450 



NA TURE 



[September 6, 1894 



concise, and dealing not only with the well-known facts 

 and methods of physiological chemistry, but also with 

 the more important points of pathologico-chemical 

 interest, this work is peculiarly suited for the student 

 while going through a course of laboratory instruction. 

 From this point of view the present English version 

 should be widely welcomed. The translation has been 

 made without additions or changes from the author's 

 German edition and the original Swedish. Judged by a 

 comparison with the German, the translator must be 

 congratulated on the way he has done his work. While 

 adhering very closely and literally to the original, the 

 translation reads well and is free from the awkward and 

 often clumsy expressions which frequently result from 

 attempts to render German phrases too closely into 

 English equivalents. 



After a short introduction (chapter i.), treating in 

 a general way of some of the more important chemical 

 processes and agents which have to be dealt with in the 

 living body, the next twelve chapters give an account of 

 proteids, the animal cell, blood, chyle, lymph transuda- 

 tions and exudations, the liver, digestion, connective 

 tissues, muscle, brain and nerves, organs of generation, 

 milk, the skin and its secretions. Chapter xiv., the 

 longest and one of the most important in the book, is 

 on urine. Here, from the practical importance of the 

 subject, the treatment is more elaborate than in the 

 preceding chapters, more especially as regards details of 

 analytical methods and urinary analysis. Here also, as 

 in the other chapters, the analytico-chemical parts are 

 distinguished from the rest of the text by special type, 

 an excellent plan which facilitates the work of those who 

 may wish merely to learn what is most definitely known 

 of the substances and processes of the animal body. 

 The last chapter contains a concise but clear account of 

 the more important facts of the exchange of material 

 (Stoffwechsel) or metabolism, and of its relationship to 

 various foods and to the conditions of starvation, 

 exercise, rest,&c. Some useful tables of the composition 

 of various foods are placed at the end of this chapter, 

 and, after the index, which is full and carefully made, a 

 plate is given of the more common and important 

 absorption-spectra. 



Electricity, Electrometer, Mai^netism and Electrolysis. 

 By G. Chrystal, M.A., LL.D. and \V. N. Shaw, M.A., 

 F.R.S. (London : A. and C. Black, 1S94.) 

 The present cheap reprint of these articles from the 

 Encyclopaedia liritannica should meet with a hearty 

 welcome from all students of electricity and magnetism, 

 and more especially from those who arc desirous of 

 extending their acquaintance with the science beyond 

 the limits of ordinary elementary text-books. Such 

 students generally find a difficulty in selecting a work 

 from which to read the higher parts of the subject. 

 Maxwell's treatise is too mathematical for the majority 

 of students ; one work is, perhaps, too technical in 

 character, while another deals too exclusively with 

 practical measurements. The division of the subject 

 after the first stages into mathematical and technical 

 branches is certainly a natural one, and corresponds in 

 some measure with the requirements of students. It 

 does not, however, lighten the labours of those who ^vish 

 to obtain a grasp of general theory and experiment 

 without being cumbered with the details of machines on 

 the one h.ind, or degenerating into pure mathematics on 

 the other. For such students the articles of Prof 

 Chrystal and Mr. Shaw help to fill a gap left behind by 

 the existing text-books. The historical, experimental, 

 and mathematical portions are nicely balanced, and 

 together form an epitome of the whole subject, which is 

 made more valuable by the addition of references to 

 original papers and standard works. The student will 

 find it both a guide and a key to his reading, and by 



NO. I 297, VOL. 50] 



looking up its references he may pursue the subject to 

 any desired degree of detail. 



In the interval which has elapsed since the first 

 publication of the articles, knowledge has been accumu- 

 lated, and it is a matter for regret that the circumstances of 

 the present issue do not permit of the articles being 

 brought up to date. The absence of all reference to the 

 work of Hertz in electricity, and of Ewing in magnetism, 

 is attributable to this cause ; while Mr. Shaw's Reports 

 to the British Association show that much work has been \ 

 done, in connection with electrolysis since his article ' 

 was written. Similarly in Electro-metallurgy — an article 

 which, by the way, is not specified on the title-page 

 — considerable progress has to be reported. 



