468 



INDEX TO VOLUME II. 



OIL BATH. 

 Oil bath heated by Bunsen burners, 



144 ; raising and lowering tem- 

 perature of, 145. 

 Oil and electric light, penetrating 



power of, 207 ; refrangibllity of, 



compared, 207. 

 Ordinary air furnace compared with 



electric furnace, 226. 

 O'Shaughnessy, W., laid in 1839 



first underwater cable at Calcutta, 



26. 

 Outer sheathing, failing of, 112, 113 ; 



importance of, 112. 

 Overground telegraph wires, 20. 

 Overland and submarine routes to 



India considered, 194, 195. 

 Oxidation of metal plates in relation 



to thickness, 130. 

 Oxy-hydrogen blast, used for fusion 



of metals, 221. 



PACINOTTI'S ring used in Gramme 

 machine, 215. 



Parabolic section of tube telegraph 

 post strongest, 133. 



Paris electrical exhibition, dynamo- 

 electric railway at, 249. 



Paying out apparatus, simple as 

 possible, 89. 



Paying-out cables, considerations in, 

 186 ; depth of water, retarding 

 strain in dependent on, 186 ; if 

 heavy, hazardous in deep water, 

 106 ; machinery for, Newall and 

 Co.'s, 28 ; method of. 89 ; slack 

 in, 186. 



Paying-out and picking-up, by same 

 machine, 115 ; machine used on 

 board the Dix Decembre. 115 ; 

 (machinery, compound, 140 ; 

 should not be separated by ship's 

 length, 114). 



Pearsall, Steinheil, reference to, 43 ; 

 on twisted wire rope, 43. 



Penetrating power, of different 



PLATINUM. 



illuminants, 192 ; of early applica- 

 tions of electric light, 207 ; of 

 electric and oil light, 207; of 

 light, depends on intensity and 

 quantity, 207. 



Persian Gulf cable, success of, 110, 

 111. 



Phonograph and brain action, 

 analogy between, consideration 

 of, 197. 



Phonograph, record and reproduction 

 of sounds by, 197. 



Phonographic record analogous to 

 memory, 197. 



Physiological research, microphone 

 applicable to, 197. 



Picking-up, cable from bow, 115 ; 

 faulty cables, speedily, importance 

 of, 115 ; and paying-out ma- 

 chinery, compound, 140. 



Pipe-clay, variation of resistance 

 with temperature, 166. 



Pixii, in 1833, constructed dynamo- 

 electric machine, 199. 



Plants, appearance and growth of 

 improved by electric light, 227, 

 231 ; light, continuous, favourable 

 to, 230. 235, 257 ; uninjured by 

 carbonic acid or nitrogenous com- 

 pounds (if any existed) from 

 electric light, 230. 



Plasticity of gutta-percha favourable 

 for covering conductor, 99. 



Platinum, applicability of for high 

 temperature thermometers, 164 ; 

 (ball pyrometer, description of, 

 149 ; method of employing, 149 ; 

 principle of, 149 ; used for deter- 

 mining temperature of blast, 149 ; 

 used for testing formula of elec- 

 trical resistance at high tempera- 

 tures, 150") ; coefficient of increase 

 of resistance of , 143 ; conductivity 

 of, affected by inter-mixture of 

 metals, 143 ; (experiments on elec- 

 trical resistance of, description of, 

 144 ; diagrams and tables of, 145 ; 



