

Miscellaneous Intelligence. 325 



For instance, 0-00003 mgrm. of manganese is volatilized by one 

 spark discharge, and yields a spectrum with the following ulti- 

 mate group of lines : 2949-3, 2939-4, and 2933-1. 



As no atmosphere is free from dust, and that of cities is 

 particularly dusty, these mineral constituents must be regarded 

 as possible reagents in cases where there is evidence that very 

 minute quantities of basic substances can initiate chemical 

 reactions and isodynamic changes, such as have generally been 

 considered as spontaneous, and in all cases where a solution in 

 contact with air is liable to be affected." 



8. Crystallography and Practical Crystal Measurement ; by 

 A. E. H. Tutxon. Pp. xiv, 946, with 720 figures, and 3 plates. 

 London, 1911 (Macmillan & Co. Ltd.). — The student of crystal- 

 lography, desirous of making himself familiar not only with the 

 theoretical facts and principles but also with the practical methods 

 of studying crystals, morphologically and physically, will find in 

 the present volume a most satisfactory guide. It begins with a 

 discussion of the preparation and collection of crystals, and then, 

 before taking up the questions of symmetry and form, deals with 

 the goniometer, so as to make the student acquainted at once 

 with a method of handling and studying crystal forms. From 

 this starting point practical examples are given under each sys- 

 tem of the treatment of a typical case, carried out in all necessary 

 fullness of detail. Under the triclinic system, for example, copper 

 sulphate is taken, and the successive steps detailed from the meas- 

 urement of the angles in the different zones to the calculation of 

 the axial ratio and the description of the individual faces. The 

 drawing of crystals is treated in the same clear, minute way. 



The second part of the work is devoted to the physical side of 

 the subject, and here also we have all necessary theoretical dis- 

 cussions coupled with full explanations as to the successive meth- 

 ods of experiment called for. The illustrations in the volume 

 are particularly satisfactory, having been drawn by the author 

 expressly for this work. The interference figures are represented 

 in black and white in a series of plates made from excellent pho- 

 tographs, and throughout the mechanical execution of the work 

 is up to the high standard of the subject matter. 



III. Miscellaneous Scientific Intelligence. 



1. Mendelism ; by JR. C. Punnett. Third edition, entirely 

 rewritten and much enlarged. Pp. xiv, 192, with colored plates 

 and diagrams. New York, 1911 (The Macmillan Company). — 

 The general recognition of the wide applicability of Mendel's 

 discoveries has given a great impetus to the experimental 

 breeding of plants and animals during the past decade. The 

 wonderful results which have come from these experiments have 

 so far changed the earlier conceptions of the nature of the hered- 



