224 



PROCEEDINGS OF THE AMERICAN ACADEMY 



tenth of a cubic centimeter of strong sulphuric acid to about one hun- 

 dred and fifty cubic centimeters of distilled water, gave the liquid used 

 in the last two observations. 



III. The electromotive force of the alloys of lead and tin, with 

 total resistance of 22,G08 ohms, the constant being the same, and the 

 liquid as stated above. 



IV. The electromotive force of the alloys of copper and zinc, with 

 a total resistance of 2,380 ohms, and the same constant of galvanometer 

 and the same liquid as in the preceding determination. 



It would seem to follow, from the last table at least, that in acid 

 solutions the electromotive force of alloys is determined by the pro- 

 portional part of that metal which is most readily attacked by the 

 acid. 



