,872 Electrometer, Edelmann's Mo- dification of. Needle for, 132 Electrometer. Formula for, 134 Quantities of Electricity, ComiAri- son of. 111, £99 Quantity of Electricity, Definition of, 109. (Sm also Charge. ) of Electricity, Unit of, 2^9 of Electricity Produced by Rubbing Two Bodies To- gether, 118 Potential, Density, Examples showing Difference b«»- tween. 121 Unit of, 289 R PADIATION of Heat, ExplanatfoM ^ of, fiots, 195 Bate of Loes of Charge. Measuring Resistance by, 84ft of Production of Heat in Gal- Tanometer CoiLl ^ of Production of Heat, Mo»> suring Current by, 197 Ratio of Potential Difference to Current Constant with Given Conductor, 130 of Potential Difference to Cuxw rent is the Resistance, 190 — of Sensibilities of Commuta- tor Ammeter in ParalliC and in Series. 4S1 IKDEZ. 509 Batlo off Senilbilitiea of Yoltmeter in Parallel and in Series, 433 Rajrlel^h, I.ord» Silver Voltameter Used by, U. 305 •— Lord, Temperatoro Ynnation of £. M. F. of Clark's Cell Determined by, 411 BAOordinsr Results of Experiments Graphically, 90 — — S«eult8 of Experiments Gra- phiciilly. Value of Curves for, 33 Befleeted Bay, Angular Motion of,106 Reflecting (ialvanometer. 108, 281, k93, 209. {Set also Galva- nometer, Reflecting.) — . Galvanometer, Different Ways of Forming Image with, 105 Galvanometer, Lamp Used with. 106 Galvanometer, Modes of Using Lens with, 105 — — Galvanometer, Spirit Level for, 285 Relative Calibration of Galvano- meter, Meaning of, 22 Relatively Calibrating Galvanome- ters, 27 Replenisber, Thomson's, 364 Repreaeutation of Batteries, Sym- boUcal, 173, 240 Reaidnal Magnetism, Definition of note, 388 — - Magnetism, Testing Ammeters for, 400 Resin, Sped Ac Inductive Capacity of, 310 Besiflitance, 9, 129 —— Amount of Heat produced per Minute by Given Current flowing through Given. 190 »— and Current. Variation of Mag- netic Effect of Bobbin with, 418 ^"-^ Apparent Increase of, in Gal- vanometer, Due to Damp- ing 340 of Battery, Measoring, 205, 225, 342 Best, for Differential Ghilvano- meter, 436 ^— Best, for Galvanometer in Sim- ple Cirouit, 485 ——Best, for Gktlvauometer of Wheatstone's Bridge, 172, 466 —— Best, for Coils of Wheatstone's Bridge, 171 — Best, to Give to Galvanometer, 435 -^— Box, Description of, 28 — Box, Constmotion <x Plug, 151 1 I Box, Constmctioii of Sliding, 186 Box used in Duplex Telegraphy, 187 Resistances, Calibrating Galvano- meter by Using Known, and Constant Potential Differ- ence, 164 Oalibrating Galvanometer by Using Known, and Cell <n Constant E. M. F., 238 — — Change of, with Temperature, Results of Matthiessen's Experiments on, 160 -—~ Comparing, 136 Comparing, Differential Galva- nometer Method of, 148 Comparing, Potential Differ- ence Method of, 140 — Comparing, Simple Substitu- tion Method of, 138 ' Oomparing, AVheatstone's Bridge Method of, 166 Oomparing Use of Liquid and Wire, 194 Resistance Containing £. M. F., Measuring, 460 Coils, 28, 145, 151, 153, 159, 163 Coils, Accurate Standard, 162 — - Coils, Construction of, 145 — Coils Heating with Strong Ctur- rent. 192 Coils, German Silver, 160 Coils, Iron, 162 Coils, Platinoid, 161 Coils, PlatiuumSilver Alloy ,160 Coils, Materials used in, 159 Coils, Modes of Winding, 163 Colls, Temperature Varuttion of, 153 Increase of, by Self-induction. 4SS7 of Current Generator, Conden- ser Method ol Measuring, 342 of Danieirs Cell, 211 of Grove's Cell, 218 of Insulators. Diminution of^ with Increase of Temperik ture, 271 — of Insulators, ll<<asuring, 275 of InMuIators, Table of, S71 ^— of Insulator to Sparking, 811, 370, noU, 358 Law of Variation of, with Tem- perature, 152 Measuring, by Rate of Loss of Charge, 8i4, 348 Measuring, Containing E.M.F.. 469 Maasiuring, during Pasasfe of Strong Current, 187 510 PRACTIOAL RLBCTBICITT. Beeistaaoe, Measaring Higrh, 277 If etal haTing Least Ciiaace of, with Tempentuxe, 160 Paranel, 179 of Ottlranometer and Shunt Combined,. 