7°4 



THE POPULAR SCIENCE MONTHLY. 



a brief bibliography, and the book ends with 

 a good index. 



Precious Stones in Nature, Art, and Lit- 

 erature. By S. M. Burnham. Boston: 

 Bradlce Whidden. Pp. 4U0, with Plate. 

 Price, $3.5U. 



When beauty in any mineral that may 

 be found in Nature is accompanied by a cor- 

 responding rarity of the same, so that pos- 

 session for ornamental purposes is only pos- 

 sible to those having wealth or power, the 

 material belongs to the class of precious 

 stones. Although precious stones are not 

 indispensable to the world's progress, they 

 flatter human vanity, and have therefore a 

 not unimportant place in human affairs. 

 The large money value a precious stone rep- 

 resents compared with its volume, rendered 

 this sort of property valuable in former 

 times as an additional medium in commer- 

 cial interchange ; the perfected banking 

 methods of the present day have, however, 

 relegated precious stones to their proper 

 field — adornment and as curiosities. 



The author does not discuss the useful- 

 ness of precious stones. Since they are 

 used, have been always used, and are a very 

 important article of commerce and industry, 

 he tells us all he knows about them or has 

 been able to gather from other authors ; ori- 

 gin, properties, classification, prices, trade, 

 pawns, sumptuary laws, size, collections, 

 crown-jewels, secular and sp.crcd uses, their 

 place in literature, mystical properties, and 

 engraving on precious stones. Many his- 

 torical facts are given which make the book 

 very readable and interesting. The above 

 subjects are distributed in the first nine 

 chapters. The following chapters are de- 

 voted to the description and histories of the 

 different varieties of precious stones. Among 

 these the diamond occupies the first place. In 

 two chapters the history, home, mining, trade, 

 polishing, etc., of the diamond are minutely 

 given, accompanied by much historical infor- 

 mation. Another is devoted to historical 

 and remarkable diamonds. The history of 

 each of these stones — or as much as is 

 known — is civen in each case. The record is 

 not what would be considered tlic best part 

 of human nature. Murder, wars, artifice, 

 theft, plunder, and treachery are the jewels 

 on which the larger number of these re- 

 markable diamonds arc set, and very few of 



these historical diamonds have a clean his- 

 tory. The largest diamond known is the 

 Braganza,orKing of Portugal, weighing from 

 sixteen hundred and eighty to eighteen hun- 

 dred and eighty carats uncut, the genuine- 

 ness of which is, however, doubted. There 

 are two, the Matan and Nizam, weighing 

 over three hundred caiats, uncut, and seven, 

 four of which are cut diamonds, weighing 

 between two and three hundred carats. The 

 diamond loses about one third of its weight 

 by cutting. 



The diamond is pure crystallized carbon. 

 The stones which belong to the class of the 

 precious corundum, which is supposed to be 

 nearly pure alumina, arc the most valuable 

 after the diamond. They are sapphire, as- 

 teria, emerald, amethyst, topaz, and ruby. 



The beryl class includes several varieties: 

 the emerald, acquamarincs, and topaz, which, 

 to distinguish them from those of the corun- 

 dum species, arc termed Occidental, while 

 these arc termed Oriental. The difference in 

 composition is that the beryl species contain 

 silica and other substances besides alumina. 

 Opals and pearls : spinet, garnet, tourma- 

 line, turquoise, lapis-lazuli, chrysolite, chrys- 

 oberyl, iolite, kyanite, apophyllite, labrador- 

 ite, and other gems, and the crystals of the 

 quartz family, are described in the last four 

 chapters. 



There are six appendices, giving the size 

 of the largest diamonds ; classification of 

 precious stones according to their constit- 

 uents ; hardness, and specific gravity, and 

 relative hardness, relative specific gravity, 

 localities in the United States where gem- 

 minerals have been found. 



Mind, No. XI/V. January, 1887. London: 

 Williams k Norgate. 



The present number is unusually rich. 

 The leading article is by Professor Wiliiam 

 James, of Harvard University, entitled 

 " The Perception of Space." Professor 

 Henry Sidgwick writes a criticism upon Dr. 

 Martincau's ethics, and James Ward, author 

 of the article upon psychology in the new 

 edition of the " Encyclopaedia Britanniea," 

 replies to some comments of Professor Bain 

 upon his work. J. M. Cattcll, Ph.D., con- 

 tributes an account of some interesting 

 experiments on the association of ideas. 

 Five critical notices by Professor A. Seth, 



