86 Reviews — 0. C. Farrington s Meteor lies. 



and Mauch Chunk. One must also be grateful for some admirably 

 written sections on the beginnings of earth-history by Professor 

 Barrel!, and for a well-illustrated chapter on Dinosaurs by Professor 

 U,. S. Lull. In brief, this is an original and stimulating book, 

 where fact and theory are happily mingled, and the tangled threads 

 of many complicated series of events reduced to an orderly and 

 attractive pattern. 



III. — Meteorites : their Structure, Composition, and Terrestrial 



Relations. By 0. C. Farrington. pp. x, 233, with frontispiece 



and 65 figures in text. Chicago: published by author, 1915. 



Price 8s. 6d. 



TIIHE absence of a comprehensive and up-to-date book on meteorites 



\ has undoubtedly been a factor in confining the interest in this 



subject to a comparatively small number of geologists. The admirable 



introduction to this study in the handbook to the collection in the 



Natural History Museum is of course limited in scope, while Cohen's 



Meteor itenkunde, which was intended to cover the full ground of the 



subject, was unfortunately little more than half finished at the 



author's death. Dr. Farrington' s book, therefore, fills a gap in 



scientific literature and will be indispensable to the student who 



desires a general knowledge of the subject. 



The book opens with a discussion of the criteria whereby meteorites 

 may be distinguished from terrestrial material, and emphasis is laid on 

 the superficial and chemical characteristics by which the former may 

 be discriminated when, as is generally the case, the fall has not been 

 observed. Several chapters are devoted to the fall of meteorites, 

 while the succeeding sections are concerned with the form and size of 

 these bodies. As is to be expected, the discussion of the composition 

 and structures is very full, the explanation of the octahedral structure 

 so common in 'irons' and the account of the structures found in 

 'stones' being admirably lucid. In the description of the mineral 

 species a large amouut of space is devoted to the three types of nickel- 

 iron, but this constitutes the least satisfactory portion of the book. 

 Thus plessite is explained by analogy with the system silver-copper, 

 as a eutectic developing probably from solid solution, but no mention 

 is made of the recent metallographic work on the system iron-nickel. 1 

 The investigations of Osmond and Cartaud, Tammann, and particularly 

 Buer have shown that 7-iron and /3-nickel are isomorphous and that 

 this solid solution on cooling undergoes a number of changes in the 

 solid state, a-iron and a-nickel, the low-temperature forms, also 

 give solid solutions, and kamacite is to be regarded as a nearly saturated 

 solid solution of a-nickel and a-iron, and not, as Dr. Farrington hints, 

 as a compound of constant composition, NiFe 14 . The only compound 

 in the system has the composition Fe Ni, and taenite is considered to 

 be a solid solution of a-iron and this compound, while plessite is 

 a eutectoid of kamacite and taenite, separating from solid solution. 



1 A useful summary of this is given by Desch, Metallography , 2nd ed., 1913, 

 pp. 383-5. 



