36 



NA TURE 



[July 8, 1922 



The elementary principles receive full treatment, 

 nearly fifty pages being devoted to their consideration. 

 After a description of the properties of X-rays and the 

 peculiarities of X-ray tubes, the production of high- 

 tension currents is treated. The remaining chapters 

 are devoted to the various parts of an X-ray installa- 

 tion, the actual taking of skiagrams, and the localisation 

 of foreign bodies. 



The description given to Fig. 25 will no doubt be 

 altered in a future edition and the X-ray tube depicted 

 in Fig. 26 be given terminals of different signs. Though 

 written by a physicist, it is evident that the writer 

 has had some practical experience in the radiography 

 of the human subject, which enhances the value of 

 the book. 



The Principles of Mechanical Refrigeration. (A Study 

 Course for Operating Engineers.)- By Prof. H. J. 

 Maclntire. Pp. viii + 252. (New York and London : 

 McGraw-Hill Book Co., Inc., 1922.) 125-. 6d. 



The engineering courses at our Universities and 

 Technical Schools deal as a rule much more thoroughly 

 with the conversion of heat into work than with 

 the conversion of work into heat, or rather, into the 

 absence of heat. This holds to a considerable extent 

 for American universities and colleges, and it is for 

 engineers so trained that the present volume is intended. 

 Attention is directed chiefly to the details in which 

 refrigerating machinery differs from the machinery 

 with which the average engineer is familiar. It is 

 probably due to the simplicity of the new problems 

 which the ammonia refrigerating plant brings before 

 the mechanical engineer that ammonia owes its popu- 

 larity. The actual cost of producing a given amount 

 of refrigeration is almost the same by the three or four 

 methods at present in use, and the author of the present 

 work thinks that the carbonic acid has many advan- 

 tages over the ammonia method. Ethyl chloride used 

 with a rotary compressor is extensively used in the 

 American Marine, and much more information on the 

 use of this material would be welcomed by refrigerating 

 engineers in this country. The book contains tables 

 of the properties of refrigerants compiled from Bureau 

 of Standards reports, which are more up-to-date than 

 any with which we are acquainted in books published 

 in this country. 



The Stagery of Shakespeare. By R. Crompton Rhodes. 

 Pp. xii + 102. (Birmingham: Cornish Bros., Ltd., 

 1922.) 4s. 6d. net. 



Mr. Rhodes's little book is an important contribution 

 to the study of the stage-craft of Shakespeare and his 

 contemporaries. His method has been to compare 

 closely the stage directions of the quarto editions of 

 the plays and those of the First Folio. He finds that 

 in the quartos which are generally recognised as 

 pirated, the stage directions have the character of 

 observations rather than of instructions, as mighl be 

 expected from the circumstances of their origin. As 

 a result of the comparison, Mr. Rhodes is able to offer 

 a number of suggestions as to the use of the curtains to 

 provide a recess on the stage and the use of the balcony 

 covering the three terms used by Shakespeare. " aloft," 

 "above," and "at a window." His deduction that 



NO. 2749, VOL. I io] 



in those cases in the First Folio, where there are no 

 stage directions or very few — " The Two Gentlemen 

 of Verona," " The Merry Wives of Windsor," " Measure 

 for Measure," " The Winter's Tale," and " King John," 

 ' — we are dealing with a text assembled from the 

 players' parts, deserves attention in the consideration 

 of a difficult problem, for the solution of which Sir 

 Sydney Lee's theory of transcripts in private hands 

 does not appear entirely convincing. 



Twenty-Five Years in East Africa. By Rev. John 

 Roscoe. Pp. xvi + 288 + xix Plates. (Cambridge: 

 At the University Press, 1921.) 255. net. 



In this volume, Mr. Roscoe has given an account of 

 some of his experiences and observations of the manners 

 and customs of the natives of East Africa during his 

 twenty-five years' service as a missionary in that area. 

 In particular his aim has been to describe the con- 

 dition of the country and the natives when first he 

 took up his work. From this point of view, his book 

 forms a useful pendant to the more strictly ethno- 

 graphical works he has already published dealing with 

 the Baganda and other Bantu tribes. The connected 

 narrative adds colour to these analytical studies. When 

 Mr. Roscoe first arrived in the country the Uganda rail- 

 way, of course, was not in existence, and he gives a vivid 

 picture of the difficulties encountered by the traveller, 

 arising both from the character of the country and the 

 untrustworthiness of the native carrier, the only means 

 of transport. To many of his readers the most in- 

 teresting section of the book will be that dealing with 

 the events, of which he was an eye-witness, leading 

 to our assumption of the Protectorate over Uganda. 

 In this account, curiously enough, Sir Frederick Lugard 

 is mentioned only incidentally. 



Joseph Glanvill and Psychical Research in the Seven- 

 teenth Century. By H. Stanley Redgrave and I. M. L. 

 Redgrove. Pp. 94. (London : William Rider and 

 Son, Ltd., 1 92 1.) 2S. 6d. net. 



Joseph Glanvill is no doubt best known to the 

 modern reader as the source of inspiration of Matthew 

 Arnold's well-known poem, and secondly as author of 

 a treatise on witchcraft which W. E. H. Lecky de- 

 scribed as " probably the ablest book ever published 

 in defence of the superstition." It is not so generally 

 known that Glanvill was an ardent advocate of the 

 experimental method and a sturdy opponent of dog- 

 matism. He was not only a Fellow of the Royal 

 Society, being elected in 1664, and a friend and admirer 

 of Robert Boyle, but in addition to making three com- 

 munications to the society which appeared in the 

 Transactions, he was the author of an account of the 

 advances in the various departments of scientific know- 

 ledge since the time of the ancients. Incidentally in 

 this work he suggested that the Torricellian vacuum 

 was not an absolute void. In the short account of 

 Glanvill under notice his various activities are noted 

 and his views set forth, for the most part, in his own 

 words. The authors are, however, chiefly interested 

 in his psychic investigations, on account of which he 

 may be considered, legitimately, to be the founder of 

 modern psychical research. 



