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of brevity, only state the result of one or two experiments in proof 

 of each. 



The first proposition is proved by the fact that a solution of hydro- 

 chlorate of soda in the proportion of 480 grains to four measured 

 ounces of water, when exposed under the conditions already stated to 

 spontaneous evaporation, lost only 33 grains in weight after twelve 

 hours' exposure, while four ounces by measure of water lost 53 grains, 

 and after twelve hours' further exposure lost only 109 grains, while 

 the water lost 1 74 grains ; that is, the water, as compared with the 

 solution, lost weight in the ratio nearly of 5 to 3. 



The second proposition is proved by the fact that a solution of 

 240 grains of hydrochlorate of soda in four ounces by measure of 

 water lost in twelve hours 73 grains by evaporation, while four ounces 

 by measure of pure water lost 81 grains, this is in a proportion 

 of only about 8 of the latter to 7 of the former ; whereas, when double 

 the quantity or 480 grains of salt were dissolved, the pure water, 

 as compared with the solution, lost in the proportion of 5 to 3. 



The third proposition is proved by the fact that a solution of 480 

 grains of nitrate of potassa in 4 ounces or 1920 grains of water lost 

 in twelve hours 95 grains ; while a solution of the same strength of 

 hydrochlorate of soda lost only 70 grains ; and again, a solution of 

 loaf-sugar, in which 480 grains were dissolved in 1 920 grains of water, 

 lost in 20 hours 1 75 grains, while a like solution of hydrochlorate of 

 soda lost only 117 grains. 



The fourth proposition is proved by the fact that 480 grains of 

 gum-arabic dissolved in 1920 of water had a specific gravity of 1 *072, 

 while a solution of hydrochlorate of soda of like strength had a spe- 

 cific gravity of 1*149 ; after 1 1| hours, the former had lost by eva- 

 poration 71 grains, while the latter had lost only 50 grains. Here, 

 therefore, the solution of the lighter specific gravity was less retarded 

 in its evaporation than the heavier solution. In contrast with this 

 fact, a solution of hydrochlorate of ammonia of 480 grains to 1920 

 grains of water, having a specific gravity of only 1*060, lost by evapo- 

 ration, in 8 hours and 44 minutes, 1 7 grains, while a like solution of 

 hydrochlorate of soda lost 24 grains. Here, then, the solution of 

 lighter specific gravity was more retarded in its evaporation than the 

 heavier solution. The cdnclusion is decisive that specific gravity has 

 no necessary connexion with the phenomena. 



