VOL. LXXVIII.] 



PHILOSOPHICAL TKANSACTIONS. 



471 



Muriatic acid. 



Proportion 



of water to 



acid. 



10: 1 

 5.1 : 1 

 3.05 : 1 



Freezing 



point by 



experiment. 



Freezing 



point by 



calculation. 



25 

 18| 

 9t 



Salt of tartar. 



25 

 18J 



Spirit of salt being a very weak acid, its increase of ratio was not perceptible 

 within the limits to which he was confined. 



This table is constructed as the foregoing; 

 and the specific gravity of the marine acid was 

 1.163. 



Salt of tartar, such as is usually sold in the 

 shops, was the vegetable alkali employed. It did 

 not readily deliquesce, and consequently was not 

 very caustic : the cold it produced with snow 

 was — 12°. 



Here the greatest difference between the cal- 

 culation and experiment is something more than 

 14-°, in sinking the freezing point from 224° to 

 5° ; but in the higher freezing points of the table 

 it is less, as well as in the lower. Perhaps this 

 irregularity in the experiments is in part to be 

 ascribed to an impurity in the salt of tartar ; a 

 turbid appearance, and at length a deposition 

 took place in all these solutions, but principally 

 in the stronger, occasioned probably by tartar of vitriol, with which that salt is 

 so frequently mixed. 



The mineral alkali tried, which was the crystallized soda of the shops, showed 

 no increase of ratio ; but the scale of its operation was too small for a proper 

 judgment to be formed. 



This salt would not remain suspended in much 

 greater proportion in the cooled water. He con- 

 sidered the solutions as decreasing in their freez- 

 ing point by an equal ratio : possibly, if the salt 

 of tartar had been crystallized, and perfectly sa- 

 turated with fixed air, it would also have acted in 

 the manner of a neutral salt, and produced no 

 increase upon the ratio. 



Dr. B.'s volatile alkali, being the sal volatilis 

 salis ammoniaci, was tried only in 2 proportions. 

 Here also there is no appearance of an increase 

 of ratio, but rather the contrary. 



