254 Natural History. [Chap. IIL 



SECTION VI. 



HYDROLOGY. 



The natural history of Waters holds so important 

 a place among the objects of human knowledge, 

 that it has, in almost every age, attracted the at- 

 tention of those who loved to study nature : but 

 it is only within the century under review that 

 any thing on this subject deserving the name of 

 science, or a correct acquaintance with principles, 

 covdd be said to exist. The accessions to Hy- 

 drology in modern times have been very great. 

 The improvements in Chemistry, in Mineralogy, 

 and in many other sciences, have contributed much 

 to enlarge our knowledge in this department of 

 philosophy. 



The comparative qualities of common -waters^ 

 whether falling in rain^ or found in springs^ wells^ 

 or lakes^ were observed and ascertained, during 

 the eighteenth century, with a degree of intel- 

 ligence and accuracy never before known. For 

 the experiments and inquiries which have led to 

 our knowledge on this subject, we are chiefly in- 

 debted to Bergman, Scheele, Carradori, Hassen- 

 fratz, and Guyton-Morveau. 



The taste, specific gravity, and other properties 

 of sea water^ were also examined with new ac- 

 curac3% and with new results. For many en- 

 lightened experiments in tliis branch of hydro- 

 logy, we owe much to Sparrnian, Bergman, lord 

 Mulgrave, M. Pages, Mr. Biadh^ Dr. Watson, and 

 Mr. Kirwan. 