178 — — of Metalt for Giren Length and Diameter, or for Given Length and Weight. Ifi6 ^^ of Metala per Cubic Centimetre, and per Cubic Inch, 158 of Platinoid, 161 per Cubic Centimetre, and per Cubic Inch Compared, 34B •^— Proportional to Batio of Poten- tial Difference to Current, 130 ihould be High in Potential Difference GalTonometera, 137 — — should be Low in Current Gal- vanometers, 136 Unit of, British Association, 141 Unit of. Legal, 140 Unit of. Siemens', 142 — - Variation of, with Length, 143 Variation of. with Material, 146 — Variation of. with Sectional Area, 146 — Variation of. with Temperature, 147, 152 Variation of Sensibili^ of Gal- vanometer with, 416 Variation of Sensibility of Voltmeter with, 407, 418 Voltmeters with Outside, 421 Besults of Experiments Corrected bj Drawing Corves, 34 of Experiments. Graphioallj Recording, 30 •^— o( Experiments. Value of Curves in Graphical]/ Be* cording, 38 Interpolation of, from Curve, 84 Retardation, Definition of, 831 Reversing Current without Alter- ing its Value, 47 Revolving Doubler, Ivicholson's, 366 Ring, Guard, 89 Ross CeU, 210 Rotatoiy Eleotropboms, 861 Rough Experiments, Candles to use in the place of Standard Candles for, 452 Rubbing Two Bodies together. Quantity of Electricity Produced by, 118 — Two Bodies together to Pro- duce Electrification, Ob> ject of, 115 <— — ^i^o Bodies together, Equality of Charges Obtained bj, 115 Bumford's Photometer, 40 Bymer Jones' Constant Total Ca» rent Shunts, 2S9 8 Scale, CATUBATION, ^ of Liquid, Definition of. 4U Safety Axrangement with Com- mutator Ammeter. 4Si Connection between Motion of Image on Plane, and Angnlar Deflection of Mir- ror, 107 for Tangent Qalvanomefeer, 38 Mode of Making Tangeot, 30 Scales, Accuracy of Reecungs with Degree and Tangent Com- pared, 40 Screen. Msgnetio, Thick Iron Bo^ 101 Screw, Micrometer, Deseiiption of, tioe«,24 Sealing HermeticaUy, Definition of, note, 90 — up One End of Cable when under Test, 268 Secondary Batteries, Small Internal Beoistance of, 206, 261 •^ — Batteries. Use of, in Eleetrio Lighting. 261 Sectional Am, Variation of Besist- anoe with, 146 Self-Indnetion, 174, 427 Induction, Small, in Caidow's Voltmeter, 427 Sensibilities of C<nnmutator Am- meter, Batio of, in Parallel and in Series, 431 —^ of Commutator Voltmeter. Batio of, in Parallel and hi Series, 488 SensibHitv, Adjustment for, in jiagnifyinff Spring Am- meters and Voltmeters, 389 — ^ of Galvanometer, Variation of, 21,48,229 —^ of Ghilvanometer, Variation of. with Length of Wire used in Winding, 418 —^ of Galvanometer, Variation of, with Besiataince, 416 Tangent Galvanometer Al- tered 1^ Bemoving Needle from Plane of CoH, 52 Tangent Galvanometer Al- tered by Vsryin^ Number of Windings or Diameter of BobUn, 48 Voltmeters, Variation of, with Change of BesistanoOa 407,418 of of IKDBX. 011 Bemslbility of Wheatstone's Bridge, Condittons affeotmg,171,406 of 'Wheatatone'B Bridge, Mode of Inoreuing, 168 — ^of Weight Eleotrometer, In- creaedng, br Using Aaxilip ai7 High Poteutial, 91 — — > Shrmting Qalranometer to Dimioiah, 2S9 "— Testing Amxneten for Ferxna- sent Alteration of, 407 Two Degrees of, in Commatator A'limeter and Voltmeter, 427 Series, E. M. F. of Cells in, S41 G«lls in, Fi«nue of, 239 Cella in. Symbolical Repre- sentation of, 240 Wires Joined in, 140 Several "Onirente Meeting at a Point, Law Connecting, 464 Shell-lac, Beetstance of, 271 ^lac Specific Inductire Capa> ci& of, 810 -lac vamisb. Coating Insn- lating Stems with, 267 — > -lao Vamiah, Preparation of, nottf, 238 Shielded, Dead-Beat, Direct-Read- ing Qalvonomet^rs, Advan- tages of, 78 Shielding Galvanometers from £z- traiieona Magnetic Btstarb* anoe. 87, 73, 108, 380 Short-Cirenited, Defluition of, 217 Shunts, 80, 177, 183, 253 Shant Box, Construction of, 181 Shunts, Constant Total Current. 257 Shunt and QalvanometerjCombuied Resistance of, 178 • Increase of Total Current pro- duced by Use of, 188, 253 — -> Measuring Besistanoee of Bat- teries by means of, 226 Multiplying Power of, 178 — Multiplying Power of, when Used in Measuring Dis- charge, 948 Shunts, Use of, with Differential Galvanometer, 183 Shunt, Use of, with Wheat8tone*s Bridge, 176 Shunting Battery only while Charg. ing Condenser, Arrange- ment for, 843 ^— Galvanometer to make it Less Sensitive. 