DILUTION OF CONCENTRATED SOLUTIONS. 351 



(2) That when the solutions become more dilute they, at the same time, become 

 more complex ; 



(3) That those thermal changes occur in strong aqueous solutions, which suggest 

 that the solute is dissolved, not in water, but in some definite hydrate of the solute, 

 in general containing a large number of molecules of water. 



In special cases, however, such as that of acetic acid, the water molecules may be 

 few in number, while with nitric and hydrobromic acids the solvent becomes pure 

 water. 



(4) That calcium chloride does not show the effect in so marked a degree, probably 

 because it is impossible to work with solutions of the same relative strength. 



Full facilities for the execution of this research have been most kindly afforded by 

 Prof. CALLENDAR. The author wishes to thank him, and to express his appreciation 

 of Prof. CALLENDAR'S advice and encouragement throughout the work. 



VOL. CCXV. A. 3 A 



