Mr Graham oil the absorption of Vapours by Liquids. 8S9 



column the composition of the solutions is given, of which 

 700 grains were always employed. When the proportion ox 

 salt in the solution is not expressed, it is to be understood that 

 the solution was a saturated one at the temperature of the at- 

 mosphere, which varied during the experiment from 55° to 42°. 

 In the second column the increase or loss of weight under- 

 gone by the different solutions, after being inclosed for six days, 

 is expressed ; and in the third column the additional increase 

 or loss of weight, after farther confinement for fourteen days. 

 In a fourth column the boiling points of the solutions are sub- 

 joined, for a purpose which shall be presently explained. 



224° 



214.5 



213 : 



214 



214 



221 



221 



230.5 



216.5 



212 



From the experiments of this table, and from other experi- 

 ments yet to be detailed, it is evident that not only the solu- 

 tions of salts, which are deliquescent, but that the solutions of 

 salts which are persistent in the air, and even of efflorescent 

 salts, are capable of absorbing vapour in an atmosphere nearly 

 saturated with it. Some of the results are curious. It ap- 

 pears from the table that a saturated solution of common salt, 

 which contains less than a third of its weight of a saline sub- 

 stance, which is not deliquescent, absorbs vapour much more 

 powerfully than a solution of the deliquescent carbonate of po- 

 tash in twice its weight of water. In fact, it appears that 

 all saline solutions just as readily inhale as exhale vapour, ac- 

 cording to the state of the atmosphere in which they exist. It is 

 this proposition in all its generality which I wish to establish. 

 As the powers to absorb and to emit vapour appear to be 



