Oeology and Mineralogy. 225 



1 6, Manual of Introductory Chemical Practice, for the use of Stu- 

 dents; by George C. Caldwell, S.B., Ph.D., Professor of Agri- 

 cultural and Analytical Chemistry, and Abram A. Brenemak, 

 S.B., Assistant Professor of Applied Chemistry in Cornell Univer- 

 sity, Ithaca, N. Y. Published by the authors. 124 pp. 12mo. 

 1875.— This manual is an experiment on the part of the authors in 

 a novel mode of chemical instruction, devised by them, with a 

 view to cultivate on the part of the student habits of careful 

 observation, attention to and appreciation of phenomena, and the 

 deduction of legitimate results. In short it seeks to make the stu- 

 dent his own teacher by simple synthetic or analytic experiments, 

 and to lead him on by easy steps to an understanding of principles 

 and of chemical philosophy — in a way unattainable from text- 

 books alone. The student is required to give his results and con- 

 clusions in writing, an excellent w^ay to secure accuracy and con- 

 ciseness of statement. He is presumed to be in attendance on a 

 reciting at the same 



IT. J^ote on the Electrical Conductivity of Saline Solutions ; 

 by J. G. MacGkegor, M.A., B.Sc, Communicated to the Royal 

 Society of Edinburgh, May 17, 1875; by Professor Tait (Proc. 

 Roy. Soc. Edinb., 1875, 645.)— This note is a reply to criticisms 

 by Professor Beetz published in the Sitzungsberichte of the Ber- 

 Im Academy (and in Poggendorff's Annalen) on a paper of Mr. 

 MacGregor's published in the Transactions of the Edinburgh 

 Royal Society, xxvii, pp. 51-70. Mr. MacGregor shows that the 

 criticisms are based in part on a misunderstanding of his paper 

 and of his method of experimenting. 



II. Geology and Mineralogy. 



1. Supposed Agency of Ice-Floes in the Champlain Period; 

 by Professor A. Winchell, Syracuse, N. Y.— I have lately dis- 

 covered some new instances of huge limestone masses, anomalously 

 detached from the formation to which they belong; and have em- 

 braced references to localities, in a paper read before the American 

 Association at Detroit. These are masses of Carboniferous lime- 

 '- from 10 to 60 feet in length and often of unknown thickness, 



to believe, 

 must be genuine exposures of the formation, in place ; but others, 

 by being worked out, or by their downhill dip, far exceeding, and 

 disagreeing with, the normal dip of the formation, are demonstra- 

 bly dissevered and displaced portions of it. For exara])]e, one re- 

 gion of exposures of this class^ in the town of Claybanks, is withm 

 half a mile of the shore of Lake :MichiLraii, wliere we have a bluflf 

 250 feet in height, and attainiiiy, a lew r...ls back, an elevation of 

 2t5 feet, serving as a station of the V. S. Lake Survey. The vicin- 

 ity, for miles around, is elevated 250 to 300 feet above the lake. 



