131 



The fifth proposition is proved by the fact that in the following 

 solutions of salts of potassa, all of the same strength (namely 1 salt 

 to 10 water), a difference in the amount of evaporation in each will 

 be observed to have taken place, and it must be borne in mind that 

 in solutions so weak we cannot expect that difference to be very 

 great. 



The reason for employing weak solutions was the necessity for 

 having all of the same strength, one in ten being the extent, to which 

 the least soluble salt submitted to examination, namely, the sulphate 



of potassa, will, at a low temperature, dissolve. 



grains. 



Acetate of potassa lost in 35 hours 145 



Bicarbonate of potassa lost in 35 hours . . . 131 



Carbonate of potassa lost in 35 hours . . . 115 



Ferro-cyanate of potassa lost in 35 hours . . 110 



Hydrochlorate of potassa lost in 35 hours . . 98 



Nitrate of potassa lost in 35 hours . . . . 117 



Sulphate of potassa lost in 35 hours .... 132 



Tartrate of potassa lost in 35 hours . . . . 151 



The above solutions were next made all of one specific gravity, 

 namely 1'060, temp. 62 Fahr., instead of being all of one strength, 



and the following is the result : 



grains. 



Acetate of potassa lost in 16 1 hours .... 46 

 Bicarbonate of potassa lost in 16| hours ... 45 

 Carbonate of potassa lost in 16| hours ... 35 

 Ferro-cyanate of potassa lost in 16J hours . .41 

 Hydrochlorate of potassa lost in 16| hours . . 32 

 Nitrate of potassa lost in 16| hours .... 39 

 Sulphate of potassa lost in 1 6 J hours .... 42 

 Tartrate of potassa lost in 16^ hours .... 43 



The sixth proposition is rendered probable by the following ex- 

 periment, in which solutions are employed of acetic, nitric, sulphuric, 

 and hydrochloric acids, combined respectively with potassa, soda, 

 and ammonia, in the proportion of 100 grains of the salt to 1000 

 grains of water. After the expiration of 10 hours and 20 minutes, 

 the solution of the three acetates lost respectively, for the potassa 

 salt 35 grs., for the soda salt 35 grs., and for the ammonia salt 

 28 grs. In the solutions of the three nitrates, the loss was re- 

 spectively 24, 25 and 25. In the solutions of the three sulphates, 



