290 Dr. GL Gore on the Molecular 



of Chemistry,' by L. Meyer, translated by Bedson and 

 Williams, 1888, pp. 470, 485.) ^ 



Experiment 1. — I have examined this instance by means of 

 the " voltaic-balance " method with zinc and platinum couples 

 (see Roy. Soc. Proc. vol. xlv. pp. 265, 268), and have obtained 

 the following results. Distilled water was used in making all 

 the solutions. 



TABLE I. Voltaic 



energy. 

 " A." Na 2 S0 4 4-2HN0 3 gave between 73,313 and 81,579 at 18° C, Average 77,446 

 "B." 2NaN0 3 +H 2 S0 4 „ „ 31,000 „ 34,444 „ „ 32,722 



The solutions of each ingredient of these two mixtures were 

 considerably diluted previous to mixing. 



The numbers obtained with the mixture " A " are much 

 more variable than those obtained with the one " B," and it 

 will facilitate the clear understanding of the subsequent parts 

 of this research if I here state that the mixture tt A " is an 

 unstable one, and liable to change in molecular constitution 

 and amount of energy both during its formation and after- 

 wards. 



It is worthy of notice that notwithstanding the average 

 voltaic energy of sulphuric acid in water is about 3*9 millions, 

 and that of nitric acid in water is only about 3*2 millions (see 

 Table II.), the mixture "A" containing the latter acid has 

 about 2'3 times the amount of such energy of the one " B " 

 containing sulphuric acid : this is probably explained by the 

 changes of energy which occur during mixing. 



The amounts of enero-v show that the distribution of acids 

 and base in the two isomeric liquids " A " and " B *' were 

 very different. It is evident that if one of the mixtures con- 

 sists of u two thirds of the soda combined with the nitric acid, 

 and one third with the sulphuric acid," the other liquid must 

 have a very different molecular arrangement ; and that " the 

 final division of the base between the two acids " is not 

 always " the same whether the soda were originally present 

 as sulphate or nitrate." The amounts of voltaic energy ? how- 

 ever, appear consistent with the statement that " when nitric 

 acid and sodium sulphate react in equivalent quantities in 

 aqueous solution, heat is absorbed ; but when sulphuric acid 

 and sodium nitrate react, under similar circumstances, heat is 

 evolved/' The mode of preparing each liquid will he 

 described. 



In each of these two solutions the following compounds 

 may possibly be present : — H 2 S0 4 — HN0 3 — Na 2 S0 4 — NaN0 3 

 — 2HN0 3 , H 2 S0 4 — Na 2 S0 4 , H 2 S0 4 — 2NaN0 3 , H 2 S0 4 — 



