S14 Dr. Andrews's Report on the Heat of Combination. 



They were all chemically pure. The density of each solution com- 

 pared with water at the same temperature was also determined. 



The first solution of nitrate of potash contained for every 100 

 parts of water 25*29 parts of the salt. The thermal values of the 

 thermometer with large reservoir described in the paper already 

 referred to, in terms of this solution and of water, were found in 

 alternate experiments to be — 



Solution I. Water. 



5044 4095 



5047 4107 



5050 4116 



Mean. 



5047 



4106 



The temperature of the air during these experiments varied only 

 from 18°C. to 18°-5 C. 



The second and third solutions contained respectively 12*645 and 

 6*322 parts of nitrate of potash for 100 parts water. Air from 18°*5 

 to 18°*9. 



Solution II. 

 4600 

 4620 

 4605 

 4610 



Solution III. 

 4393 

 4387 

 4385 



Water. 

 4118 

 4105 

 4108 



Mean. 



4610 



4387 



4110 



From these data the specific heats of these solutions at the tempe- 

 ratures at which the experiments were performed, as compared with 

 water at the same temperatures, may be easily computed. I have 

 given them in the following table, as also the specific gravities of the 

 liquids. 



I. II. Ill, 



Specific heat 0*8135 0-8915 0*9369 



Specific gravity 1*1368 1*0728 1*0382 



The solutions of nitrate of soda contained 42*49, 21*245 and 10*622 

 parts respectively of nitrate of soda for 100 parts of water. The 

 temperature of the air ranged from 17°*5 to 18°*8 during these ex- 

 periments. 



Solution I. Water. Solution II. Water. Solution III. Water. 



5261 4107 4775 4116 4499 4116 



5234 5117 4782 4098 4498 4098 



5247 4119 4787 4100 4488 4100 



Mean. 



5247 4114 



Specific heat . . 

 Specific gravity 



4781 4105 

 I. II. 



0*7838 0*8585 



1*2272 1*1256 



4495 



4105 



III. 

 0*9131 

 1*0652 



Of chloride of sodium two solutions were examined, the first con- 

 taining 29*215, the !?econd 14*607 chloride of sodium for 100 water. 

 The air was nearly steady between 17°*9 and 18°. 



