328 



NA TURE 



[Aug. 26, 1875 



Avogadro's law^ — the safest foundation on which to build 

 modern chemistry — is directly deducible from the funda- 

 mental equation of Clausius : — 



p^' 



■hv 



so that not only does our modern system of chemistry 

 rest on a thermodynamical basis, but the future of 

 chemical generalisation — ^judging from the tendency of 

 recent research — lies in this direction also. The subject 

 of heat has received great additions ; the laborious deter- 

 minations of the specific heats of solutions by Thomsen 

 furnish material for three pages. The " heat of chemical 

 action " has developed enormously through the labours of 

 Thomsen, Hautefeuille, Ditte, and Marignac. Berthelot 

 has also contributed largely to the subject by his thermo- 

 chemical researches. In industrial chemistry we find 

 much valuable matter added to the metallurgy of iron, 

 the article bringing us down to the invention of Siemens' 

 rotative furnace for obtaining malleable iron and steel 

 directly from the ore. In light, perhaps the most sub- 

 stantial additions to science are to be found in Glad- 

 stone's calculations of refraction equivalents, Chris- 

 tiansen, Kundt, Soret, and Sellmeier's researches on 

 anomalous dispersion, and Rammelsberg's researches on 

 the relations between circular polarisation and crystalline 

 form. The articles on the chemical action of light and 

 spectral analysis, contributed by Prof. Roscoe, are ex- 

 cellent resuims of the present state of knowledge in 

 these branches of chemical physics. In the latter subject 

 great progress has been made through the labours of 

 Lockyer (discovery of long and short lines in metallic 

 spectra), Roscoe and Schuster (new absorption spectra 

 of potassium and sodium), and Lockyer and Roberts (new 

 absorption spectra of various metals— suggestions for a 

 possible quantitative spectrum analysis). 



Prof. G. C. Foster contributes the article on magne- 

 tism, and Prof. Armstrong that <on the phenols. Most of 

 the articles on physiological chemistry are from the pen 

 of Dr. H. Newell Martin ; and Mr. R. Warington fur- 

 nishes some valuable articles on subjects relating ^to 

 agricultural chemistry. 



The second supplement exhibits all the care and pains- 

 taking conscientiousness of the former volumes, and will be 

 found of invaluable service both to teachers and workers. 

 The names of Mr. Watts and his coadjutors sufficiently 

 guarantee the reliability of the work; the " Dictionary" 

 has in fact justly taken its rank as one of the standard 

 works of reference in this country. 



Seeing that the results of chemical research are flowing 

 into the scientific world in a continuous and ever in- 

 creasing polyglot stream, both professors and students of 

 the science are indebted to Mr. Watts for the laborious 

 task which he has accomplished for their benefit 



For our own part we look with eager interest upon the 

 continuous encroachment of physics upon chemistry, and 

 venture to hope that the time may not be far distant when 

 generalisation may lead to natural classifications, causing 

 the handbooks and dictionaries of the future to be for the 

 same quantity of information somewhat less bulky in 

 volume. 



R. Meldola 



HIS ON MORPHOLOGICAL CAUSATION 



Uiisere Kdrperform und das physiolooische Problem Hirer 

 Enstehung. Briefe an einen befreundeten Naturfor- 

 scher, vonWilhelmHis. (Leipzig : Vogel, 1875. Lou- 

 don : Williams and Norgate.) 

 ''T^HIS is not, as might perhaps (from its title and from 

 J- a hasty glance at its contents) be imagined, s popular 

 exposition of the main facts of Embryology as ordinarily 

 understood. Prof. His has been led by his researches to 

 adopt peculiar views concerning the causation of animal 

 forms. These he has explained at some considerable 

 length in his great work on the " Development of the 

 Chick," and elsewhere, but they have not met with very 

 general acceptance ; and the little work we are noticing 

 has for its object a popular and somewhat fuller explana- 

 tion of these views, and a defence of them against various 

 critics. Among these critics the most conspicuous is 

 Haeckel, whose, to say the least, severe remarks on the 

 author have occasioned a very spirited retaliation. In 

 fact the work, small as it is and popular as it is intended 

 to be, is very largely controversial ; and it has always 

 appeared to us a sign of weakness when a scientific com- 

 batant brings his quarrel before a general public. 



Without going at all fully into the views of our author, 

 we may say that he strives to explain many of the facts 

 of animal morphology by the agency of mechanical causes 

 acting directly on the growing germ or embryo. Thus, 

 for him the large eyes of the young chick are the direct 

 cause, by compression, of the sharp beak of the bird ; and 

 more generally the unequal tensions produced by unequal 

 growth in the initial flat blastoderm determine, through 

 the agency of certain folds, the form of the animal which 

 springs from it. 



As might be expected, many] pages of the book are 

 devoted to an attempt at reconciling these views with a 

 modified theory of descent. Speaking broadly, the views 

 of the author may be said to differ from those generally 

 entertained, chiefly on the question whether it is the horse 

 which pulls the cart or the cart the horse, or perhaps 

 rather on the point which is the cart and which the horse. 

 We very much fear that Prof. His's horse is really the 

 cart. M. F. 



OUR BOOK SHELF 



Bristol and its Environs, Historical and Descriptive. 

 Pubhshed under the sanction of the Local Executive 

 Committee of the British Association. (London : 

 Houlston and Sons. Bristol : Wright and Co., 1875.) 



It was some time ago announced that a Guide to Bristol 

 was being prepared for visitors to the British Association 

 Meeting. This is now published, and appears as an Bvo 

 volume of 475 pages bound in cloth. In many respects 

 the local committee have made great exertions to make 

 the visit in every way a pleasant one, and this has been 

 pretty well known, but so voluminous a guide as this is 

 certainly a surprise. It is well got up, and is illustrated 

 both with views of the buildings in the town and with 

 diagrams illustrative of the geology of the district. Many 

 pens have been employed in its preparation. '• The con- 

 tributions," the Introduction states, " are honorarj — the 

 several authors have written with pure love of their sub- 

 ject, and for the sake of doing homage to the occasion 

 that has called forth the volume." 



