JRevieus — Milne's Crystallography. 373 



succeeded by the Brown-coal series, the oldest horizon of which is 

 decidedly Middle Oligocene ; and the Eocenes, strictly so called, are 

 wanting there. The whole discussion, adds Prof. Heer, proves the 

 necessity of ascertaining with more precision the age and geological 

 position of the Tertiary florae in each locality. At all events, the 

 present exact knowledge of the North-Polar Tertiary florae, he says, 

 has been highly profitable to Geology in proving the needlessness of the 

 hypothesis of a formerly existing " Atlantis." T. E. J. 



IE, IE "V I IE "W S. 



I. — Notes on Crystallography and Crystallo-physics. By 

 John Milne, F.G.S. (Professor of Geology and Mineralogy in 

 the Imperial College of Engineering, Yedo, Japan.) 8vo. pp. 80 ; 

 25 Woodcuts. (London : Triibner & Co., 1879.) 



THE study of Geology is a wide one, implying a foreknowledge 

 of Biology, Chemistry, Physics, and Mineralogy, and to be well 

 acquainted with all these is rarely the lot of one man ; therefore, 

 when a geologist writes a book on Crystallography and Crystallo- 

 physics, it is apparent that there must be a considerable want felt 

 by geologists for a work of this kind, viz. one which,, while deserting 

 the awkward system of Naumann still taught in preference to any 

 other by several of our teachers of mineralogy, and using the elegant 

 system of Neumann and Miller, yet attempts (to use Mr. Milne's 

 own words) '•' to give the general principles which crystallographical 

 calculations involve for the use of those students who wish to know 

 them, rather than for those who wish actually to employ them " 



It is to be regretted (for the sake of the author) that the publication 

 of Mr. Milne's Crystallography was delayed, owing to his absence 

 from England, as, when the lithographed notes of these lectures 

 delivered in Japan were sent to England for publication "in the 

 Geological Magazine, or elsewhere," Mr. Gurney's little book on 

 Crystallography had not yet appeared. Had they been printed in this 

 country earlier, they would have taken precedence in publication of Mr. 

 Gurney's pamphlet, as they undoubtedly do in date of issue in Japan. 



The author expresses himself indebted for information to Prof. 

 Miller's Treatise on Crystallography, and Prof. Maskelyne's Lecture- 

 notes on the Morphology of Crystals ; he might also have cited Prof. 

 Miller's Tract on Crystallography, which, though shorter, is pre- 

 ferable to his Treatise, at least from a mathematician's point of 

 view. 



Important as the study of Lithology has now become to geologists, 

 we hope to see Mineralogy studied by them in a truly scientific 

 manner, and this work we take as an indication that this has 

 begun. Whilst taking exception to the way in which Mr. Milne 

 has tried to avoid some of the difficulties of the subject— as on page 

 16, where the proof given applies only to those crystals belonging to 

 four out of the six existing systems, and the results of which are 

 used on page 25 in dealing with a crystal belonging to one of 

 the two excluded systems — we cannot but admire his courage in 



