PHYSICAL CHARACTERS OF MIXTURES AND SOLUTIONS. 
34D 
To heat 5 grms. of this solution from 5 0, 5 to 23 0, 8 requires 83T7 units. 
To heat the water alone „ „ „ 83T7 „ 
KN 0 3 one molecule, or 4-76 per cent, 
H 2 0 112-3 molecules, or 95-24 „ 
Specific heat of this solution, calculated from Thomson’s Tables, -943. 
In the formation of 5 grms. of this solution are absorbed, at a temperature of 
5-7, 20 - 57 units. 
19-7, 19-16 „ 
Difference 1*41 
To heat 5 grms. of the solution from 5 0, 7 to 19 0, 7 requires 66-01 units. 
To heat the water alone „ „ „ 66-66 „ 
The data for calculating the heat absorbed in this and in the preceding solution are 
taken from Graham, Otto’s ‘ Chemie,’ vol. i. part 2, by IT. Kqpp. 
Solution of Potassium Hydrate. 
Iv H O one molecule, or 9-4 per cent. 
EL, 0 thirty molecules, or 90 - 6 „ 
Specific heat of solution, according to Thomson, -876. 
In the formation of 5 grms. of solution are evolved, at a temperature of 
4-0, 54-05 units. 
31-6, 61-75 „ 
Difference 7 "70 „ 
To raise 5 grms. of solution from 4° to 31 0, 6 requires 120-885 units. 
To raise the water alone „ „ „ 125-030 „ 
Every one of the preceding eight mixtures conforms with proposition 2, and most of 
them also fairly enough with proposition 1, the only signal exception being the mixture of 
ethylic alcohol and bisulphide of carbon. A very close correspondence can only be 
expected where all the necessary data have been estimated with accuracy and at the 
required intervals of temperature. Some amount of error is, however, unavoidable ; and 
that mixture which is least affected by such small errors, will serve best to bring out 
the real connexion existing between the various properties. Now none of the eight 
sets of mixtures considered equals the mixtures of ethylic alcohol and water in this 
respect, and we find accordingly that these most nearly conform to the law. These 
mixtures have therefore been chosen, not only as the best illustrations of the law, but 
also as a guide in tracing similar relations between the corresponding properties of 
other mixtures and solutions, relations which, being in those cases more liable to be 
masked by small experimental errors, might otherwise have been overlooked. 