229 Siemens' Electro-Dynamometer, 877 -— Electro-Dynamometer, Advan- tages of, 380 —— Electro-DynamometeTy DisadU Tsntages of , 381 Eleotro • Dynamometer, Measuring Current with, 379 Electro-Drnamometer as Stan- dard Instrument, 382 Siemens' Unit of Resistance, 148 Silver, Change of Resistance of, with Temperature, 160 —— Electric and Heat Conductivi ties of. Compared, 158 ^— Resistance of, for Given Length and Diameter, and for Given Length and Weight, 157 Resistance of, per Cubic Centi- metre, and per Cubic Inch, 154 Chloride Battery of De la Rue and Hugo MCUler, 314 Voltameter, Description of, noUf 11, 895 Voltameter, Precautions in Using, not«, 11 -— Voltameter, Use in Calibrating Ammeters, 395—400 Voltameter Used by Lord Rayleigb, U, 895 Voltameter, Weight of Silver Deposited on Plate of, per Second, by One Ampere, 11 Similarly Charged Bodies ; Keason they Fly from One An- other, 340 Simple Substitution Method of Comparing Resistances, 138 Voltaic Element, 209 Sine, Definition of, nets, 88 Galvanometer, 62 — — Galvanometer, Foster's SimpU- flcatiou of, 61 —— Law, Conditions under which it is True, 61 Law, How Conditions of, are Fulfilled in Sine Galvano- meter, 62 Method, Calibrating Galvano- meter by, 64 — - Metbodof Calibrating Galvano- meter with Constant Cur- rent, 67 Method of Calibrating Higher Parts of Scale, 65 3cale, Method of Making, 68 S7i'iibg Resistance Boxes, 186 t?:iuill Current, Disadvantage of using Voltameter to Mesr sure, 20 Soft Iron Cores used in Galvano^ meters, 73 Solenoid, Definition of, not«, 387 Sparking, Resistance to, of Insib ktors, SU, nets, 858 513 PRACTICAL BLECTRICITT. SpMks between BeUs of Eleetrioal M aebinee. Length of, 870 Electric. 858 Potential Differaioe Boqtdred to Produce, between Point end Plate. 371 Potential Differonoe Beqnxred to Prodace, between Two Hetallio Balls, 870 Sphere, Capacity of, in Space, 330 Spherical Condenser, Capacity of, 838 Spirit Levels for Befleoting Galvano- meters, 285 Sprciflo Inductive Capacity* Defini- tion of, 809 Indnctive Capacity of Solids and Liquids. 310 IndactiTe Capacity, Meaanrix^r, 33i Specimens of Instructions for Ex- periments, 476 Sprincr Control Meters, 877 Control Meters, Ounyng- bame*s. 388 ^^ Control Meters, Magnifying, 886. (Sm also Magnifying Spring Ammeter and volt- meter.) Control Meters, Siemens', 377 Squared Paper, Drawing Curves on, 81 ^— Paper, Meaning of Inaocara- eies in Carves Drawn on, 83. ^P^ Selection of Suitable Units on, 81 Paper, Use of, 30 — • Paper, Using, to Find Angles from th& Tangents, 56 Paper, Using, to Find Tangents m>m their Angles, 57 Standard Air Condenser, 334 Candle, Description of, 458 Cells, 410 Daniell's Cell, 411 Daniell's Cell. E. M. F. of, 412 DanieU's Cell, Fleming's, 412 Voltmeter, 422 Static and Current Methods of Meanurinff Potential Dif- ferena<>s Compared, 125 — ■ Electric Apparatus, Neceflsary Enclosure of, in Metallic Case, 108 Statical Method of Comparing Capacities, 330 Stems, Coating Insulating, with Paraffin Wax or 8nell-la« Vamiab, 267 Storsge Cells, Smnll Internal Be- sisl^vuoe of, 261 Storage Cells, Measuring Bwrfghinf of, 206 Strength of Cnrrent, Measnzcineut of, 4 of Current, Why Measured by Chemical Proper^, 10 of Electro- Magnet, Law of, when Core is Slightly Mag- netised. 