Force to Latent Heat 8fc. of Electrolytes. 165 



E.M.F. with Cd + Pt at 18° C. 



Volt. Volt. • 



^^^ utedsol ^ (m Z:|^ (M: | Mean E.M.F. by weight =-8746 



The more diluted solution = "8786 



p.cent. 



Increase '004 = -45 



The amounts of electromotive force in this case were 

 variable. 



The following table contains the chief results of the ex- 

 periments : — 



Table I. 



Mixture. 



Temperature. 



Mean E.M.F. 



Solution of Na 2 S0 4 + dilute H 2 S0 4 ... 



Decrease 

 „ 



)> 



>5 

 5J 



5J 

 J» 



5> 

 M 



Increase 

 )> 



>> 

 sj 



5> 

 >> 



Degrees. 

 12Fahr. 

 1-6 „ 

 •3 „ 

 8-0 „ 

 1-42C. 

 1-08 „ 



■14 „ 

 •14 „ 



•28 „ 



•54 „ 



•19 „ 



•14 „ 



•22 „ 



•04 „ 



7-14 „ 



2-38 „ 



11-00 „ 



•02 „ 



•io „ 



Increase 

 » 



Decrease 

 Increase 



3) 



•0401 



•073 



•1923 



•040 



•1228 



•0741 



*-0668 

 0359 

 •0402 

 •0445 

 •0715 

 •0345 

 •0360 

 •0787 



♦•1219 

 •0298 

 •2872 

 •2375 

 •0150 

 •004 



Solution of Tartaric Acid 4- Water ... 

 „ AmN0 3 +Water 



„ NaNO, 4- „ 



Sr2N0 3 + „ 



„ NaCl + „ 



Na 2 S0 4 + „ 



Am 2 S0 4 4- „ 



„ Na 2 C0 3 4- „ 



XN0 3 + „ 



„ AniCl 4- „ 



„ NaAcetate + ,, 



MffSO, 4- „ 



KC1 4- „ 



NaHO 4- „ 



HC1 4- „ 



H o S0 4 4- ,, 



KHO 4- „ 



H 4 N 4- , 





The various cases of absorption and evolution of heat given 

 in this table agree with those given by J. Thomsen in his 

 thermochemical researches (see P. Muir's ' Elements of 

 Thermal Chemistry,' Appendix v.). 



An inspection of the results thus obtained shows, 1st, that 

 in 19 cases out of 20 diluting an electrolyte or mixing it with 

 another increased the mean amount of electromotive force of the 

 two liquids ; and 2nd, that in 12 instances out of the 20 

 there was a lowering of temperature and an absorption of 

 heat, and in the remainder an evolution and loss of latent 

 heat, during the act of mixing. 



As in the whole of the 8 cases in which there was evolution 

 and loss of heat there was an increase of mean amount of 



* In these two cases a positive plate of zinc was used. 