Apart from these additions, there is one point in Prof. 

 Chrystal's article which might be improved, namely, the 

 definition of the statical unit of electricity (p. 21). It 

 ought to be stated that the force exerted on the con- 

 ductors carrying the charges is measured in vacuo. 

 Indeed, it would be better to introduce the idea of specific 

 inductive capacity at this point, and so avoid a certain 

 amount of confusion between electric induction and 

 electric force in the following pages. The same remarks 

 apply to the unit of magnetism (art. " Magnetism," p. 227). 

 But although it is easy to criticise past writings in the 

 light of present knowledge, we venture to think that the 

 articles before us will stand a far more severe test than 

 many works written at a later date. 



James L. How.ard. 



LETTERS TO THE EDITOR. 



[7 he EJitor Joes not hoiJ himself responsible for opinions ex- 

 pressed by his correspondents. Neither can ht undertake 

 to return, or to correspond with the writers oj, rejectea 

 manuscripts intended for this or any other part o/NatURK. 

 No notice is taken of anonymous communications. ] 



On the Velocity of the Constantinople Earthquake- 

 Pulsations of July 10, 1894. 



According to the accounts so far published, it would appear 

 that the cpicentrum of this earthquake w.is situated under the 

 Sea of Marmora, at a short distance from San Slefano ; bul, 

 for the purpose of this paper, no very sensible error will lie 

 introduced by assuming it to coincide with Constantinople itself 



To .iscerlain the time at the origin. 1 applied to M. Coum- 

 bary, director of the Meteorological Observatory at Constan- 

 tinople, and to Mr. \V. II. Wrench, II. M. Consul. General in 

 that city. M. Coumbary informs me that the first great shock w.as 

 felt at l2h. 24m. p.m. Constantinople mean time (or loh. 28m. 

 a.m. Greenwich mean time) ; its direction was from south- 

 west to north-east, anil its d«r.ation cit;ht to ten seconds. A 

 second shock, lasting three seconds, followed immcdi.itely ; and 

 a third, of one second duration, at I2h. 31m. .\ number of 

 slight shocks succeeded these, but I have received no certain 

 record of them from distant stations. Mr. Wrench kindly 

 made inquiries of several watchmakers in the city. 

 Two regulating clocks were stopped by the principal shock, 

 oneatl2h. 20.5m., the other at I2h. 21 Jm.; both, according to 

 Iheir owners, having previously indicated correct local time. 



The earthquake was felt at liucharest, and it was also 

 registered by a horizontal |>cnilulum at Nicolaiew, and by 

 magnetic instruments at I'ola, Potsdam, Wilhclmshaven, 

 Utrecht, Pare Saint-Maur, and Kew. In the following summary 

 the times arc reduced to Greenwich mean time .^ 



Bucharest (Dr. S. C. Ilepites).— .A very sliijht shock was felt 

 at loh. 30m. I IS. a.m., of intensity 3 (Rossi Korel scale), direction 

 from cast to west. Two pendulums, (ilaced on north-south 

 walls at the Meteorological Institute, were stopped. 



Nicolaiexv (Prof. S. Kortazzi). — The curve traced by the 

 horizontal pendulum was suddenly broken at loh. 30m. 36s. 

 a.m. ; the pendulum itself was thrown out of position, and was 

 found afterwards leaning against one of the side supports. 



I'ola (Dr. S. Miiller).— I'he declination curve shows two dis- 

 turbances, at loh. 36m. 37s. and loh. 41m. 37s. a.m. The 

 movements indicated on the bifilar an 1 Lloyd's l)alancc curves 

 are very slight. 