382 of Poles of Single Needle of Galvanometer, Calibration Unaffected by, 23 Striking Distance, D«ifinition of, «iot«,371 Strong Current, Measuring Besist- ance during Pa»>sage of, 187 Subdividing Potential Difference into Known Fractions, 278 Submarine Gable, OH«city of, 809 Substitation, Simple, Method of Com^arixur Besistaaoes, 138 Solphnr Dioxide, Specific Inductive Capacity of, 310 SpecificluductiveCapaeityof ,310 Sulphuric Add, DUute, EflTeot of Electrolysis of, 15 Add Voltameter, ComitraetioB of, 18 Acid Voltameter, DeecriptioB of. 6. Acid voltameter, Obiection to Ordinary Form of, 18 AeidVoltameter, Volume of Gas produced in, per Second, or one Ampere, 12 Add voltameter. Weight of Gaa produced in, per Second, by one Ampere, 22 Super-aatiuation of Liquid, Deflni* tion of, noU, 411 Snrfsee Leakage, 266 *.ii..i. a«. M^w of ^270 of Condactor. £lectridty at Best Besides Onlv on. 118 Suspension, Fibre, used m Thouk- son's Marine Qalvnnome- ter,6C Suspensions, Pivot and Fibre, C<mw pared, 60 Symbolical Bepresentation of Bat- teries, 173, 240 rpABLE of Electrie and Heat -^ Condnotifities, 150 of Besistances of Insulators, 271 of Besistances for a Given Length and Diameter, or for a Given Xength and Weight, 157 INDEX. 513 Table of Seslstances of Metals par Cabic Centimetre, and per Cabic Incb. 154 ^— of Specific Inductive Capaci- ties, 310 of TemperatnTe Variation of Besistance, 160 sbowinff Poteutial, Density, ondQuMntity of Electricity on Condnctor in Different Conditions, 123 sbowiDg Variation of External Besistanoe, Current, and Potential Difference at Battery Terminals, 205 Tangent of Augle of Deflection Proi)Orti«»nal to Otirrent in Tangent GtalTauometer, 43 — Definition of, no'«, 37 and Degree Scides, Accuracy of Beadings Compared, 40 CMvanometer, 36 — Galvanometer, Alteration of Sensibility of, bv Altering Position of Needle, 51 Galvanometer, Adjustment of Coil of, 46 - — — Ghilvanometer, Best Deflection to Use with, 41 Galvanometer, Calibration of Galvanometer by Direct Compjirison with, 58 — — Galvanometer, Conditions to be FulKUed in, 36 Galvanomet<>r, Controlled Only by the Earth's Magnetism, Values in Amperes of De- flections of, 55 — — Galvanometer, Fulfilment of Conditions for TftUo'Cut Law in, 43 Galvanometer, Proportions of Channel in Bobbin of .when Tangent Law is Most Ac- curately Fulfilled, 51 — Galvanometer, Scale for, S9 Galvanomtrter, Simple Form of, 27 -^— Law, How Conditions of, are Fulfilled in Tangent Gal- vanometers, 43 Law, When True, 41 Scale, Mode of Making. 38 Tangents, Finding Angles from, by means of Squared Paper, 56 TelegrH>h Insulators, 274 Insalators. Testing during Manufacture, 275 Tel^rraphy, Besistance Boxes used in Duplex, 187 Telephone, Description of the Bell, 336 H H Temperature, Change of Besistance with, Beeults of Mutthies- sen's Experiments on, 160 — — Curve, Coobng Correction of observed Kise of, 196 Diminution of Besistance of Insulators with Increase of, 271 Equation connecting Variatiou of Besistance of Metals with, 153 ^— Law of Variation of Besistance with, 152 Measurement of. Compared with Measurement of Po. tential, 85 Variation of E, M. P. of Lati- mer Clark's Cell, 411 Variation of Resisiau.e with, 147 T^'-tting Ammeters, 394 Ammeters for Accuracy of Gi-aduation, 395 Ammeters for Error on Re- versing the Current, 402 ". — Ammeters for Error Produced by External Magnetic Dis- turbance, 403 — Ammeters for the Pcrnf>Bnent Alteration of Seniitil.ty, 407 — — Ammeters for Residual Mag- uetism, 4G0 ^— Cables, Sew ling up One End while. 268 Insulators during Manufac- ture, 275 Voltmeters, 407 Voltmeters for Accuracy of Gniduation, 4'J8 Voltmeters for Heating Error, 415 Testing. ( See also Comparing, Mea- suring.) Thompson's, Prof. Silvanus P , Rule for Best Dimensi^ I'l uf Channel of Bobbin « f Tan- gent Galvanometer, 51 Thomsons, Sir William, Arrange- ment for luL-reasing a Potential Difference in Known Ratio, 354 — Astatic Galvanometer, 283 — — Astatic Gralvanometer, Modi- fied Form of, S^ Electrometers, 93 Electrometer, Edelmann's Form of, 130 Large Current Galvanometer. 