WATER 111 



vironment, other no less important physical 

 properties exist. Such especially are those 

 characteristics of liquid water which in no 

 small measure determine the nature of the 

 resulting physico-chemical systems when other 

 substances, whether soluble or insoluble, crys- 

 talline or colloidal, are brought into contact 

 with it ; I mean the solvent power, the dielec- 

 tric constant, together with the related ioniz- 

 ing power, and the surface tension. 



A 



WATER AS A SOLVENT 



As a solvent there is literally nothing to 

 compare with water. In truth its qualifi- 

 cations are on this point so unique and ob- 

 vious that nobody seems to have taken the 

 trouble to gather together the evidence, and, 

 accordingly, beyond the bare assertion, a brief 

 statement of the facts is not easy. 1 In the 

 first place the solubility in water of acids, 

 bases, and salts, the most familiar classes of 

 inorganic substances, is almost universal. 



1 Nearly the whole science of chemistry has been built 

 around water and aqueous solutions. A reference to any text- 

 book will at once reveal the truth of this statement. At first 

 sight such a condition appears to be a matter of chance, but, 

 as one becomes more familiar with the true character of the 

 science, realization of a rational justification for the historical 

 fact steadily grows. 



