3'4 



NA TURE 



[February 5, 190^ 



" Pig iron, caustic soda, wood pulp, and scores of 

 similar articles, costing, comparatively speaking, a few 

 shillings per ton, are bought and sold on the basis of 

 strict analytical standards ; but india-rubber, costing 

 from 150/. to 500/. per ton, changes hands without either 

 buyer or seller having more than a vague knowledge of 

 its intrinsic value." 



A full description is given of the various india-rubber 

 substitutes now so frequently used, and which consist 

 either of recovered rubber from cast-off articles or of the 

 products obtained by the action of oxygen, sulphur or 

 sulphur chloride upon such substances as linseed or 

 colza oils. Inorganic compounding materials, vulcan- 

 ising agents, solvents, colouring matters and textile 

 fabrics each claim a chapter ; and, as might be expected 

 from a writer of Dr. Weber's experience and attain- 

 ments, the treatment of all these subjects is eminently 

 practical without in any degree lacking scientific 

 precision. 



Analysts and technical chemists who are called upon 

 to examine india-rubber will be grateful for the chapter 

 on the analysis of rubber articles, with which the volume 

 proper closes. Information previously scattered in 

 periodicals is here readily available, and the useful- 

 ness of the chapter is much enhanced by a section 

 dealing with the interpretation of analytical results. 

 Chemists should note that nitro-naphthalene is recom- 

 mended as a " solvent " for india-rubber in preference to 

 the nitro-benzene hitherto generally employed. 



On the whole, the author's style is lucid and his 

 English readable. Occasionally one meets with a tor- 

 tuous sentence or a quaint prepositional usage, and the 

 book generally, perhaps, lacks lightness of touch. Here 

 and there, also, a word occurs which does not exactly 

 convey the meaning intended, and rather reminds the 

 present writer of the youthful essayist who, describing 

 a storm at sea, remarked that a boy was drowned before 

 his parents' eyes, and that " it was all the more awful 

 because the father and mother were just on their honey- 

 moon." Such blemishes, however, are small matters in 

 a work of this kind. The book was wanted, and is a 

 welcome acquisition. It is written by a man who knows 

 his subject and who writes as if he loved it. The author 

 is to be congratulated upon a very useful contribution 

 to a somewhat obscure and difficult branch of technical 

 science. C. SlMMONDS. 



A BRITISH BOOK OF CONSTANTS. 

 Physico-Ckemical Tables. Vol. I. Chemical Engineering 

 and Physical Chemistry. By John Castell-Evans 

 F.C.S. Pp. xxxii -f- 548. (London : Chas. Griffin and 

 Co., Ltd.) Price 24s. net. 



THIS volume is the first half of an elaborate work 

 intended to be a compendium of tables and data 

 covering the whole domain of physical chemistry, for use 

 both in the laboratory and the works. The scheme is 

 an ambitious one, and the labour of compiling the present 

 548 pages of closely printed matter must have been no 

 light task. The book which Mr. Castell-Evans's work 

 most closely resembles is undoubtedly Landolt and 

 Bornstein's well-known treatise, which is about the only 

 one with which the writer is acquainted covering the 

 NO. 1736, VOL. 67] 



same field. The chief difference between the two books 

 lies in the fact that Mr. Evans has included about sixty 

 pages of arithmetical and algebraical data, which should 

 prove quite useful. 



The book is, on the whole, well arranged and exceed- 

 ingly comprehensive, and some of the original tables it 

 contains are among the best. The reviewer feels, how- 

 ever, that one of its chief demerits lies in the over- 

 elaboration of some matters and the very unnecessary 

 rows of figures, which many of the tables give. 



For instance, what possible significance can the last 

 two or even three figures have, when from table 47 G 

 we learn that a barometer column of 30 inches at 54° F. 

 is equivalent to 29/940213 inches at 32° F. ? or of what 

 use is it to have the equivalent of a mile in metres given 

 to fourteen significant figures when io~ 8 metre is about 

 the limit attainable in the comparison of primary 

 standards of length of the highest class ? 



Regarding the material of the work as a whole, a 

 careful perusal gives a general impression that the author 

 collected his materials and retired into his study to 

 write his book six or eight years ago, and when the book 

 came to be published overlooked the fact that our know- 

 ledge of some of the most important questions dealt 

 with has advanced very materially during this period. 

 For instance, we look in vain, under the specific heat of 

 water or mechanical equivalent of heat, for mention of 

 the work of Griffiths, of Schuster and Gannon, of 

 Callendar and Barnes, or of Reynolds and Moorby, whose 

 different researches, all published during the past few 

 years, have practically settled this question. While deal- 

 ing with this point, we notice that there occurs here in 

 the familiar form the good old text-book tradition that 

 Regnault determined the specific heat of water between 

 ordinary temperatures and 100° C. In justice to Mr. 

 Evans, however, we should mention that in his book 

 several other similar errors, which we had come to recog- 

 nise as almost always with us, are conspicuous by their 

 absence, and the book bears strong evidence that in a 

 great many cases the original authorities have been 

 consulted. 



We have verified many of the numbers, and have not 

 detected many serious errors properly so called. In 

 some cases, however, this may be due to the decided 

 superabundance of data in many of the tables (as, for 

 example, that of melting points on pp. 380, et seq). We 

 find there for the melting point of gold, 



1140°, 1200°, 1037", 1092', 1240°, 1250°, 1380°, 1100 , 1035°, 

 1045 ! most probable value 1050°; 



and for silver, 



999°, 1024°, 1000', 1032 , 916°, 1023°, 1040°, 954 , 968° : most 

 probable value 968°; 



whereas modern authorities are agreed that 1062 ± 2° is 

 a close approximation for the melting point of gold, that 

 of silver in a reducing atmosphere being very sensibly 

 ioo° lower. 



The most commendable part of the book is the sec- 

 tion dealing with vapour pressures, critical volumes, &c. ( 

 the results of the voluminous researches of Ramsay and 

 Young and other modern workers being here, with both 

 formula; and tables, given in full. 