53 — — Leyden Jar, 315 — - Marine Galvanometer, 103 514 PRACTICAL BLECTRIOITT. ThomMB't, BIr WillJ«m, Murine Galnmometer, Fibre 8a»> jpenaion used in, 60 — ^Marme G«lTftnometer, Shields ing, from Ma^etic Di» tnrbeaoe, 108 Befleotinf QmlTiuiometer, 98S Bepleniflher, 964 Time Bise of Temperatoxe due to Paanm of Current, 195 Tin, Chanice of Beeistanoe of, with Tempeimture, 160 -— Eleotrio end Heat CondnctiTi- tiea of, Ck>nipaied, ISO «—— Beeiatanoe of , for Otirea Length and Diameter, and for Given Length andWeight, 157 — — Besistanoe of, per CnUo Cen- timetre, and per Cubic Inch, 154 TTKIFOBM Controlling Field, ^ Proportional'OalTanometer with. 72 Magnetic FieId,Deflnltionof , 86 Magnetlo Field, Motion of Magnet Produoed in, 800 Potential on Condnotor, 86 Unit of Capacity, 807. of Current, 11 of Density, 117 of Potential DiiTerenoe, 89, 141 of Power, 448 of Quantity, 880 of Besistance, B.A., 141 of Beeiatanoe, Britiah Aaeocia- tion, 141 of Beeiatanoe, Legal, 140 of BeeiaUooe, Siem^na', 148 of Beeiatanoe, B. A. and l^egal. Compared, 148. Unite, Seleeoon of. Suitable on Squared Paper, 82 'VTALUBS in Amperea of Defleo- ^ tiona of Tangent Oalvano- meter ContzoUed On^ by Earth'a Magnetiam, 55 Variable Besietance in Voltmeters caused by Self>Liduotion with Alternating Potential DiiTerenoes, 427 Variation of Capacity of Condenser with Area of, and Distance between, its Coatings, 808 ——of External Beoistance, Cur- rent, and Potential Dif- at nAK204 Variation of Magnetio Effect of Bobbin with Current and Besistanoe, 418 of Besistanoe with Length, 143 of Besistanoe with Mat erial, 146 •^— of Bedstanoe with Sectional Area, 146 -^of Beeiatanoe with Tempera- ture, 147 —-of Beeistance with Temi>er:V' tnre. Law of, 158 — — of Sensibility of any GalTaoo- meter by Althing Disr- meter of wire, 22 of Sensibili^ of any Oalvano- meter with Length of Wire used in Winding, 418 — — ' of Sensibility of any Galvano- meter by fehnntuig, 229 "— of SensiUlil^L^ Galvanometer with Its Besistanoe, 416 of Sensibility of Tangent Gal- Tanometer, 48 of Sensibility of Voltmeter with Chanee of its Besistanoe, 407,418 '—— Produced in Total Current by Shunting Portion of dircuit,258 — — with Temperature of E. M. F. of Daniell's CeU. 211 with Temperature of E. M. F. of Ladmer Clark*s Cell, 41 1 Varley's Accumulating Influence Machine, 367 Varnish, Coating Insulating Stems with SheU-hu), 867 How to make Insulating, aote, 268 Varnishing Shade of Ordinary Gold- Le«f Electroscope 97 Varying Potential Dttferenoe in Known Batio, 878. 354 Vibration, Definition of Periodic Time of, 291 Voltaic Element, 209 Voltameter cannot Measure Alter- nating Current, 196 Copper, Description of, 6, U. (Sat also Copper Volta- meter.) — — ' Hoffmann's. 15 Silver, Used by LordBayleigh, 11,805 ——Sulphuric Add, ConstruotMB of, 18 Sulphuric Add, Descriptionof, • ^— > Sulphuric Acid, V<dume of Gaa produced m, per «*^*«»<^| by One Ampere, 12 IND£Z. 515 Voltameter, Sulphnrio Add, WetglLt of Qns produced in, per S«ooud« by Ooa Ampere, Zino. {8e» Zinc Voltameter.) Voltameter!, Objections to usnal U ode of Const meting, 18 -•— and QalvanometerB, Relative AdTHnt««e8 of, 20 ^— Direotion of Cnrrent ia Acid, Copper, and Zinc, 15 Diaadvantaffe of, 20 Independence of Gaa Generated and of Metal Deposited of Shape, Sise, and Distance Aptut of Plates, 10 Precautions in Utdxi^t no(«, 11 — - Silver, not*, 11 •^— Silver, Use of* in Calibrating Ammeters, 80S-40J Weights of Metals Deposited on Plates of, per Second, by One Ampors, 11 Wliy Only Used ti Measuring Large Currents, 20 Volt, The, 86 Practical Definition of the, Ul Provisional Definition of the, 80 Voltmeters, 128, S76 Voltmeter, Cardew's Latest Form of,iffi Cardew's, Advantages of. 426 Cardew's, Arranized for Moosar- ing Large Potential Dif- ference'*, 425 Cardew's. Diameter of Wire Used in, 423 Tardew's, Disadvtntage of, 427 Cardew's, Length of Wire Used in Latest Form of, 423 Cardeov's. No Heating Knor in, 426 Cardew's, Self-Indnetion Small in, 427 Commiitator, 427 Commutator, Calibrating, 483 — - Conynghame's, 388 — — Ouiynghame'B,Advantagea and Disadvantages of, S85 — — Cnnynghame's, Graduation of, Electro-Msgnetio Control, 888 •—Electro-Magnetic Control, Cxompton and Kapp's, 802 _ Electro-Magnetic Control, Patezson and Cooper's, 883 — Electxo-Msgnetio Control, Ad- vantage and Disadvantage of, 804 Oravilgr Control, 801 Voltmeter Gravity Control, Ad- vantages of, 391 Oravity Control, Disadvantages of, 394 Magnifying Spring, 386 Mugnifying Sprmg, Adjust- ment for Sensibility in, 380 