456 RECORD OF SCIENCE FOR 1887 AND 1888. 



angle of extmctioii in crystal sections cut in different directions, and 

 other related subjects. The first part is thus theoretical ; the second 

 gives a concise summary of the characters, chiefly physical, of rock- 

 making mineral species. This part of the work contains many original 

 observations by the authors of the optical constants, indices of refrac- 

 tion, absorption, and so on. Eosenbusch has also issued a set of tables 

 giving in compact form the microscopical characters of all important* 

 minerals; ^ these will be found of great i)ractical use by the worker in 

 this line of research. 



Related to the works mentioned is that of Teall on British Petrog- 

 raphy, an extended and well illustrated volume, but too exclusively pet- 

 rograi)hical to call for more than simple mention. Other important pet- 

 rographical works are those of Eosenbusch (Die massigenGesteine, 1887) 

 and Eoth (Allg. und cbemische Geologic, vol. 2, 1887). 



The work of Goldschmidt^ on Crystallography and the forms of crys- 

 talline minerals is without question the most extended which has ever 

 been undertaken in this field. The author has developed a new sys- 

 tem of crystallographic notation, simply related to those in common use, 

 and designed to exhibit especially the relations of the forms of a crys- 

 tal as given in the projection. In connection he hasdeveloped a method 

 of calculation adapted to this notation, and further has given a thorough • 

 discussion of the various systems that have been in use from the ear- 

 liest time down. This forms the first half of the first volume, after 

 which begins the work proper, namely, the catalogue for each species 

 of all the planes that have been observed with the literature, the letters 

 and other notation of different authors, the equations for transforma- 

 tion, and so on. The species are arranged alphabetically, and the whole 

 work is to consist of three large volumes. The working mineralogist 

 will profit to no small degree from the author's labors, though the fact 

 that neither figures nor angles are given, and that theoretical consid- 

 erations have often led to a variation from the commonly accepted 

 method for the orientation of the crystals of a species will restrict its 

 usefulness. 



Several volumes on local mineralogy have recently appeared. The 

 Russian Mineralogy ^ of von Kokscharof has now entered upon its tenth 

 volume, and although the veteran author celebrated his fiftieth anni- 

 versary of active service in 1887 he is still carrying forward his labors 

 with vigor. The present state of knowledge in regard to the mineralogy 

 of India is well presented by F. R. Mallet,' in a volume devoted to this 



1 HUlfstabellen znr mikroskopisclien Mineralbestimraung in Gesteincn. Stuttgart, 

 1888. 



^ludex tier Krystallfonnen tier Miueralieu, vol. i, 1886; vol. ii, Nos. 1-4, 1883; 

 vol. Ill, Nos. 1-3, 1888. 



^Materialieu ziir Minevalogie Russlautls, vou N. vou Kokscbarow, 1888, vol. 10, pp. 

 1-224, I 



< A Manual of the Geology of India, part iv, Mineralogy (mainly non-economic), by 

 F. R. Mallet, 179 pp., with 4 plates. Calcutta, 1888. • 



