Electromotive Forces in the Voltaie Cell. 277 
affinity may have in changing the numbers, it will have the 
same effect on all. 
It is easy to write down the hypothetical series in bromine 
and iodine in the same way:— 
Calculated Volta Series in Bromine and Iodine. 
Metal. In Bromine. In Iodine. 
Potassium ......... oo 3°50 
Zine... 1:74 we 
aie 2 5 55. o's 3°40 87 
RORVE. no x~ ence 1:10 “60 
LT “89 23 
Hydrogen ......... “40 —13 
All this supposes the metals to be perfectly clean, and not 
covered with a film of foreign gas like oxygen. On the 
hypothesis that the metal has been taken recently out of air, 
and that the film of oxygen with which it is covered has to 
be torn from the metal, though it was not actually combined 
with it, the Volta series in chlorine or hydrochloric acid would 
be quite different, and more like this. 
Hypothetical Volta Series of Air-coated Metals in Chlorine 
or HCl 
SS Aes ee eee 1°8 
1 ra2 7 gals Senne Sane i=? 
Wr Gite cs ces des sancwastes cos Tt 
Copper. .s-.- Solace Shei 9 
TSE Grd Se A eae 85 
Unfortunately I can get no data for the heat of chlorination 
of nickel ; but assuming it not very different from iron, the 
above series gives copper and nickel in the right order, as 
observed by Mr. Brown, whereas the other one did not. I 
have no experiments with which to compare the numbers. 
Calculated Volta Series of Clean Metals in Sulphur or 
Sulphuretted Hydrogen. 
Heat of Sulphuri- 
Metal. zation per gramme Volts. 
equivalent. 
Potassium ......... 91276 1:95 
ATT See Se ee 41880 ‘87 
Pras. 2: sens: anaes 35506 76 
Mead st. Se eee 19112 “41 
Copper. 4 se..5 18266 39 
ERVOR . scxfoee dee faves 11048 34 
Hydrogen ......... 5482 12 
