470 



SCIENCE, 



[Vol. V., No. 122 



chalk where the infusorial silica occasionally 

 segregates into cracks instead of into flint 

 nodules. 



The breaking-clown of the material of the 

 walls of vein-fissures, its alteration, and incor- 

 poration, in place, into the gangue, are briefly 

 but well described, and illustrated by drawings 

 made from thin sections under the microscope. 

 Much weight is given to the results of Sand- 

 berger's researches, which seem to establish 

 quite firmly lateral secretion as the generally 

 most important method of vein formation and 

 enrichment. Mr. Phillips gives in this con- 

 nection a very instructive resume of some of 

 Sandberger's results, which show the wide- 

 spread distribution of both the heavy metals 

 and the elements of the gangue substances 

 in the constituent minerals of the common^ 

 rocks. 



Not less interesting are the instances cited 

 to show the sufficiency of causes acting now 

 and in recent times at the surface of the earth, 

 to cause the concentration and fixation of 

 minerals to form ore-bodies. 



Thus the fact shown by Sandberger, that all 

 lithia micas contain tin, taken in connection 

 with the finding, in various Cornish stream- 

 works, of (leer's antlers completely replaced 

 by crystallized oxide of tin, points at once to 

 the existence of sufficient sources of tin in 

 surface rocks, and to the possibility of deriva- 

 tion from those sources, and concentration in 

 veins and stock-works, under conditions now 

 prevailing at the surface. So, also, in the 

 instances of metallic gold which have been 

 found deposited on the woodwork of Austra- 

 lian mines, we have similar evidence of metal- 

 lic deposition now in progress. 



While Mr. Phillips considers that the evi- 

 dence is largely in favor of assigning to lateral 

 secretion the generally most important part in 

 forming fissure-veins, he recognizes the prob- 

 able action of ascension, and also of sublima- 

 tion, in many individual cases. The portion of 

 the book — about five hundred pages — devoted 

 to the description of t} T pical forms of deposits 

 throughout the world is full of information 

 desired by the economic geologist and the 

 statistician. 



The illustrative instances are well selected, 

 and the latest available statistics of production 

 are given, apparently, in all cases. Aside from 

 the fact that it brings the description of the 

 countries treated by Cotta down to the present 

 time, the book is particularly valuable for its 

 descriptions of practically all countries which, 

 for various reasons, received little or no atten- 

 tion in Von Cotta' s work. 



THE MICROSCOPE IN BOTANY. 



Those students who have been waiting for 

 an English translation of Behrens's book on 

 botanical methods can but be disappointed 

 now that it has appeared. Not that the book 

 does not contain much that is extremely valu- 

 able, nor that it is not put in an attractive form 

 by the publishers, but that it has been made 

 cumbersome and expensive by an inordinate 

 amount of ' padding ' not found in the German 

 text. Figures and descriptions of American 

 instruments are introduced with such careful 

 discrimination, that doubtless the volume must 

 prove eminently satisfactory to their makers, 

 while the author's remarks on the more useful 

 stands of continental make are entirely sup- 

 pressed, possibly from a laudable wish to fur- 

 ther home protection. The maxim of the 

 author, that " he is the best experimenter who 

 does his work with the simplest possible appa- 

 ratus," is frequently outraged by the descrip- 

 tion of gimcracks easily dispensed with, and 

 more properly advertised in an instrument- 

 maker's catalogue than in the pages of an ex- 

 pensive handbook. 



Yet, notwithstanding the fact that a two- 

 dollar-and-a-half book has been evolved into a 

 five-dollar book by a process the reverse of 

 natural selection, the translation must prove a 

 boon to the few investigators who have not 

 sufficient command of German to use the origi- 

 nal ; and it is unquestionably more convenient 

 for college students, who, as a rule, dread man- 

 uals in any language but their own. Those 

 who use the book in either form will probably 

 agree with the author that the chapters on re- 

 agents and their application in microchemical 

 work constitute its most valuable feature, ren- 

 dering it, indeed, indispensable in the labora- 

 toiy where careful work is carried on. A 

 chapter on the preparation of specimens for 

 examination and preservation is also extremely, 

 useful, and especially the portion treating of 

 the preparation of fossils and other hard ob- 

 jects. 



Though a few more or less deserved slurs oh 

 English microscopists, and the author's all but 

 complete forgetfulness that Americans ever 

 look through the instrument, may touch the 

 pride or appeal to the belligerence of an Anglo- 

 American, the book is, in the main, written 

 well and in good taste, and shows a working 

 familiarity both with the subjects handled and 

 the literature pertaining to them. 



A guide to the microscopical investigation of vegetable sub- 

 stances. From the German of Dr. Julius Wilhelm Behrens. 

 Translated and edited by Rev. A. B. Hervey, A.M., assisted by 

 R. H. Ward, M.D., F.R.M.S. Boston, Cassino, 1885. 