Magnifying Spring, Advantages of, aoo — ^Msgnifying Spring:, Best Law of Gauge of W ire for Coils of, 421 ^— Msgnifying Spring, Diaadvau- taoe of, 391 ^—Magnifying S^ag, Indication of Direction of Current in. 880 — — Permanent Magnet, 00 Permanent Magnet, Advantages of. 78 — Permanent; Magnet, Defect of, 876 — Permanent Magnet, Diroct- Beading, 76 Spring Control, 877 Standard, 4. '2 with Magnifying Gearing, 3S6 Best Material for Coils of, 420 Best Material for Co.Ij of Ex. temal RedBtance for, 422 — Best Law of Gauge of Wiro for. 4fiL Calibrating by Comparison with Standard Cell. 410 Calibrating, by FoggundorflTs Method, 413 -— ' Calibrating, with Known Cur> rent aod Sesiatance, 408 Errors in, 407 with Eztcgrnal Besistaiice, 421 — Waste of Energy in, with High Eztemal Besibtaucr, 42*J Testing, 407 testing, for Aoonnusy ol G rodu- ation.406 Testing, for Heating Error, 4l5 Variation of Sensibility 3f, nvlth Change of its Besiatauce, 407708 Variation of Sensibility of, with External Besistanoe. 42L Variation of Sensibility of, with Speed of Alternation of Potential DUfereno, 427 Volilme of Gas Prodaced per Second in Sulphuric Acid Voltameter by One Am- pere, 18 Voss* Accumulating Infiuenoe Ma* ohine, 367 Valoanised Indiarabber, Hooper's, ~ of, 271 516 PRAOnCAL ELECTBICITT. W TKTASSE of EiDorgj in Voltmoten ^^ with High External Be- sistauoe,42& ~^of Ener^ in Friotional Eleo- trieal ICachinM, 852 Water, Current of, in Pipe Compared with Eleotiio Current, 3, 80 Difference between Preasore of. Flowing in a Pipe, and Electrio Potential, 81 Equivalent, Definition of, 198 Jacket, Use of, 198 Watt, Definition of the, 448 Work done in One Minate and One Second, when One, ia Developed, 443 Wattaneter, Conatmotion of, 444 Errors in, 445 Wax, Coating Insulating St«>ms with Paxafiln, 887. (Sm also Paraffin.) Weighing, Meaaozing Potential Dif- ference by, 88 Weight Electrometer, 88 Sleotrometer, Increasing Sen- sibilitT oc, by usiug Aux- ilianr High PotentiiQ, 91 ——of Gas rrodnced per Second, in Sulphuric Add Volta- meter, by One Ampere, 12 Wheatatone's Bridge or Balance, 166 Bridge, Arms of, 172 —^ BridgB, Qest Azxangement of Battory and Qalvanometer with, 171. 467 Bridge, Best Besiataace for Arms of, 171 — Bridge. Commercial Form of, 178 Bridge, Conditions Affecting iSensibility of, 171 Bridge QalTanometer, Best &e- aistance for, 172, 466 Bridge Oalvanometer, Current through, 465 Bridge Giuvanometer, Meaning of Ddflection of, 176 > Bridge, Mode of Increaaing Sensibmty of .168 Bridge, Key for, 174 '— - Bric^, Superiority of, over Differential QalTanometer, 171 Bridge, Use of Shnnt with, 176 Wiedemann and Franc's TsUe oC Heat ConduetiTitiea oi Metals, 159 Wimahurst Influence Machine, 367 — > Influence Machine, Attaching Leyden Jars to CoUectora of. 370 — 'Influence Machine, CoUectin^ Combs of, 369 •^—Influence Machine, Work done by, 371 Winding Besistanoe Coils, Mode of. 163 Windings, Variation of Sensibility of a GalTunometer with Number of, 49 Wire and Liquid Besistanoes, Com- parison of, 194 Best Gauge of, for Differential GalTauometer. 436 — - Best Gau^ of, for GalTano- meterm SimpleCircait,483 Beat Gauge of, for Galvano- meter of Wheatatone's Bridge, 172, 466 Wires Joined in Parallel. 136 Joined in Seriea, 140 Work done by Current Generator, 202 '— done by Wimshurst Influence Machine. 371 done in Electric Circuit, 199 ——done per Minute, and per Second, when One Watt ia Developed, 44S yAMBONI'S Construction of Dry ^ Pile, 373 Zero Instrument, Definition of, 380 Zinc Amalgam, 218 How to Amalgamate, 218 — ~- Besistanoe of, for Given Length and Diameter, and for Given Length and Weight, 187 — Besistanoe of, per CuUo Centi. metre, and per Cubic Inch, 154 — Temperatare Variation of Be- sistance of. 160 — > Voltameter, Direction of Cur- rent in, 15 Voltameter. Weight of Zinc Deposited on Plate of, per Second, by one Ampere, 11 raiarSD bt cabssxx * ooxpavt, uvini), la bsllb SAVTAev, Loanom, ■.o. 5.893. Selections from Casseil # Company's PublUations, illuBtratetr, JTiiu-^rt, antr ti^tc jfolttm^s. Abbeys and Churches of England and Wales, The : Descriptive, Historical, Pictorial. Two Series, ais. each. A Blot of Ink. Translated from the French by Q and Paul Franckb. Across Thibet. By Gabribl Bonvalot. Two Vols. 3M. Adventure, The World of. Fully Illustrated. In Three Vols, gs. each. Africa and its Explorers, The Story of. By Dr. Robert Brown, F.L.S. Illustrated. Vol. I., 78. 