CONTENTS. XVll 



Electromotive Powers 



383. Data for voltaic cells: (a) double-fluid cells 312 



(b) single- fluid cells 313 



(c) standard cells 313 



(d) secondary cells 313 



384. Contact potential differences, solids with liquids and liquids with 



liquids in air 314 



Contact potential differences between metals in salt solutions .... 316 



Thermoelectric power of metals 317 



" '* alloys 318 



" " against platinum 319 



" " " " of platinum-rhodium alloys . 319 



*' " pressure effect 320 



Peltier and Thomson heats, pressure effects 320 



Peltier effect 321 



'* Fe-constantan, Ni-Cu, 0° to 560° C 321 



" electromotive force in millivolts 322 



The tribo-electric series 322 



Electrical Resistance 



396. Auxiliary table for computing wire resistances 322 



397. Resistivity of metals and some alloys, temperature coefficients ... 323 



398. Resistance of metals under pressure, temperature coefficients .... 326 



399. Resistance of mercury and manganin under pressure 326 



400. Conductivity and resistivity of miscellaneous alloys 327 



401. Conducting power of alloys, temperature coefficients 328 



402. Allowable carrying capacity of rubber-covered copper wires .... 329 



403. Resistivities at high and low temperatures 330 



404. Volume and surface resistivity of solid dielectrics 331 



405. Variation of resistance of glass and porcelain with temperature ... 332 



(c) Temperature coefficients for glass, porcelain and quartz . . 332 



Wire Tables 



406. Tabular comparison of wire gages S33 



407. Introduction; mass and volume resistivity of copper and aluminum . 334 



408. Temperature coefficients of copper 335 



409. Reduction to standard temperature, copper 335 



410. Annealed copper wire table, EngHsh units, B. & S. gage 336 



411. " " " " Metric units, B. & S. gage 339 



412. Hard-drawn aluminum wire table, English units, B. & S. gage . . . 342 



413. " " " " Metric units, B. & S. gage .... 343 



414. Ratio of alternating to direct current resistances for copper wire . . 344 



415. Maximum diameter of wires for high-frequency-alternating- to-direct- 



current ratio of i.oi 344 



