1880.] The?' mo-Electric Behaviour of Aqueous Solutions, Sfc. 249 



Difference of amount 

 of Deflection. 



18. Nitrate of strontium 



19. Cyanide of potassium (3 grs.) ^ 



20. Sulphite of sodium (12 grs.) ' 25 



21. Nitrate of ammonium * 



22. Microcosmic salt (60 grs.) ver ^ sli % U 



23. Sulphate of sodium ^ 



24. Selenate of sodium 2 ^ 



25. Nitrate of sodium ' 25 



26. Nitrate of barium ' 25 



27. Boracic acid 



1225 



28. Ammonia alum (60 grs.) Qr 



29. Selenic acid (12 minims) ^ 



30. Selenic acid (24 minims) " 



31. Ammonia alum (120 grs.). . 



32. Sulphuric acid (1 in 80) 



33. Sulphuric acid (1 in 40) 



34. Sulphuric acid (1 in 20) 



4-0 



The total differences 12*25 and 4*0 in this series agree as nearly as 

 could be expected with the maximum deflections 110 and 4"25 in the 

 previous series. 



Remarks. — The strength of the solution was found to have but 

 little influence upon the direction of the current. Increase of strength 

 of solution increased the amount of deflection in solutions of cyanide 

 of potassium, sulphite of sodium, and selenic acid, and to a less 

 extent in those of formiate of sodium, formic acid, microcosmic salt, 

 and ammonia alum. 



With the solutions of sulphuric acid, those of intermediate strength 

 (1 in 40) gave a greater deflection at 180° F. than either a stronger or 

 weaker one. No other' instance occurred in which a solution gave a 

 greater deflection at the temperature of 180° F. than a stronger solution 

 of the same substance. 



On comparing the results now found with platinum with those 

 previously obtained with mercury, it will be seen that the two sets 

 are very similar. The conclusions, therefore, which have already 

 been drawn from the former apply largely to the latter, and need not 

 be repeated. The chief conclusion, viz., that the currents previously ob- 

 tained with mercury were really due to heat and not to minute amounts 

 of chemical action, is largely confirmed by the present research. The 

 chemical relations of mercury being considerably different from those 

 of platinum in special cases, if the currents were due to chemical 

 action, the two sets of results would have been widely divergent in 

 their orders. 



