Table 262 {continued). 253 



COMPOSITION AND ELECTROMOTIVE FORCE OF VOLTAIC CELLS. 



Name of cell. 



Negative 

 pole. 



Positive pole. 



E. M. F. 

 in volts. 



(b) Single Fluid Cells. 



Leclanche . . . 



Chaperon . . . 

 Edison-Lelande . 

 Chloride of silver 

 Law 



Dry cell (Gassner) 

 Poggendorff . . 



J. Regnault . . 

 Volta couple . 



Amal. zinc 



(< <i 



<i « 



Zinc • • 



Amal. zinc 



Zinc 



Solution of sal-ammo- 

 niac 



Solution of caustic 

 potash 



23 % solution of sal- ) 

 ammoniac . . . . ) 



ipt.^ZnO, ipt.NHiCl,] 



3 pts. plaster of paris, 1 

 2pts. ZnCU.and water [ 



to make a paste . . J 



Solution of chromate / 

 of potash .... J 



12 parts KoCroO; -|- ) 

 25 parts H2SO4 -j- > 

 ICO parts HoO . . ) 



I part H2SO4 + 



12 parts H2O -J- V 

 I part CaS04 . . ) 



H2O 



f Carbon. Depolari- 1 

 zer : manganese I 

 peroxide with f 

 [ powdered carbon J 

 I Copper. Depolar- \ 

 \ izer : CuO ... J 

 ({ 



( Silver. Depolari 

 ( zer : silver chl'ride 

 Carbon , 



Cadmium 

 Copper . 



146 



0.98 

 0.70 

 1.02 

 1-37 



1-3 



1.08 

 2.01 



0-34 

 o.q8 



(0) Standard Cells. 



Weston normal 



Clark standard 



jCadmi'ml 

 \ am'lgamj 



( Zinc I 

 ( am'lgaml 



Saturated solution of 

 CdS04 



Saturated solution of 

 ZnS04 



Mercury. "| 



Depolarizer: paste I 

 of Hg2S04 and ( 

 CdS04 ... .J 



Mercury. \ 



Depolarizer; paste 1 

 of Hg2S04 and [ 

 ZnSOi ... .J 



1.0191 

 at 20° C 



1-434* 

 at 15° C 



(d) Secondary Cells. 



Lead accumulator 



Regnier (i) . . . 

 (2). . . 



Main . 

 Edison 



Lead 



Copper . 



Amal. zinc 

 Amal. zinc 



Iron . . 



( H2SO4 solution of ) 

 I density i.i . . . ( 



CUSO4+H2SO4 . . 



ZnS04 solution . . . 

 H2SO4 density ab't i.i 



KOH 20 % solution . 



PbOo 



" in H2SO4 

 A nickel oxide 



- * E. M. F. hitherto used at Bureau of Standards. See p. 251. The temperature formula is E, = E^o — 0.0000406 

 (t — 20) — o.oooooog; (t— 20)2 + 0,00000001 (t— 20)^. The value given is that adopted by the Chicago International 

 Electrical Congress in 1893. The temperature formula is E, = E,b — 0.00119 (t~'5) — 0.000007 (1—15)2. 



t F. Streinti gives the following value of the temperature variation — - at different stages of charge : 



dt 



Dolezalek gives the following relation between E. M. F. and acid concentration : 

 Per cent H2SO4 64.5 52.2 35.3 21.4 5.J 

 E.M.F., o°C 2.37 2.25 2.IQ 2.00 X.89 



Smithsonian Tables. 



