490 Scientific Intelligence. 



Pp. 175, figs. 20. New York, 1912 (Cambridge University 

 Press ; (t. P, Putnam's Sons). — This book, as stated in the preface, 

 "is intended for those who are not specialists in geology, and it may 

 perhaps be accepted as a contribution for the general reader." 

 Besides a description of the composition of the chief rock types, 

 a full discussion is given of the manner of origin, the manner of 

 weathering, the types of scenery with which the rocks are asso- 

 ciated. The geologic meaning of the rocks is thus brought out, 

 and those features emphasized which are of chief interest, apart 

 from the mere classification which is a chief aim of so many texts. 

 It should serve to stimulate a general interest in the earth and its 

 history, presenting the subject of the description of rocks in a 

 most attractive and significant manner. j. b. 



13. The Origin of Earthquakes; by Ciiables Davison, 

 Sc.D., F.G.S. Pp. 'l44, figs. 26. New York, 1912 (Cam- 

 bridge University Press ; G. P. Putnam's Sons). — This is one of 

 the Cambridge manuals of Science and Literature. It is clearly 

 written, free from technicalities, and available for the general 

 reader. The fact that the author is a well-known student of 

 earthquakes gives it in addition an authoritative character. 

 Earthquake phenomena are described and examples are given of 

 different classes of earthquakes. The inferences as to origin are 

 discussed and the part which they play in earth movements. 



J. B. 



14. The Identity of Parisite and Synchisite ; by C. Palache 

 (communicated). — In a paper published in this Journal last year, 

 by Warren and Palache, describing the Quincy pegmatites, the 

 parisite of that locality was described fully and it was shown that 

 in all probability the mineral synchisite from Narsarsuk, Green- 

 land, was identical with it. This conclusion was not accepted by 

 the discoverer of the latter mineral, Dr. Flink, and he requested 

 a new analysis of synchisite for which he supplied material to 

 Dr. Warren. This analysis has not been made ; but meanwhile 

 the investigation has been completed elsewhere. 



E. Quercigh* has shown that the supposed chemical differences 

 between the two minerals are due to alteration products contained 

 in the analyzed synchisite ; that pure synchisite has the same 

 formula as parisite ; the same indices of refraction ; and the same 

 specific gravity. All grounds for maintaining the distinction 

 between the two are thus removed. 



The refractive indices, measured on prisms, are probably more 

 accurate than those previously recorded. 



Refractive indices of Parisite, Sodium light. 



Muso Narsarsuk Quincy 



(Synchisite) 

 Quercigh Quercigh Warren 



e 1-7712 1-7690 1-757 



w 1-6717 1-6730 1-676 



* Sulla identita della Sinchisite con la Parisite. Rend. d. E. Accad. Lincei 

 xxi, 581-588, 1912. 



