416 



Dr. Gr. Grore on a New Method and 



Volts, 

 1*20 



Fig. 16. 

 Curve of KCl+NaCl at 13° C. 



Grains i r'v ,l ? ,( ? i, ? :) ? 5 T ,< ? ,1 'i : ''P < pyT*t~ 



1st. Each of the curves is strikingly unlike in general 

 form each of those of the constituent salts of the compound, 

 and the form is not in either case an average of that of the 

 two ; each of them also shows a great reduction of electro- 

 motive force due to the chemical union of the two constituents. 

 2nd. In each case an increase of strength of solution is 

 attended by an increase of electromotive force. 3rd. The 

 two curves are each characteristic of the individual substances. 

 ' The amounts of voltaic energy of the dissolved salts separately 

 before chemical union were :— KC1 = 699,803, NaCl = 207,589, 

 and KT = 16,361; and after the union those of the compounds 

 were :— KCl4-KI = 7,571,andKCl + NaCl = 5,959 (see "Re- 

 lative Amounts of Available Voltaic Energy of Aqueous Solu- 



tions," Proc. Birm. Phil. Soc. vii. part i.). 



13. Curves of Isomeric Electrolytes. 

 I have already shown (see Phil. Mag. October 1889, 

 •p. 289, " On the Molecular Constitution of Isomeric (Solu- 

 tions ") that aqueous isomeric electrolytes yield different 

 amounts of voltaic energy with a zinc-platinum couple. In 

 the present case I employed the same pair of mixed aqueous 

 solutions as were used in that research, viz. an unstable one 

 " A " having a composition represented by the formula 

 Na 2 S0 4 + 2ELN"0 3 , and yielding an average voltaic energy 

 = 77,446; and its stable isomer "B" represented by 

 2NaN0 8 + H s S04, and yielding 32,722. The degrees of 

 strength of the series of solutions employed were those which 

 were the most easily worked, and were from *01 to *1 grain of 

 the mixture in 155 grains of water. The constituent solutions 

 of u A," previous to being mixed, contained *01 grain of 

 substance per cubic centimetre ; if they were stronger than 

 this there was risk of the liquid undergoing a chemical change 

 during the mixing. 



