PETROLOGICAL ABSTRACTS AND REVIEWS 465 



place of Groth's classical Physikalische Krystallographie, and it is with 

 great pleasure that this translation of certain parts is welcomed. The 

 only criticism that can be made is that Professor Jackson did not trans- 

 late the entire work. 



The translation, in general, follows the form of the original and 

 includes all of the "Optical Properties" in Part I, with additions, here 

 and there, from the parts in the original devoted to systematic descrip- 

 tions of crystals and methods of crystal investigation. The translation 

 seems to be good, although, in places, the sentences, closely following 

 the German, are rather long. A slight error is introduced, on p. 15, 

 where the number of vibrations per second of red and violet light are 

 spoken of, by the translation of the German billion (io 12 ) as billion 

 (10'). 



The book is well gotten up, and the line drawings, apparently from 

 wax plates, are sharp and clear. 



Albert Johannsen 



Howe, J. Allen. The Geology of Building Stones. New York: 



Longmans, Green & Co.; London: Edward Arnold, 19 10. 



i2mo, pp. viii+455, pi. 8, maps 7, figs. 31. 



This work, the fourth of Arnold's Geological Series, under the 



general editorship of Dr. J. E. Marr, apparently is intended primarily 



for architects. It treats of the rock-formi-ng minerals and the rocks in 



non-technical language and gives the principal properties of each. 



The decay of building stone is discussed, and methods of testing are 



described. The author says, "There is no help: sooner or later, in the 



course of practice, the architect or engineer will have the need of some 



geological knowledge forced upon him." If the little knowledge is not 



a dangerous thing, this book may serve a useful purpose. 



Albert Johannsen 



Lacroix, A. "Le cortege filonien des peridotites de la Nouvelle 

 Caledonie," Comptes Rendus de VAcademie des Sciences, 

 CLII (1911), 816-22. 

 The peridotites of Nouvelle Caledonie are cut by narrow dikes form- 

 ing a gabbroic and a dioritic series. In both, gradations can be traced 

 between a leucocratic extreme (anorthosite) and a melanocratic extreme, 

 (pyroxenite or hornblendite). Nine analyses are given which prove 

 that six of the rocks fall into previously unnamed subdivisions of the 



