REVIEWS AND BOOK NOTICES. 



Chemical and Geological Essays. 1 — The manifest tendency 

 of modern scientific researches and investigations is toward a uni- 

 fication of the sciences, an I the volume forming the subject of 



and excellent text-books of geology as studied from the stand- 

 points of physics and biology ; but, with the exception of Bischof s 

 treatise on chemical geology, which appeared nearly a generation 

 ago, this is the nearest approach to a complete exposition of the 

 intimate relations and interdependence of geology and chemistry 



Tlie work comprises twenty of the author's chief scientific me- 

 moirs, which have been published at different times during the past 

 twenty-five years. They treat of questions in chemistry, and 

 chemical and dynamical geology, and, to quote from the preface, 

 "cover nearly all the more important points in chemical geology." 



velopcd in these memoirs have been connected with the hypoth- 

 esis of a cooling globe and with certain views of geological dy- 

 namics, making together a complete scheme of chemical and physi- 

 cal geology, the outlines of which will be found embodied in Es- 

 says I to XIII." Essays XIV and XV are chiefly historical, while 

 the five brief papers which conclude the volume are devoted to the 

 discussion of questions in theoretical chemistry and mineralogy. 



In addition to the development of his own ideas, Dr. Hunt has 

 in general given us the results achieved by his co-laborers, so that 

 the work is in truth a fair representation of the present state of 

 the science. Several of the more recently developed of our au- 

 thor's views, as those concerning the use of lithologic data as a 

 basis t ,i chronologh distinctions, md his the on of cycles n >< li- 



nimeralogieal data forming the basis of these hypotheses, however, 



abled to form an intelligent judgment concerning the truth of 

 these hypotheses. 



Essay XV on the " History of the names Cambrian and Silurian 



