eRe Y See 
XXII. On the Determination of Chemical Affinity in terms of 
Electromotive Force-—Part IX. By C. R. AupER WRIGHT, 
D.Sc. (Lond.), F.RS., Lecturer on Chemistry and Physics, 
and C. THompson, #.C.S., Demonstrator of Chemistry, in 
St. Mary’s Hospital Medical School*. 
[Concluded from p. 124.] 
D. Voltaic and Thermovoltaic Constants of Metals immersed 
in Solutions of their Acetates. 
I. Copper. 
194. A NUMBER of cells were set up with amalgamated- 
zine and electro-copper plates immersed in solu- 
tions of their respective acetates, the constant molecular 
strength being -25 M(C,H;0,), H,O*. ‘The following values 
were obtained :— 
Wire ss gy er OA 
WEI ge a ee LOWS 
pegeraselr Ore Se ae VOT 
Enobable error: “..).« ».. "0029 
Julius Thomsen’s thermochemical data lead to the values 
Zn, O, 2C,H,0,a9.= 100710, and Cu, O, 2 C.H,O,aq. =50340; 
whence Hy=1-'111, corresponding with 50370 gramme- 
degrees. Hence H—Ey=—-020 for electro-copper in contact 
with copper-acetate solution of strength °25 Cu(C,H30.), 
100 H,0. 
Il. Lead. 
195. Two series of cells set up with electro-lead opposed to 
amalgamated zinc and electro copper respectively, with acetate 
solutions uniformly of strength ‘25 M(C,H;0,), 100 H,0, 
gave the following results ; the differences observed between 
the values obtained for different cells set up in the same way 
being notably greater than with most of the other com- 
binations examined :— 
Zinc-Lead. Lead-Copper. 
——SE—_ O———— eS —— 
Mia ximiimny Ss cae auenaen ‘616 503 
Miniiniam sees 587 ‘471 
PAVING O) ore temas Beach 608 "485 
Probable error ......... +:0048 +:0044 
* The acetate solutions employed were prepared by dissolving the 
freshly-precipitated, well-wasked carbonates of the metals in boiling 
dilute acetic acid somewhat stronger than that required, filtering alter 
cooling, and diluting to the proper extent, 
