TABLE 262 (continued). 253 



COMPOSITION AND ELECTROMOTIVE FORCE OF VOLTAIC CELLS. 



- * E. M. F. hitherto used at Bureau of Standards. See p. 251. The temperature formula is Et= 20 0.0000406 

 (t 20) 0.00000095 (t 2o) 2 -}- o.oooooooi (t 20) 3 . The value given is that adopted by the Chicago International 

 Electrical Congress in 1893. The temperature formula is E t = E 1B o.ooi 19 (t 15) 0.000007 (*~ J 5)* 



t F. Streiutz gives the following value of the temperature variation at different stages of charge : 



dt 



E. M. F. 1.9223 1.9828 2.0031 2.0084 2.0105 2.0779 2.2070 



dE/dtXio 140 228 335 285 255 130 73 



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

 Per cent H,SO 4 64.5 52.2 35.3 21.4 5.* 

 E.M.F., oC 2.37 2.25 2.10 2.00 1.89 



SMITHSONIAN TABLES. 



