318 Mt. Shepard's reply to Prof. Bel Rio. 



find the rule of preserving the species unbroken observed, since 

 they alone correspond to the classifiable objects of zoology and 

 botany'^ p. 140. 



But should the foregoing not appear an adequate justification of 

 my logic, I have only to add, that I expect those who call it in 

 question to state definitely what are the objections to any system of 

 tabular arrangements, which confining its distinctive marks to the 

 most important natural properties of minerals, conducts by the short- 

 est route to their names. 



But Prof. Del Rio proposes to try my Characteristic by putting 

 himself in the place of the young student, and commences his re- 

 marks by saying — " I suppose him at first well informed in the ter- 

 minology, and I know not how he should be, not being provided 

 with select specimens." Now I have no where said, nor ever ima- 

 gined, that a person could understand Terminology without the aid 

 of specimens adapted to that purpose. On page 4 of the Treatise, 

 under the head of method to be folloived in acquiring a knoivledge 

 of minerals, it is said, " The course to be adopted by persons aim- 

 ing at a thorough acquaintance with the inorganic kingdom, consists, 

 in the first place, in studying the properties of these bodies, and in 

 acquiring a knowledge of the terms by which they are designated. 

 This will require as a preHminary, a familiarity with a few defini- 

 tions in geometry ; and afterwards, access to a collection of mine- 

 rals arranged on purpose to illustrate the properties in question." 

 Continuing his remarks he says, " suppose the student obtains a fine 

 granular Galena, he tries its hardness and its specific gravity, and 

 he finds it by referring to the third class, to be Galena : he g6ts 

 also a cube, and finds by a second investigation, that it belongs to 

 the first class ; and when he gets also a large concretioned Galena, 

 which has three cleavages perpendicular to each other, he finds it to 

 belong to the second class, p. 202, which the author has not quoted. 

 Now, can he convince himself, although they are toto cmlo different 

 in their habit, that they are one and the same galena?" I say 

 most certainly. If he has paid the slightest attention to the chapter 

 on Classification, where a species is defined to be an assemblage of 

 identical individuals, and where it is taught that minerals not differ- 

 ing in their natural properties are identical, he will not hesitate to 

 pronounce identical the above mentioned minerals, which he finds to 

 agree precisely in hardness and specific gravity, and in whose sys- 

 tems of crystallization he discovers nothing contradictory. I con- 



