690 



NATURE 



[February 26, 1920 





would still have left those whom he addresses with 

 the impression that they are studying, not the 

 sifted wisdom of the ages, but the opinions of 

 M. Maurice Lecat. 



However, the subsidiary claim that he makes 

 may be heartily supported. It is a most entertain- 

 ing volume to dip into for a few moments to pass 

 the time. If it were only rather handier, and the 

 type a little larger, it would be ideal for the bed- 

 side. As it is, perhaps the dentist's waiting-room 

 provides for it the proper sphere of usefulness. 



N. R. C. 



OVR BOOKSHELF. 

 Penrose's Annual. Vol. xxii. of "The Process 



Year Book." Edited by William Gamble. 



Pp. X-)- 1 12-)- plates. (London: Percy Lund, 



Humphries, and Co., Ltd., 1920.) Price 



los. 6d. net. 

 Our special congratulations are due to the editor 

 and publishers of this ever-welcome annual that, 

 after an interval of three years, they have been 

 able to resume its issue. The editor, as usual, in 

 his " Foreword " reviews the recent advances and 

 the present condition of the reproductive graphic 

 arts. In the circumstances one could scarcely 

 expect anything strikingly new, but we are told 

 that one bright and hopeful feature of the present 

 is that work is now being adequately paid for, and 

 that as a consequence employers are able to give 

 satisfying wages as well as to improve their plants. 

 Photo-lithography is coming more and more into 

 use. Collotype is "coming into its own again, 

 thanks to the absence of German competition." 

 The collotype work now being done in this country 

 is of excellent quality, and probably greater in 

 quantity than ever before. Half-tone and three- 

 colour work stand pretty much where they were 

 before the war, while rotary photogravure is 

 coming increasingly to the front for newspaper 

 and periodical work. It is now quite practicable 

 to print both text and illustrations together by this 

 last process, and there are signs that before very 

 long type-setting may be rendered unnecessary. 

 Two American journals have already been pro- 

 duced without the aid of the compositor. The 

 volume contains articles from the pens of many 

 contributors, and is very rich in illustrations of all 

 kinds. C. J. 



The Occlusion of Gases by Metals : A General 

 Discussion held by the Faraday Society, 

 November, 1918. (Reprinted from the Trans- 

 actions of the Faraday Society, vol. xiv., parts 

 2 and 3, 1919.) Pp. 93- (London : The Fara- 

 day Society, n.d.) Price 8s. 6d. 

 This volume contains a record of another of the 

 valuable symposia held by the Faraday Society. 

 The subject of the gases retained by solid metals 

 bears on a number of technical processes, so that 

 the papers contributed cover a wide range. Sir 

 Robert Hadfield's introduction gives a useful sum- 

 mary of the knowledge of the gases in iron and 

 NO. 2626, VOL. 104] 



steel, with a bibliography. The theoretical aspects 

 are dealt with by Profs. Porter and McBain, the 

 well-known case of the absorption of hydrogen 

 by palladium receiving attention, whilst Dr. 

 McCance's paper on balanced reactions in steel 

 manufacture discusses the question of the equi- 

 libria in the steel furnace which determine the 

 proportions of the various gases which will be 

 in contact with the metal at the time of tapping. 

 The view that the amorphous phas6 in solid 

 metals is responsible for much of the dissolved 

 gas is maintained by several of the contributors, 

 but no evidence is adduced to prove that gases 

 are insoluble in crystals of pure metals. The 

 fact that the solubility of gases in molten metals 

 increases with the temperature has often seemed 

 remarkable, but Prof. Wilsmore points out that 

 this is probably the normal behaviour, water being 

 exceptional in its diminished solvent power for 

 gases with increasing temperature. The discus- 

 sion contains much that is of interest both to 

 metallurgists and to physical chemists. 



C. H. D. 



Examples in Heat and Heat Engines. By T. 

 Peel. Pp. iii+104. (Cambridge: At the Uni- 

 versity Press, 1919.) Price 55. net. 

 The working of exercises forms a very important 

 part of the course work of an engineering student. 

 Many of the exercises required for the purpose 

 of elucidating the subject of heat and heat engines 

 can easily be made up; on the other hand, there 

 ■are many important facts which can be illus- 

 trated only by exercises containing as data observa- 

 tions made during experiments. Teachers and 

 students will welcome the book before us, because, 

 among numerous other exercises, there is a large ^1 

 number giving experimental data on steam, g^s^j^H 

 and oil engines, steam boilers and turbines, re- ^Bj 

 frigerators, and calorimetric work. It is true that 

 the best data for exercise working are those 

 obtained by the student in experiments carried out 

 by himself. Since most heat and heat-engine tests 

 take a rather long time to carry out, the amount 

 of information thus accumulated in the case of any 



one student can have only a limited scope, and , 



the excellent exercises contained in the book wilU^^ 

 make a very useful supplement. i^l 



The Hill of Vision : A Forecast of the Great War 

 and of Social Revolution with the Coming of 

 the New Race. Gathered from Automatic 

 Writings obtained between 1909 and 1912, and 

 also, in 1918, through the Hand of John Alleyne 

 under the Supervision of the Author. By 

 Frederick Bligh Bond. Pp. xxv+134. (Lon- 

 don : Constable and Co., 1919.) Price 75. 6d. 

 net. 

 This book is a sequel to "The Gate of Remem- 

 brance," which contained an account of the auto- 

 matic script giving instructions for excavations in 

 Glastonbury. The further script now published 

 deals with the war and after, but it cannot be 

 said that the correspondences and verifications 

 of predictions pointed out are particularly striking 

 or convincing. 



