274 A CENTUEY OF SCIENCE 



fying minerals. The German school, led by Werner, 

 classified minerals according to their external characters 

 while the French school, following Haiiy, put the empha- 

 sis on the "true composition." Cleaveland remarks that 

 "the German school seems to be most distinguished by a 

 technical and minutely descriptive language; and the 

 French, by the use of accurate and scientific principles in 

 the classification or arrangement of minerals." He, 

 himself, tried to combine in a measure the two methods, 

 basing the fundamental divisions upon the chemical com- 

 position and using the accurate description of the physi- 

 cal properties to distinguish similar species and varieties 

 from each other. 



Cleaveland 's mineralogy was followed nearly twenty 

 years later by the Treatise on Mineralogy by Charles 

 U. Shepard already mentioned. The first part of this 

 book was published in 1832. This contained chiefly an 

 account of the natural history classification of minerals 

 according to the general plan adopted by Mohs, the 

 Austrian mineralogist. The second part of the book, 

 which appeared in 1835, gave the description of indi- 

 vidual species, the arrangement here being an alpha- 

 betical one throughout. Subsequent editions appeared 

 in 1844, 1852 and 1857. 



James Dwight Dana was graduated from Yale College 

 in 1833 at the age of twenty. Four years later (1837) he 

 published ' ' The System of Mineralogy, ' ' a volume of 580 

 pages. The appearance of this book was an event of 

 surpassing importance in the development of the science. 

 The book, of course, depended largely upon the previous 

 works of Haiiy, Mohs, Naumann and other European 

 mineralogists, but was in no sense merely a compilation 

 from them. Dana, particularly in his discussion of 

 mathematical crystallography, showed much original 

 thought. He also proved his originality by proposing 

 and using an elaborate system of classification patterned 

 after those already in use in the sciences of botany and 

 zoology. He later became convinced of the undesira- 

 bility of this method of classification and abandoned it 

 entirely in the fourth edition of the System, published in 

 1854, substituting for it the chemical classification which, 

 in its essential features, is in general use to-day. The 