6d. Arabian Nights Entertainmente, Cassell's Pictorial. los. 6d. Architectural Drawing. By R. PhrnA Spiers. Illustrated, zos. 6d. Art, The Magazine of. Yearly Vol. With la Photogravures, Etching's &c, and about 400 Illustrations. x6s. Artistic Anatomy. By Prof. M. Duval. Cheap Edition. 3s. 6d. Astronomy, The Dawn of. By Norman t.ociCVBR, F.R.S., F.R.A.S. Illustrated, royal 8vo, ais. Atlas, The Universal. A New and Complete General Atlas of the World, with 117 Pages of Maps, handsomely produced in Colours, and a Complete Index to over zoo,ooo Names. Cloth, 30s. net ; or halt. morocco, 35s. net. Bashkirtseff, Marie, The Journal of. Cheap Edition. 7s. 6d. BashldrtseiF. Marie, The Lettera of. 7s. 6d. Beach of Falea&, The, and The Bottle Imp. By R. L. Stevenson. Illustrated, ss Beetles, Buttenlies, Moths, and Other Insects. With za Coloured Plates from " Der Insekten-Sammler." 38. 6d. Biographical Dictionary, CaBseH's New. 7s. 6d. Birds' Nests, Eggs, and Egg- Collecting. By R. Kbarton. Illus- trated with 16 Coloured Plates. 5s. Black America. By W. Laird Clowes. 6s. Blue Pa^lions, The. By Q, Author of "Drad Man's Rock," &c 68. Bob Lrovell's Career. A Story of American Railway Life. By Edward S. El^lis. 5s. Breechloader, The, and How to Use It. By W. W. Greener, as. British Sallads. With 275 Original Illustrations. In Two Vols. X5S. British Battles on Land and Sea. By Jambs Grant. With about 600 Illustrations. Three Vols., 4to, £z 7a.; Library Edition^ £j xos. British Battles, Recent. Illustrated. 4to, 9s. ; Library Edition, los. Bunyan's Pilgrim's Promss and The Holy War, CasBell's Illus- trated Edition of. With aoo Original Illustrations. Cloth, 165. Butterflies and Moths, European. With 6z Coloured Plates. 3ss. Canaries and Cage-Birds, The Illustrated Book of. With 56 Fac- simile Coloured Plates, 35s. Half-morocco, £a 5s. Carnation Manual, The. Edited and Issued by the National Carnation and Picotee Society (Southern Section). 3s. 6d. Cassell's Family Magaaine. Yearly Vol. Illustrated. 9s. Cathedrals, Abbeys, and Churches of England and V^ales. Descriptive, Historical, Pictorial. Pofmlar Edition, 1'<9to Vols. a5s. Celebrities of the Century. Cheap Edition, los. 6d. Cities of the World. Four Vols. Illustrated. 7s. 6d. each. Civil Service, Guide to Employment in the. 3s. 6d. Climate and Health Resorts. By Dr. Burnsv Vbo. 7s. 6d. Clinical Manuala for Practitioners and Students of Medicine. A List of Volumes forwarded post free on application to the Publishers. Colonist's Medical Handbook, The. By E. A. Bahton,M.R.C.S. a8.6d. Colour. By Prof. A. H. Church. With Coloured Plates. 3a. 6d. 5 o* 8-9« SehcHons from Cassell % Company s Pvhlicaiieiu, Columbus, The Career of. By Charlss Elton, Q.C ios. 6d. Commercial Botany of the Nineteenth Century, as. 6d. Conning Tower, In a. By H. O. Arnold-Forstbs, M.P. is. Cookery, A Year'a. By Phyllis Brownb. AVw and En'arggd Ediii&H, 38. 6d. Cookery, CasaelPs Dictionary of. Containing about Nine Tboosand Recipes. 78. 6d. ; Roxburgh, los. fid. Cookery, CasaeH's Shilling. 384 pages^ limp cloth, is. Cookery, VegeUrian. By A. G. Pavne. is. 6d. Cooking by Gas, The Art of. By Marie J. Sugg. Illustrated. 38 6d. Countries of the World, The. By Robert Brown, M.A., Ph.D., &c. Complete in Six Vols., with about 750 Illustrations. 410, 7s. 6d. each. Cromwell, Oliver. By J. Allansom Picton, M.P. 58. Cyclopaedia, Casaell's Concise. Brought down to the latest date. With about 600 Illustrations. Chte^ Edition* 78. 6d. Cyclopaedia, Casaell's Miniature. Containing 30,000 subjects, as. 6d. Dickens, Character Sketches from. First, Second, and Third Series. With Six Original Drawings in each by F. Barnard. 