394 Geological Society . 



isomorphous substances, the nature of physical isomerism, and 

 morphotropy are discussed. Many of these chapters, especially the 

 historical ones and those dealing with isomorphism, are highly 

 interesting, and the author and translator have kept in touch with 

 the important recent work of Muthmann, Eetgers, Roozeboom, 

 and Tutton, so that on the whole the book is well calculated to 

 afford the student a glimpse into a new and but little explored 

 territor}'. Within the compass of 190 short pages it is, however, 

 impossible to deal adequately with all branches of the subject, 

 and much of the book, particularly the first half of it, is open to 

 criticism on the ground of extreme sketchiness ; too often also the 

 author has failed to distinguish between the essential and the 

 unimportant, and the student must be on his guard against accept- 

 ing as proven dogmatic statements unsupported by evidence. 



The inaccuracies of the Grerman edition have for the most part 

 been corrected. It is, however, unfortunate that the axial ratios 

 of meta-dinitrobenzene should still be assigned to tri-nitrobenzene 

 at the end of the account of Friedlander's work introduced to 

 illustrate the sort of aid the organic chemist may obtain from the 

 crystallographer. The chemist will, we fear, find at first sight 

 some difficulty in tracing the obvious crystallographic relations 

 which he is told exist, and will hardly be sufficiently impressed 

 with the value of such researches. 



The author's preface to the German edition is not translated, 

 its place being apparently taken by an introduction from the pen 

 of Professor Story-Maskelyne, in which the objects of the book 

 are set forth, and attention called to the results of van't Hoffs 

 work, and to the importance of the study of mixed crystals and 

 double salts. 



Paper and printing leave nothing to be desired, and in spite of 

 defects this little book ought to be in the hands of all advanced 

 students of chemistry, and should stimulate many to take an 

 interest in a fascinating subject, rich in problems awaiting solution. 



XXXIII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 320.] 



June 19th, 1895.— Dr. Henry Woodward, F.It.S., President, 



in the Chair. 

 HPHE following communications were read : — 

 ■*■ 1. ' On the Occurrence of Radiolaria in Chalk.' By W. Hill, 

 Esq., F.G.S., and A. J. Jukes-Browne, Esq., B.A., F.G.S. 



2. « The Crush-Conglomerates of the Isle of Man.' By G. W. 

 Lamplugh, Esq., P.G.S. ; with an Appendix by W. W. Watts, Esq,, 

 M.A., P.G.S. 



The Skiddaw Slates of the Isle of Man have everywhere under- 

 gone intense shearing, and on the north-west side of the main 

 stratigraphical axis actual disruption of the bedding with the 

 resultant formation of breccia or crush-conglomerate on a large 

 scale has taken place. Thb structure attains its widest develop- 



