Geological Society. 703 



Verfliissigtes Ammonialc als Losungsmittel. Von J. Beonn. Berlin : 

 Julius Springer. 1905. Pp. xi + 252. 



The author of this book is to be congratulated on having written 

 a very useful monograph dealing with the properties and methods 

 of handling liquid ammonia, and with its applications as a solvent. 

 Hitherto no sufficiently detailed information on these subjects 

 was available without a very laborious search through the chemical 

 literature of the past forty years ; and we can cordially recommend 

 the book to all chemists who are either interested in the subject 

 in a general way, or who may be engaged on experiments in 

 connexion with which the solvent properties of liquid ammonia 

 would prove useful. A special chapter is devoted to the uses of 

 liquid ammonia in physico-chemical researches. 



LXXVIII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 616.] 



June 7th, 1905.— J. E. Marr, Sc.D., E.R.S., President, 

 in the Chair. 

 ^TVEEE following communications were read : — 



1. ' The Microscopic Structure of Minerals forming Serpentine, 

 and their Relation to its History/ By Prof. T. Gr. Bonney, Sc.D., 

 LL.D., E.R.S., V.P.G.S., and Miss C. A. Raisin, D.'Sc. 



The authors, after a brief reference to investigations of serpentine 

 during the last thirty years, which still leave some points unsettled, 

 describe the formation of that mineral from, sundry ferromagnesian 

 silicates. Having given a summary of the changes in olivine, they 

 describe more fully the alteration of separate grains in the so-called 

 ' kimberlite' of South Africa. Then, after referring to the serpen- 

 tinization of amphibole, as illustrated in the well-known Rauenthal 

 rock, they enter more fully into the changes, first, of the orthorhombic 

 pyroxenes ; then of the monoclinic. To illustrate the latter, they 

 describe the conversion of malacolite into serpentine in the well- 

 known ' Eozoon '-rock of Cote St. Pierre, and of some augite-bearing 

 serpentines in the Yosges. An investigation follows of the form of 

 serpentine called ' antigorite,' described by Dr. Hussak (in 1883) 

 from Sprechenstein on the Brenner Pass, and asserted to exhibit a 

 'netting-like' (gestrickte) structure, which is a record of the 

 nearly-rectangular cleavage of the original augite. They show, 

 by study of specimens collected in the Sprechenstein district by 

 Miss Raisin, that no such connection exists and that the netting-like 

 structure has often only a subjective existence. 



The mica-like mineral called antigorite is shown to be abundant 

 in the Pennine Alps about the head of the Vispthal, and to lead to 

 the same conclusion, suggesting, no less than the Sprechenstein 

 specimens, a relation between that mineral and pressure. After a 

 brief notice of the chemical chancres in the conversion of the various 