2:8. each. Dick Whittington, A Modem. By James Payn. Two Vols., aia. Disraeli, Benjamin, Personal Reminiscences of. By K. Lake. 38. 6d. Dog, Illustrated Book of the. By Vero Shaw, B.A. With 38 Cclouied Plates. Cloth bevelled, 358. ; half-m<»occo, 458. Dog, The. By Idstone. Illustrated, as. 6d. Domestic Dictionary, The. Illustrated. Cloth, 78. 6d. Dor£ Bible, The. With aoo Full-page inostntions by Gustavb DoRt. Cloth gilt, gilt edges, 258. Dor^ Gallery, The. With 950 Illustrations by DoRlL 410, 4^8. Dora's Dante*8 Inferno. Illustrated by Gustave DorjL With Intro- duction by A. J. Butler. Cloth gilt or buckram. 78. 6d. Dora's Milton's Paradise Lost. Illustrated by DorA. 4to, azs. Dr. DumAny'a Wife. A Novel. By Maurus J^kai. 7s. 6d. Earth, Our, and its Story. By Dr. Robert Brown, F.L.S. With Coloured Plates and numerous Wood Engravings. Three Vols. as. each. Fdinbureh, Old and New. With 600 Illustrations. Three Vols. os. each. Egypt: Descriptive, Historical, and Picturesque. By Prof. G. Ebkrs. With 800 Original Engravings. Pp^uiar Edititm. In Two Vols. 42s. Electricity in the Service of Man. Illustrated. 98. Electricity, Age of. Bv Park Benjamin, Ph.D. 78. 6d. Electricity, Practical. By Prof. W. E. Ayrton. 78. 6d. Encyclopaedic Dictionary, The. In Fourteen Divisional Vols., Z08.6d. each ; or Seven Vols., half-morocco, axs. each ; half-russia, 258. En^and, Cassell's Illustrated History of. With 2,000 Illustrations. *. Ten Vols., 4to, 98. each. Rroistd Edition, Vols. I to V, 9s. each. Engliah Dictionary. Cassell's. Giving definitions of more than 100,000 Words and Phrases. Cloth, 78. 6d. Cheah EdiHon. 38. 6d. English History, The Dictionary of. Ckgap Edition. los. 6d. English Literature, Dictionary of. By W. Davenport Adams. Chfap Edition, 78. 6d. ; Roxburgh, zos. 6d. English Literature, Library of. By Prof. Henry Morlbt. Vol. I.— Shorter English Poems. 7s. 6d. Vol. II.— Illustrations op English Religion. 7s. 6d. Vol. III.— English Plays. 7s. 6d. Vol. IV.— Shorter Works in English Prose. 78. 6d. Vol. v.— Sketches of I^nger Works in English Verse and Prose. 78. 6d. StleeHans from Cassttt # Compan/s Publications. £nslish Literature, Motley's Pint Sketch of. Reviud Ediiiom, 7«.6d. English Literature* The Story of. By Anna Buckland. 3a. 6d. English Writers. By Prof. Henry Morlsy. Vols. I. to VIII. 5s. each. JBsop's Fables. Illustrated by Ernest Grisbt. Cloth, 3s. 6d. Etiquette of Good Society, xs. ; cloth, xa. 6d. Fairway Island. By Horace Hutch i)«sok. With 4 Full-page Pl.ttes. 58. Faith Doctor, The. A Novel. By Dr. Edward Egglsston. 7s. 6 J. Family Physician, The.- By Eminent Physicians and Surgeons New and Rtviud Edition. Cloth, axs. *, Roxburgh, 358. Father Stafford. A Novel. By Anthony Hope. 6a. Field Naturalist's Handbook, The. By the Rev. J. G. Wood and Rev. Theodore Wood. 5s. Piguier's Popular Scientific Works. With Several Hundred Illustra- tions in each. Newly Revised and Corrected. 38. fid. each. The Human Race. | Mammalia. I Ocean World. The Insect World. Reptiles and Birds. World before the Deluge. The Vegetable World. Flora's Feast. A Masque of Flowers. Penned and Pictured by Walter Crane. With 40 Pages in Colours. 5s. Football, The Rugby Union Game. Edited by Rey. F. Marshall. Illustrated. 7s. 6a. Four Years in Parliament with Hard Labour. By C W. Radclipfb CooKB. Third Edition, is. Prance as It Is. By AndrA Lebon and Paul Pelbt. With Three Maps. Crown 8vo, cloth, 78. 6d. Garden Flowers, Familiar. By Shirley Hibbbrd. With Coloured Plates by F. E. Hulme, F.L.S. Complete in Five Series, xas. 6d.each. Gardening, Cassell's Popular. Illustrated. Four Vols. 5B. each. George Saxon, The Reputation of. By Morlev Roberts. 58. Gilbert, Elizabeth, and her Work for the Blind. By Frances Martin, as. 6d. Gleanings from Popular Authors. Two Vols. With Original Illus* trations. 4to, os. each. Two Vols, in One, 158. Gulliver's Travels. With 88 Engravings by Morten. Ckoa^ Edition, Cloth, 38. 6d. ; cloth gilt, 5s. 