5i° 



NA TURE 



[A 



PRIL 2, 1903 



The Ventilation, Heating, and Management oj 



Churches and Public Buildings. By J. \V. Thomas. 



Pp. vi+140. (London: Longmans and Co., 1903.) 



Price 2S. bd. 

 This book is addressed chiefly to the architects, mana- 

 gers and caretakers of buildings, and its opening chapter 

 deals with the physical principles bearing on ventila- 

 tion. An interesting account is given of the author's 

 observations on alternating air currents and their 

 effects. Some passages are, however, very obscure, as, 

 for instance, when one reads of " the electrical condi- 

 tions due to the sudden expansion of the air." 



In discussing the effects of wind on ventilation, in the 

 second chapter, the writer makes the cryptic statement 

 that " the friction caused by the wind passing over 

 buildings is so great that it is scarcely possible to de- 

 monstrate it accurately," and later on he speaks of the 

 air in a room as being strained " to its utmost limit 

 of tension." The next chapter is on the effects of moist 

 air on ventilation, and here the author reaches a climax. 

 In it we read of " rooms where persons are gathered 

 who evolve sputae or other germs of infectious disease," 

 and we are told that " when air is supersaturated with 

 moisture it become heavier." It is a great pity that 

 any writer should have so little sense of the responsi- 

 bility of authorship as these extracts indicate. 



The next chapter, dealing with air inlets and outlets, 

 is disfigured by an obscure passage about carbonic acid 

 being " held in suspension in a semi-dissolved condi- 

 tion " in air saturated with moisture. The actual stale 

 of the ventilation in typical buildings, and the methods 

 to be employed in order to improve matters, are next 

 treated. These portions will be found interesting and 

 suggestive. 



The remainder of the book is occupied by the discus- 

 sion of different methods of ventilation, the ventilation 

 of new buildings, and instructions for caretakers. 



J. H. V. 

 Practical Exercises in Heat. By E. S. A. Robson, 



M.Sc. Pp. xii+187. (London: Macmillan and 



Co., Ltd., 1902.) Price 24'. 6d. 

 This useful little volume contains a description of one 

 hundred and two experiments in heat, suitable for an 

 ordinary laboratory course. It is divided into fourteen 

 chapters, each of which comprises a set of classified and 

 numbered experiments — an arrangement which should 

 find favour with teachers of practical physics. At the 

 end of each chapter is given a number of additional 

 experimental exercises, mostly selected from examina- 

 tion papers of the London University. The descrip- 

 tions are clear and concise, and the text is amply illus- 

 trated; the more elaborate experimental corrections are 

 avoided, so as to allow the student to obtain a firm 

 grasp of fundamental principles. The student 

 who conscientiously works through this course 

 should gain fairly accurate results, and, what 

 is more important, a good general idea of the 

 methods of experimental research. The first two 

 chapters are devoted to measurements of tem- 

 perature, and corrections of the mercury thermometer; 

 these are followed by chapters on the expansion of solids 

 and liquids. It may be noted, in passing, that, in 

 experiment 22, p. 36, on the determination of the tem- 

 perature at which water acquires its maximum density, 

 the mercury placed in the bulb for the purpose of 

 eliminating the expansion of the latter should have a 

 volume equal to one-seventh of the internal volume of 

 the bulb, not, as is stated, one-seventh of the volume of 

 the glass composing the bulb. The expansion of gases, 

 calorimetry, and change of state are treated in miIim - 

 quent chapters. Chapters are devoted to electrical 

 methods of measuring temperature, conduction, and 

 radiation. The last chapter is occupied by experiments 



NO. 1744, VOL. 67] 



relating to elementary thermodynamics, including the 

 ratio of the specific heats of air and the value of J. 

 It may be remarked that, though a rough determina- 

 tion of J may be effected by allowing lead shot to fall a 

 number of times down a cardboard tube, and observing 

 the rise of temperature produced, yet if mercury is 

 substituted for the shot, as suggested on p. 155, no ap- 

 preciable rise of temperature will be obtained, owing 

 to the small viscosity of the mercury. In later editions, 

 it is to be hoped that an account of Prof. Callendar's 

 recently devised method of determining J will be de- 

 scribed, since this is the only satisfactory determination 

 which has so far been brought within the reach of the 

 student who can spend but a limited time over an 

 experiment. E. E. 



" The Amateur Photographer " Library. Nos. 25 and 

 26. Enlargements : their Production and Finish 

 (No. 25). By G. Rodwell Smith. Pp. xxiii + 130. 

 Price is. Bromide Printing (No. 26). By Rev. F. 

 ('. Lambert, M.A. Pp. xxiii + 74. Price 14. 

 (London : Hazell, Watson and Viney, Ltd., 1902.) 

 There is no doubt that the photographer is well 

 supplied with literature on his subject, and, as a rule, 

 he is not loth to take advantage of this source of 

 information, although he has to look about him for the 

 book containing the particular kind of help he requires. 

 There are, however, so many workers who do bromide 

 contact printing and enlarge their negatives that these 

 two small manuals on these special topics should prove 

 of great service. The authors treat each manipulation 

 separately, and explain them so that the amateur 

 can easily follow the instructions. One excellent fea- 

 ture of both these books is that the illustrations, which 

 are numerous, exhibit various types of under, correct 

 and over-exposured prints or enlargements, prints from 

 suitable and unsuitable negatives for enlarging, un- 

 touched and retouched prints, &c., which should aid 

 the beginner in forming an early judgment on his own 

 results. In addition to the actual routine of the man- 

 ipulations required,, many miscellaneous hints are 

 given, such as obtaining a bromide print quickly from 

 a wet negative, converting a bromide print into a line 

 drawing, &c. Altogether, these manuals are well 

 suited to acquaint amateurs with the nature and use of 

 the materials employed in these processes. 

 Natural Law in Terrestrial Phenomena. By Wm. 

 Digby, CLE., F.S.S., &c. Pp. xlv + 370. (London : 

 W. Hutchinson & Co., 1902.) Price 6s. 

 This book deals with the theory, revived and ampli- 

 fied by Mr. Hugh Clements, which seeks the cause of 

 all meteorological and of most volcanic phenomena 

 in luni-solar attractions. The evidence which Mr. 

 Digbv adduces in support of Mr. Clements's theory is 

 not convincing. In the early chapters, he shows how a 

 number of gales and eruptions, more particularly the 

 recent catastrophes in the West Indies, have occurred 

 at times when the astronomical conditions were favour- 

 able to the production of high tides, but the important 

 question of how often either of these two sets of phe- 

 nomena may have occurred independently of the othep 

 is not discussed. The chapters on forecasting will pro- 

 bably attract most attention. Mr. Clements tells us 

 that the earth, moon and sun occupy the same rela- 

 tive positions every 186 years, and that, therefore, 

 identical weather conditions will prevail. Given trust- 

 worthy records extending over 186 years, forecasting 

 becomes a mere matter of looking up records for cor- 

 responding days. Failing such records, we must com- 

 pare davs on which the astronomical conditions are as 

 nearly alike as possible. In appendix hi., rules are 

 given for allowing for the effect of small differences 

 in the parallax, declination and times of transit of the 

 sun and moon, on the height of the barometer, the 



