January 23, 1913] 



NATURE 



569 



operation. The work is an important and valuable 

 contribution to the literature of metallureiv. 



c/h. D. 



Index Zoologicus No. II. Compiled (for the 

 Zoolog-ical Society of London) by C. O. Water- 

 house and edited by David Sharp, F.R.S. 

 Pp. vi + 324. (London : Printed for the Society, 

 1912.) Price 155. 

 The subtitle of this volume describes its scope ; 

 it runs: "An alphabetical list of names of genera 

 and subgenera proposed for use in zoology as 

 recorded in the ' Zoological Record, ' vols. 38-47 

 inclusive (1901-igio), and the zoology volumes of 

 the ' International Catalogue of Scientific Litera- 

 ture,' annual issues i-io, together with other 

 names not included in previous nomenclators." 

 The first volume was published in 1902, and the 

 primary object of the present work is to serve 

 as an index to the intervening ten years, but it is 

 also planned so as to be with Scudder's " Nomen- 

 clator " a complete register of the names of genera 

 and subgenera proposed for use in zoology. The 

 editor of this volume points out that 140,000 names 

 have been, up to the present time, proposed for 

 the genera and subgenera of zoological taxonomy. 



Syst&mes Cindmatiques. By Prof. I-. Crelier. Pp. 



100. (Paris: Gauthier-Villars, 1911.) 2 francs. 



{Scientia. Janvier, 191 1. Phys.-Mathematique. 



No. 31.) 

 Under the above title, the author investigates 

 the motion of a right-angle one side of which 

 passes through a fixed point, while the vertex 

 describes a fixed right line or circle, that of a 

 rod sliding between axes at right-angles, that of 

 a crank connecting rod, and so forth ; altogether, 

 six methods of generation are investigated. The 

 curves associated with these moving systems in- 

 clude the base and rolling centrodes or loci of the 

 instantaneous centres, the envelope of the moving 

 line and those of other lines associated with it, 

 the trajectories of various points of the figure, 

 and certain envelopes of their tangents. In this 

 way a large number of curves are obtained, 

 possessing interesting properties ; of course, many 

 of these are already well known. The figures in 

 the book are rather complicated. The book con- 

 tains a portrait of Col. Mannheim and a short 

 bibliography. 



Internal Secretion and the Ductless Glands. By 

 Prof. Swale Vincent. With a preface by Prof. 

 E. A. Schafer, F.R.S. Pp. xx + 464. (London: 

 Edward Arnold, 1912.) Price 125. 6d. net. 

 Prof. Swale Vincent is well known as an inves- 

 tigator who has devoted much attention to one of 

 the most interesting chapters of physiology, 

 namely, that which deals with the group of organs, 

 formerly so mysterious, which are known as the 

 ductless glands. The adrenal bodies, the thyroid 

 and parathyroids, the thymus, the pituitary, pineal, 

 carotid, and coccygeal bodies are the principal 

 ones treated, but, as is well known, internal secre- 

 tions are also formed by glands which possess 

 ducts, and so we also have chapters on the 

 NO. 2256, VOL. 90] 



pancreas, liver, kidney, and reproductive organs. 

 The literature of the subject is enormous, and in 

 presenting a lucid and terse account of the recent 

 progress of science, and in ferreting out the 3000 

 or more references which deal with it, the author 

 has, as Prof. Schafer says in his preface, laid us 

 under a deep debt of gratitude. W. D. H. 



A Laboratory Manual of Agriculture for Second- 

 ary Schools. By Prof. L. E. Call and E. G. 

 Schafer. Pp. xv + 344. (New York: The 

 Macmillan Co. ; London : Macmillan and Co., 

 Ltd., 1912.) Price 4$. net. 



This book is issued to supply the demand that 

 has arisen for laboratory exercises in the teaching 

 of agriculture in the United States. Directly 

 agriculture becomes a school subject (and it is 

 for secondary schools that the book is intended), 

 it becomes necessary that the teacher should be 

 provided with a number of simple experiments 

 within the capacity of the scholars and of the 

 school equipment. Of course, the out-door 

 observations must still remain the essential ground- 

 work of the instruction, but a well-chosen course 

 of laboratory experiments can be arranged to 

 bring out the main principles and illustrate the 

 working of the individual factors involved. 



The lessons deal with soils, crops and animals. 

 For convenience of working they are arranged in 

 calendar form, beginning in September and con- 

 tinuing through to May, with an " extra " for Arbor 

 Day. They have actually been carried out in 

 schools, so that they are known to be workable. 



The soil experiments deal mainly with the 

 moisture relationships, which in Kansas play a 

 large and sometimes a controlling part in soil 

 fertility. The crops studied include the cereals, 

 cowpeas, cloves, lucerne and potatoes : the exer- 

 cises range over the germination, of the seed, the 

 development of the root and seed, and the ex- 

 amination of the harvest. The animal section is 

 based on the score-card method, devised in America 

 and found so useful that it has been introduced into 

 this country. 



Teachers of agriculture will find many useful 

 and suggestive lessons in the book, and it will 

 serve as an excellent example of the standard of 

 instruction aimed at in the American schools. 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.'] 



An Effect due to the Sudden Great Increase of Pressure. 



In the course of some experiments on the mapping 

 of the lines of electric force between two charged con- 

 ductors, a remarkable effect, due to the sudden very 

 ! great rise in pressure in the oil separating them, 

 occurred. The conditions of the experiment necessi- 

 I tated the use of two pointed strips of tinfoil, separated 

 1 by an interval of 1/16 in., laid on a sheet of glass 



