June 23, 1904] 



NA TURE 



175 



showing the variation in composition, even in samples 

 from the same locality. The only stone which has as 

 yet been found to fill all the requirements of the litho- 

 grapher's art is that from Solenhofen, in Bavaria. In 

 the United States materials of the nature of litho- 

 graphic stone have been reported from a number of 

 localities described by the author. While, however, it 

 w.is ]50ssible to get small pieces suitable for trial pur- 

 poses, every locality has failed, as a constant source of 

 supply of the commercial article. Very encouraging re- 

 ports come from Canadian sources, and it is possible 

 that a considerable lithographic stone industry may yet 

 be developed in the Dominion. 



Kssais des Metaiix, Thcorie ct Pratique. By L. Gages, 

 Chef d'escadron d'.Xrtillerie. Pp. i68. (Paris : 

 Ciauthier-Villars, no date.) Price 3 francs. 

 This little work, the sixth of the " .\ide-Memoire " 

 scries on metals, by the same author, is written with 

 much of the charming clearness of diction generally 

 found in French metallurgical writings. There are two 

 parts, the first on the theory of the tests and the second 

 on practice. Considering the size of the page (con- 

 venient for the pocket), the matter is wonderfully well 

 treated. Thus, to take the tensile test as an example, 

 there is a general heading. Preliminary Ideas, with 

 paragraphs (i) Period called Elastic, (2) Period of De- 

 lormation, (3) Contraction, (4) Curv-e of Traction. In 

 this last is worked out from the ordinary tensile curve, 

 showing elongation and tons per square inch on the 

 original section, a curve showing tons per square inch 

 on the real section, thus making plain to the student the 

 reason for the apparently paradoxical form of the 

 ordinary curve. The next main heading is the Law of 

 Similitude, treated under six subheadings, the first 

 of which, for example, considers the two permanent 

 elongations produced during tensile testing. These 

 two very distinct elongations are not only made clear, 

 but methods are given for their determination, and the 

 steps in the reasoning are worked out by simple 

 mathematical methods where necessary. In like 

 manner are handled such subjects as elasticity, in- 

 Huence of temperature, repetition of stresses, distri- 

 hulion of deformations, augmentation of elastic limit. 



Part ii., on practice, treats in a general way of the 

 tests applied by engineers before accepting cast-iron, 

 steel, steel castings, &c. .\ short chapter gives a general 

 idea of the kind of tests applied to metals other than the 

 iron family. Two pages on microscopic metallography 

 are full of wisdom, counselling caution in its use alike 

 for specification and deduction, which might well be 

 taken to heart by some present day advanced workers. 

 If one remembers that the little book is of a very general 

 nature and deals with ideas about tests and testing 

 with few details, then it is heartily to be recommended. 



A. McW. . 



Karl Heumaiiu's Anleitinig sum Experimentiren hei 

 I'orlesungen iihcr anorganischen Chemie. By Dr. 

 O. Kiihling. Third edition. (Brunswick : A'ieweg 

 und Sohn, 1904.) Price 19 marks. 

 So long as the lecture system of imparting information 

 is retained, so long will the experimental demonstration 

 remain its necessary accompaniment. It is useless to 

 contend that a student cannot derive the advantage by 

 seeing an experiment performed that he would were he 

 to do it himself in the laboratory. Apart from the costli- 

 ness of much of the apparatus, the difficulties of 

 manipulation would put it beyond the power of a be- 

 ginner to obtain satisfactory results, which depend, as 

 they frequently do, on the skill and experience of the 

 experimenter. Provided an experiment is neither 

 merely pretty nor obviously sensational, nor lasts long 

 enough to interrupt the train of ideas, the effect can 



I NO. 1808, VOL. 70] 



only be stimulating to the student. But the effective 

 lecture experiment fulfilling these conditions requires 

 a good deal of thinking and working out, and that is 

 why the books on lecture experiments by Heumann and 

 Xewth are invaluable to teachers whose time outside the 

 lecture room is occupied with research or the manifold 

 duties of their departments. The third edition of 

 Heumann 's " .Anleitung zum Experimentiren " will be 

 welcomed by all teachers of chemistry. The author, 

 who is perhaps better known as the discoverer of the 

 indigo synthesis, died in 1S94, shortly after the second 

 edition of his work appeared, and the task of revision 

 has fallen to Dr. Kiihling. The experiments which he 

 has added relate to electro-chemistry, to the use of liquid 

 air in low temperature experiments, and to Moissan's 

 electric furnace and Goldschmidt"s reduction methods 

 for the production of high temperature reactions. Phy- 

 sical chemistry also claims a small share of the new 

 edition. The increasing use of the lantern has induced 

 the editor to introduce a chapter on optical projection 

 which includes an account of an electric installation for 

 the lecture room. The author has had the advantage of 

 obtaining much valuable information from such skilled 

 experimenters as Landolt, Fischer, Buchner, Bunte 

 and many others, with the result that the volume has 

 swelled to a bulk which might dismay any ordinary 

 lecture assistant. J- B. C. 



Church Strettol^. Vol. ii. Birds, by G. H. Paddock;- 

 Flowering Plants, by R. de G. Benson ; Mosses, by 

 W". P. Hamilton; Parochial History, by H. M. 

 .\uden. Pp. 205+xvii. Vol. iii. Pre-Roman,. 

 Roman, anti Saxon Archaeological Remains, by 

 E. S. Cobbold; Church Architecture, compiled by 

 E. S. Cobbold. Pp. 124 + x. Both volumes edited 

 by C. W. Campbell-Hvslop and E. S. Cobbold. 

 (Shrewsbury : L. Wilding, 1904.) Price 5s. net 

 each. 

 The first volume of this instructive guide to Church 

 Stretton, which is now complete, was reviewed in our 

 issue for October 11, 1900 (vol. Ixii. p. 571), and, as 

 pointed out on that occasion, the first instalment dealt 

 with the geology, macro-lepidoptera, and the molluscs, 

 of the neighbourhood. As might be gathered from 

 the titles of the sections into which the present two. 

 volumes are divided, the completed account of Church. 

 Stretton contains all that a visitor or resident is likely 

 to want to know. Moreover, as the volumes contain 

 the results of local scientific research and observation 

 by competent workers, they may be used with confi- 

 dence as a guide to the natural history and archaeology 

 of the district. 



In the introduction to the catalogue of the birds met 

 with in the district of Church Stretton, Mr. Paddock 

 directs attention to the fact that owing to the per- 

 sistent persecution by game preservers, some of the 

 larger Raptores, which formerly bred there, do so no> 

 longer, and that the smaller species are, from the same 

 cause, rapidly diminishing in number. .\ similar fate 

 has befallen some members of the Corvidse, though to- 

 a lesser degree. 



Mr. Benson's catalogue of the phanerogams of 

 Church .Stretton is conveniently arranged and exhaus- 

 tive in its character. Owing to the ill-health of the 

 compiler, this list was revised by Mr. Hamilton, w^ho- 

 deals also with the mosses of the neighbourhood. 



Fundamentals of Child Studv. By Edwin A. Kirk- 



patrick, B.S., M.Ph. Pp. xxi + 384. (New York: 



The Macmillan Company ; London : Macmillan and 



Co., Ltd.) Price 5*'. net. 



"This book," we are told, " is an attempt to present, 



in an organised form, an outline of the new science of 



child-study for investigators, students, teachers, and 



