422 



NATURE 



[June 26, 19 13 



is probably psychologically sound. There are also 

 chapters on graphical consl ructions, on plan and 

 elevation, and on contour lines. The work con- 

 cludes with a section on kinematics. A good set 

 of graduated examples, together with numerical 

 tahles and formulae, will be found at the end. 



(2) M. Guillet's book on vibrations is of the 

 nature of a monograph in which the mathematics 

 of "small oscillations" have been collected and 

 classified, with numerous illustrations taken from 

 the theories of light, sound, and electromagnetism. 



The whole is a reprint from notes taken by Dr. 

 M. M. Aubert of lectures given in the University 

 of Paris by the author. The first part of the 

 book deals with the theory of simple harmonic 

 motion, free and damped. Several chapters are 

 devoted to the composition of such motions, of 

 plane and elliptically-polarised vibrations, and to 

 phenomena of interference. A number of examples 

 of the calculation of differences of path are given, 

 having special reference to well-known problems 

 of diffraction. 



The second part deals with the propagation of 

 waves in elastic solids and fluids. The author 

 establishes the equations of equilibrium and small 

 motion of an elastic solid, and deduces solutions 

 of the problems of flexure and torsion in the sim- 

 plest cases. He considers the propagation of 

 dilatational and distortional waves in elastic media, 

 and also the vibrations of rods and wires. 



The book concludes with a consideration of the 

 elastic-solid theory of the luminiferous aether, the 

 elastic constants being adjusted to give Lord 

 Kelvin's well-known "contractile " aether ; certain 

 vectors found are then interpreted in terms of the 

 electromagnetic theory. 



A work of this nature, which touches upon 

 a number of different theories, is always liable to 

 fall into the defect of " scrappiness," and it can- 

 not be said that the present volume altogether 

 escapes this reproach ; it is, however, both in- 

 structive and stimulating, and contains a great 

 deal of valuable information — information which 

 is usually widely scattered, and therefore largely 

 unavailable for the learner. In this sense the 

 book supplies a distinct want. L. N. G. F. 



OUR BOOKSHELF. 



Abhandlungen mid Vortrage zur Geschichte der 



Natur-wissenschaften. By Prof. E. O. von 



Lippmann. Zweiter Band. Pp. x + 491. 



(Leipzig: Veit and Co., 1913.) Price 8 marks. 



Prof, von Lippmann presents in this volume a 



second collection of the valuable historical studies 



which he has contributed to Chemiker-Zeitung 



and other periodicals. The articles are thirty-six 



in number, and, like those published in the former 



NO. 2 2T8. VOL. Oil 



volume, range over the whole history of chemistry. 

 They exhibit the author as a man of wonderfully 

 wide learning and remarkable security of scholar- 

 ship. 



The studies are divided into eight sections upon 

 a chronological basis. The first section contains 

 an analysis, from the point of view of chemical 

 knowledge, of the famous medical papyrus, of the 

 sixteenth centry B.C., discovered by Ebers at 

 Luxor. A second article, on the term "caput 

 mortuum " ( = iron oxide), throws interesting light 

 upon the mystical interpretations of chemical 

 phenomena which originated, like the "black art" 

 itself, in Egypt. The second section deals with 

 Greek and Hellenistic chemistry. Here, as is 

 fitting, Plato and Aristotle have the pride of place, 

 the great achievements of Aristotle receiving par- 

 ticularly careful attention. A short note upon 

 Archimedes 's method of determining specific 

 gravity Leaves the "eureka" story unassailed in 

 principle, but proves that the "crown" of Hiero 

 was really a golden wreath. On the other hand, 

 the author robs that early precursor of Mme. 

 Curie, the alchemist Maria (possibly of the first 

 century A.n.), of the credit of inventing the water- 

 bath ("balneum Maria;") and Papin of his 

 "digester," showing that the former was known 

 before Aristotle and the latter in the third century 

 a.d. These two destructive articles illustrate very 

 well Prof, von Lippmann 's encyclopaedic know- 

 ledge of the literature of his subject. Among the 

 most interesting of the later articles are those on 

 the chemical names used by Marco Polo, on J. J. 

 Becher's observations anticipatory of Mendel and 

 De Vries, on Jean Re}', on the word "gas," which 

 van Helmont is declared to have adopted from 

 the "chaos" of Paracelsus, and on E. C. Howard, 

 the inventor of the vacuum apparatus for sugar- 

 refining. But the author has touched no subject 

 which he has not adorned. 



Mineral and Aerated Waters. By C. Ainsworth 

 Mitchell. Pp. xiii + 227. (London: Constable 

 and Co., Ltd., 191 3. ) Price 8s. 6d. net. 

 The author takes us back to the beginnings of 

 the mineral-water industry by interesting descrip- 

 tions of natural mineral springs, spas, and holy 

 wells ; for it was from the first attempts to copy 

 the actual or supposed healing virtues of such 

 waters that the extensive manufacture of mineral 

 waters began, developed, and expanded into the 

 great industry of to-day. The analyses of the 

 more famous natural waters are given in the first 

 part of the volume, devoted to the history of the 

 subject, and perhaps the most striking feature 

 of this history is the changed aspect of current 

 belief in the efficacy of such waters by the known 

 presence of radio-active substances contained in 

 some of them. The chemical constituents being- 

 accurately known, a natural water can be pro- 

 duced in the laboratory, but, as is frequently 

 asserted, without the therapeutic action of the 

 natural product. The author states, however, 

 that "recently bottles of special construction, con- 

 taining artificial radio-active mineral waters, have 

 been put upon the market in Sweden." 



