Shepard* s Treatise on Mineralogy. 639 



sisting of Descriptions of the Species, and Tables illustrative 

 of their Natural and Chemical Affinities. In two volumes 

 8vo, 631 pages; with 500 woodcuts. New Haven, United 

 States, 1835. 



The principal feature of this work is, that it takes a dic- 

 tionary form, and enumerates the mineral species in an alpha- 

 betical order. This is certainly a useful plan, because it does 

 not tie the collector or examiner to any particular or individual 

 arrangement, which ought to be left open till the science shall 

 have assumed a more fixed character. 



Mr. Shepard has availed himself, in a praiseworthy man- 

 ner,— of the various treatises by Phillips, Leonhard, Mohs, 

 Hauy, Berzelius, Cleveland and Parker, Beudant, Breit- 

 haupt, Brand, Allan, Hartmann, &c.,and gives as much from 

 each as is suitable to his purpose. The crystallographical 

 works of Brooke, &c, have supplied him with his illustration 

 of the forms of the varieties of crystals. 



It is to be regretted, that the synonymes, and derivations 

 and authorities thereof, are not given, as well as the nomen- 

 clature Mr. Shepard prefers. Many persons, accustomed to 

 look for minerals under certain designations, may not like the 

 arrangement. We give one instance : Triplite, -prismatic 

 parachrose baryte, is designated by Leonhard, phosphorsaures 

 mangan, and correspondingly by Phillips, phosphate of man- 

 ganese. This is a complete revolution : but if the synonymes 

 had been given, there could have been no objection to it. 



The first volume is preceded by a natural-historical (na- 

 tural-history?) arrangement, in which are introduced a new 

 order, Picrosmine (from the Greek, pikros, bitter, and os?ne, 

 odour), in allusion to the smell, when moistened ; and a new 

 genus, Lusine-ore (from luo, to dissolve), for those species 

 which seem to result from the decomposition of others. This 

 latter is a disputed idea; we think justly so. There is no 

 reason whatever to suppose that such things occur. By de- 

 composition the component parts of one mineral may go to 

 form another, when in combination with other agents : but 

 will this justify Mr. Shepard's classification ? At the brick- 

 pits near Cambridge, selenite may be seen in the act of form- 

 ing from the decomposition of iron pyrites ; yet it could be 

 hardly said, that the former is the decomposed variety of the 

 other. Dr. Johnston's remark, in p. 565. of this volume, 

 respecting the Lerna3 N a uncinata, applies equally here. Neither 

 this nor that is " transformed agayne nature." 



The second volume concludes with a chemical arrange- 

 ment, suggested by Mr. J. D. Dana, upon the plan of that of 

 Berzelius, Mohs having furnished the model of the natural 



