Geology and Mineralogy. 303 



physics, which enabled him in this first volume to develop with 

 unusual clearness and method the principles involved in physical 

 phenomena, has now aided him in the description of a series of 

 laboratory experiments for college classes. This work, in the pre- 

 paration of which he has been associated with Dr. Bliss, is on a 

 decidedly higher level than most of those which have been 

 published hitherto. The experiments are selected with judgment 

 and the method of presentation has much to be recommended, 

 not only in the fullness and accuracy of statement but still more 

 as regards the prominence given to the statement of the general 

 theory involved in each and the object for which it is periormed. 

 In developing these points, reference is constantly made to the 

 companion volume, and the student who uses the two works con- 

 scientiously cannot make the mistake so common of performing 

 an experiment blindly, without understanding why it has been 

 done or what physical principles it illustrates. Each experiment 

 is accompanied by a practical illustration, drawn out numerically 

 in full, and a series of questions and problems follow ; these last 

 bear particularly upon the sources of error involved and the 

 degree of accuracy possible in each case. 



II. Geology and Mineralogy. 



1. Recent Publications of the CT. S. Geological Survey* — The 

 Eighteenth Annual Report for 1896-7 has five parts, of which 

 Part i, Report of the Director; Part v, Mineral Resources, and 

 two papers of Part iii, Economic Geology, have already been 

 issued. The remaining papers of Part iii, and Part iv, Hydrog- 

 raphy, will soon appear. Those of Part ii are of a theoretical 

 nature and will appear last. The report of the Director with 

 an appendix on Triangulation and Spirit leveling contains 440 

 pages with two maps showing the condition and progress of 

 astronomic location, primary triangulation, traverse and precise 

 leveling, topographic surveys, and gauging stations. The total 

 appropriation for the work of the Survey during the year was 

 $568,690, of which $184,200 was for topography, $118,700 for geol- 

 ogy, $14,000 for paleontology, $10,000 for chemistry, $50,000 

 for hydrography, and $30,000 for preparation of report on min- 

 eral resources. There were thirty geological field parties in as 

 many States and Territories. Most of the geologists continued 

 the areal and structural work of former years. N. S. Shaler com- 

 pleted his in vesti stations on Cape Cod and took up the Mesozoic 

 coal basin near Richmond, Va. ; B. K. Emerson extended his 

 work in Mass. ; T. Nelson Dale in eastern New York and Vt. ; 

 J. F. Kemp in the Adirondack region ; W. H. Hobbs in western 

 Mass. and Conn. ; J. E. Wolff, assisted by A. H. Brooks, cooper- 

 ating with the State Survey in New Jersey ; M. R. Campbell, 

 assisted by J. A. Taff and W. C. Mendenhall, in Kentucky and 



* Issued since May, 1897. See lists in this Journal for Aug. 1897, page 155, 

 and for Nov. 1897, page 392. 



