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only natural road to Mineralogy 1 I think not. T have frequently used 

 the best Ameiican text-books on Mineralogy in my classes, and in my 

 own researches, and I have arrived at my conclusions, notwithstand- 

 ing the ability they displaj^ in setting forth the present methods of that 

 study. Requesting thei'efore a continuance of your very kind atten- 

 tion whilst I explain to yon the working of that system, I hope to suc- 

 ceed in persuading you of the necessity of making in it certain inno- 

 vations. 



A complete course, even of elementary Mineralogy, includes three 

 divisions — Theoretical JMineralogy, Descriptive Mineialogy and Detei- 

 minative Mineralogy. Those among my I'eaders who have devoted an 

 occasional leisure hour to this study are familiar with these expres- 

 sions and know exactly the object of each of those departments of the 

 science. Authors un Mineralogy do not usually treat of all the three 

 divisions. When they do, they generally write a separate work on 

 each. Thus the great American mineralogist and geologist, James D. 

 Dana, has published "A Complete System of ^Mineralogy," including 

 all the principles of the science and esjiecially the mathematical intrica- 

 cies of Crystallography. In another work under the same title he gi^-es 

 a. description of all the species known. But he left to his confrere, Mr. 

 Brush, the honor of publishing a Determinative Mineralogy. Now it 

 is evident that a text-book intended to convey to the student an ade- 

 quate idea of the science, not of course of all its details, but of its entire 

 system and general features, must embrace the elements of all the three 

 divisions. Give the student nothing more than Theoretical Mineralogy 

 and unless he is a born mathematician, how canyon expect him to solve 

 the mysteries of the famous six systems, letter the planes resulting from 

 the fiftieth successive tiuncation of a crystal, without ever hoping 

 to have a tangible proof that all those fantastic figures have not 

 been systematically devised to puzzle his poor brain, and give him a 

 higher course of pure solid (Toometiy in di.sguise. So much for the 

 atti'activeness of the study. But, leaving that altogether aside, place 

 in the hands of the student a long list of species more oi less connected ; 

 require him to remember the crystalline form, possible? structure, capri- 

 cious cleavage, variable colours, doubtful lustre of every mineral, ^ive 

 him no credit if he does not give its hardness and its specific gravity to- 



