Jantjaet 13, 1911] 



SCIENCE 



67 



microscope, makes it very difficult to measure 

 them accurately and to determine their exact 

 form. As the study of artificially produced 

 minerals would be greatly facilitated by hav- 

 ing an approximately complete collection in 

 one place, the author expresses the wish that 

 specimens of such minerals produced in various 

 countries might be sent to the Societe Miner- 

 alogique de Prance, in Paris; these, added to 

 the large number of such minerals now in the 

 College de France, etc., would make an excep- 

 tionally complete collection. An atlas of 

 colored plates figuring the most important of 

 them might then be issued by the French 

 society, and this would serve to supply the lack 

 of such material in many collections (pp. 27, 

 28). 



The aims of mineral synthesis are then pre- 

 sented at some length (pp. 28-124). The light 

 thus thrown upon the question of the natural 

 formation of minerals is noted in the case of 

 metalliferous deposits (pp. 30-33), dolomites 

 (pp. 33-37), contact minerals (pp. 37-40), the 

 formation of the diamond (pp. 43, 44), etc. 

 This is followed by sections treating of the 

 physical and chemical conditions influencing 

 the form of crystallization assumed by various 

 minerals and the order of their production, 

 and also of their systematic classification, as 

 explained or furthered by the results attained 

 in artificial reproduction (pp. 49-119). It 

 would be impossible, within the limits of this 

 article, to do more than note the convincing 

 demonstration of the great service rendered by 

 the synthetic method in the solution of many 

 difficult problems. Several mineral forms have 

 been produced in this way in a purer state 

 than that in which they naturally occur; in 

 some instances forms not yet discovered have 

 been produced, thus serving to fill up gaps in 

 the different classes. In other cases where it 

 is difficult or impossible to make an accurate 

 analysis of the natural specimens, the syn- 

 thetic products have supplied this deficiency, 

 as in the case of the chalcomenit from Argen- 

 tina which was reproduced by C. Fridel and E. 

 Sarradin in 1881 (p. 104). A very full list of 

 the spinel crystals obtained by E. Ebelman is 

 given (pp. 78-81). 



While the scientific value of these artifi- 

 cially produced minerals can scarcely be over- 

 estimated, their practical value is very slight 

 (p. 120). As the author notes, only the ruby 

 has been reproduced in a form and size that 

 renders the specimens to a great extent the 

 same as the natural stones, and yet even in 

 this case — apart from the fact that they are 

 not products of nature, but of art — a careful 

 examination reveals certain peculiarities, due 

 to the method of production, which differen- 

 tiate them from the natural rubies. 



In the special part of the work (pp. 127- 

 496) the very rich and complete material has 

 been arranged in approximately chronological 

 order, all the minerals produced by a given 

 experimenter being grouped together under his 

 name. This arrangement has its advantages, 

 although it obliges the reader to seek in diiier- 

 ent parts of the book for information regard- 

 ing any one mineral. This search is, however, 

 facilitated by very complete indexes. A sup- 

 plement (pp. 497-638) contains material omit- 

 ted for one reason or another from the main 

 work; here the arrangement is according to 

 mineralogical classification. 



Tchirwinsky has never been sympathetic 

 with Moissan at any time or in this work. 

 He has said, for excellent reasons. 



The volume contains nine excellent por- 

 traits, the list of which is here added. 



Eilnard Mitseherlioh. Professor of chemistry in 

 the Berlin University; member of the Berlin 

 Academy of Sciences; d. 1863. 



Henri Sainte-Claire Deville. Professor of 

 chemistry in the Eeole Normale and in the Sor- 

 bonne; member of the Acadgmie des Sciences; d. 

 1881. 



L. Troost. Professor of chemistry in the Sor- 

 bonne; member of the Academic des Sciences. 



F. A. Fouqug. Professor of the natural history 

 of inorganic bodies in the College de France; mem- 

 ber of the Acadfenie des Sciences. Paris. 



A. Michel LSvy. Member of the institut; gen- 

 eral inspector of mines. Paris. 



Charles Friedel. Professor of mineralogy and 

 of organic chemistry; d. 1900. Paris. 



Etienne Stanislas Meimier. Doctor of Sciences; 

 laureate of the institut. Paris. 



