January 12, 1900.] 



SCIENCE. 



71 



crystals based on the principles of symmetry. 

 It is devoted exclusively to the geometrical re- 

 lations of crystal forms and to methods of de- 

 termining these relations and of representing 

 them graphically. 



In the first niue chapters the general proper- 

 ties of crystals are described, including very 

 full discussions of symmetry relations and of the 

 properties of zones. The discussion is geomet- 

 rical rather than analytical and follows more or 

 less closely the treatises of Miller and Story- 

 Maskelyne. In Chapters VI. and VII. , treating 

 of crystal di-awing and methods of projection, 

 no mention is made of the gnomonic projection, 

 which now occupies an important place in crys- 

 tallographic discussion. 



The treatment of the general optical and 

 physical properties of crystals of the different 

 systems contained in Chapter X. is very brief 

 and seems hardly adequate in a work of this 

 character. 



Chapters XI. to XVIII. are devoted to de- 

 scriptions of the thirty-two classes of crystals. 

 The classification of these types is essentially 

 that of Groth. A feature of this part of the 

 work is the presentation of a great many ex- 

 amples of crystals of various substances in each 

 class, each crystal being worked out in detail 

 with all the logarithmic computations necessary 

 for the determination of its elements and the 

 indices of its forms. Directions for drawing 

 the forms are also not infrequently given after 

 their determination, and a great deal of useful 

 information in practical crystallography may 

 be found scattered through these examples. 

 But their number seems rather more than 

 necessary, adds very much to the bulk of the 

 book and so scatters the desired information as 

 to reduce its usefulness. 



In the final chapter on Goniometers but scant 

 justice is done to the theodolite goniometer, no 

 reference being made to the admirable graphic 

 methods of discussing measurements made with 

 it developed by Federow and Goldschmidt. 



A complete index concludes the volume. 

 The excellent typography and text figures de- 

 serve a word of praise. 



The book hardly commends itself to begin- 

 ners in crytallography, being too elaborate in 

 its treatment and too mathematical in its pres- 



entation. Its greatest service will be to more 

 advanced students doing practical work in the 

 study of crystals. 



C. Palachb. 



SCIENTIFIC JOURNALS AND ARTICLES. 



The contents of the American Journal of Sci- 

 ence for January are as follows : 



' Products of the Explosion of Acetylene,' by W. 6. 

 Mixture. 



' Glaoiation of Central Idaho, ' by G. H. Stone. 



' Pogonia Ophioglossoides, ' by T. Holm. 



'Graftonite, a new 'Mineral from Grafton, New 

 Hampshire, and its Intergrowth with Triphylite,' by 

 S. L. Penfield. 



' Explorations of the Albatross in the Pacific Ocean, " 

 by A. Agassi z. 



' Analyses of Italian Volcanic Eocks, II.' ; by H. 

 S. Washington. 



' Constitution of the Ammonium Magnesium Arse- 

 niate of Analysis, ' by M. Austin. 



The Astrophysical Journal for December con- 

 tains the following articles : 



' Robert Wilhelm Bunsen,' by Henry Crew. 



'The Wave-Length of the Corona Line,' by C. A. 

 Young. 



'Density of Close Double Stars,' by Alexander 

 Roberts. 



' The Densities of the Variable Stars of the Algol 

 Type, ' by Henry Norris Russell. 



' Note on the Spectrum of P. Cygni,' by A. B^lopol- 

 sky. 



' Apparatus and Method for the Photographic 

 Measurement of the Brightness of Surfaces, ' by J. 

 Hartraann. 



'The Great Sun-Spot of September, 1898,' by J. 

 Fenyi. 



' A Spectroscope of Fixed Deviation,' by Ph. Pellin 

 and Andre Broca. 



' Researches on the Arc-Spectra of the Metals,' by 

 B. Hasselberg. 



The contents of Appleton's Popular Science 

 Monthly for January include ' The Advance of 

 Astronomy in the Nineteenth Century,' by Sir 

 Robert Ball, ' The Applications of Explosives,' 

 by Professor C. E. Munroe, ' Scenes on the 

 Planets,' by Mr. Garrett P. Serviss, Professor 

 Warden ' Naturalism and Agnosticism,' by Mr. 

 Herbert Spencer, and ' Old Rattler and the King 

 Snake,' by President David Starr Jordan. The 

 Monthly is somewhat altered in appearance, and 

 the price is $3.00 per annum. We trust that its 

 influence may be correspondingly increased. 



