Feb. 4, 1 8 75 J 



NATURE 



267 



by far the most important commercially ; nevertheless, 

 we could have wished to find brief accounts of such metals 

 as manganese, magnesium, cadmium, palladium, potas- 

 sium, and sodium. 



We have already referred to the excellence of certain 

 drawings, and it is only necessary to add that throughout 

 the volume the illustrations are of very high merit. They 

 are evidently drawn from actual measurement, but it is 

 to be regretted that scales are not given. 



The author states in his preface that the object which 

 he had in view was " to supply, within moderate limits, 

 such practical information on general principles, and 

 typical processes, as may not only afford a comprehen- 

 sive view of the subject, but also enable the reader to 

 study with advantage more elaborate treatises and ori- 

 ginal memoirs." Certainly this object has been attained ; 

 and we think he has done more, in that he has produced 

 a work which not only fully sustains his reputation, but 

 affords fresh evidence of his having done much scientific 

 work of a kind far too rare in this country. 



OUR BOOK SHELF 



Dciccndcn::lehrc iind Darwinisviiis. Von Oscar Schmidt. 



(Leipzig : Brockhaus, 1873.) 

 This volume of three hundred pages is one of the " Inter- 

 national Scientific Library." It is a moderate exposition 

 of the Darwinian theory of Evolution, intended for general 

 readers, and while free from the eccentricities of H;cckel's 

 Anlhropogenie, also lacks the brilliancy and power which 

 redeem its faults. Prof. Schmidt while sliU at Gratz 

 became a convert to " the new philosophy," and in his 

 ViTi^lciihendc A>!d/(>//!u- {Natvre, vol. v. p. 228) adopted 

 its conclusions as the basis of his teachirjg. In a paper 

 read before the " British Association " of Germany two 

 years ago, at "Wiesbaden, he stated and defended his 

 change of opinion, and now that he is established as pro- 

 fessor in Strassburg University, he puts forward this 

 volume as a fuller exposition of his views — " for here one 

 must show one's colours." It is perhaps undesirable for 

 people to attempt arriving at the results of science by 

 such easy roads as popular treatises, and " The Descent 

 of Man " itself is abetter interpretation of Darwinism than 

 the expository treatises of Darwinists ; but there is un- 

 doubtedly a demand for books of this kind, and if they 

 are to be written, it is well that so competent a hand as 

 Prof. Oscar Schmidt's should do it. There are several 

 woodcuts, a good list of references, and the inevitable 

 genealogical trees. 



We also note the appearance of an essay attacking the 

 theory of Evolution, by Prof. Wigand, of Marburg ; and 

 a reply to it by Prof. Jager, of Stuttgart. The former, 

 entitled DarwiHisiniis und die Naturforscliuns^ Newloii's 

 und Cuvicis, is a temperate production, written from the 

 point of view of a botanist. The latter is a more lively 

 rejoinder, and appears as In Saclicn Darwin's insbc- 

 sondere contra Wigand. P. S. 



The Micrographic Dictionary : a Guide to the Exa- 

 mination and Investigation of the Structure and 

 A'ature of Microscopic Objects. By J. W. Griffith, 

 M .D., and A. Henfrey. Third Edition, edited by J. W. 

 Griffith and Prof. M. Duncan, assisted by the Rev. M. 

 J. Berkeley and T. Rupert Jones. (London : J. Van 

 Voorst, 1S75.) 

 We have from time to time chronicled the progress of 

 this work, and have now the satisfaction of announcing 

 its completion. In a work of this kind, which has been 

 upwards of three years in passing through the press, it is 

 inevitable that minute criticism should detect some 



discrepancies between the various articles, and some 

 passages in the earlier pages which would not have been 

 written in the light of more recent investigations. It is 

 probable, also, that workers in different fields will place 

 a different estimate on the importance of their own 

 department, and will be disposed to grudge the space 

 devoted to others. The student of Cryptogamic Botany 

 has at all events the lion's share, almost every genus in 

 some groups being described. In the present chaotic 

 state of the classification of Cellular Cryptogams, it is 

 probable that a number of the genera and even groups 

 treated of in this work as autonomic will have ultimately 

 to be abandoned. There is, however, so much that is of 

 the greatest value to every microscopist, that we can 

 cordially recommend the work as indispensable to the 

 student. The plates, some of which are new, and others 

 re-drawn, are of themseU'es of great and permanent 

 value. 



Temperature Chart of the United States, showing the 

 Distribution by Isothermal Lines of the Mean Tem- 

 perature of the Year. Constructed under the direction 

 of Prof. J. Henry, Secretary, Smithsonian Institution, 

 by Charles A. Schott, Assistant U.S. Coast Surrey, in 

 October 1872. 

 This temperature chart, which by the way should have been 

 accompanied with some explanatory remarks, has been 

 issued by the Smithsonian Institution. The isothermals 

 are given for every 4° P., beginning with 36° in Minnesota 

 and the northern shores of Lake Superior, and rising suc- 

 cessively to 76 ' in the extreme south of Florida. The 

 lines have evidently been drawn from mean annual tem- 

 peratures, uncorrected for height, and are therefore 

 designed to show the actual distribution of mean annual 

 temperature over the surface of the United States. This 

 method of representing the distribution of temperature, 

 which has been employed by Petermann and others, is 

 well suited for various purposes for countries, such as 

 Russia, which consist chiefly of extensive rolling plains ; 

 but it is not suited for Scotland, Switzerland, and other 

 mountainous regions. In the mountainous parts of Great 

 Britain, for instance, isothermals so drawn, had we the 

 data to do it, would be neither more nor less than contour 

 lines. The fault of the chart consists in not keeping this 

 distinction in view. Thus, in the Rocky Mountains, the 

 isothermal of 44'' passes over Denver, the mean tempera- 

 ture of which, on an average of three years, is 5i°'o; 

 and in the Alleghany Mountains, Ashville, N.C., lies 

 within the closed isothermal of 48", but its mean tempera- 

 ture on an average of four years is 54°. In constructing 

 such charts, mountainous regions should be altogether 

 kept clear of the isothermals. For the vast plains of the 

 States the chart is a valuable one, and the tracing of 

 the influence of the lakes, river basins, and more marked 

 contour lines on the course of the isothermals, is very 

 instructive. After a somewhat minute examination of 

 the lines, we have only to note, in way of criticism, that 

 the isothermal of 44° is drawn too far northward in the 

 region of Lake Ontario ; the mean temperature of Toronto 

 being 44°'2 and Kingston 42"'8, showing that it should be 

 drawn nearly along the northern shore of that lake. 



LETTERS TO THE EDITOR 



[ Till Editor does not hold hhnself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the -uriters of, rejected manuscripts. 

 No notice is taken of anony!?ious communications.^ 



Sub-Wealden Exploration 

 It must be with great regret that geologists see the announce- 

 ment made in Nature, vol. xi. p. 236, that all the efforts to 

 clear the bore-hole at Neiherfield have been unavailing, and that 

 it has to be abandoned. But is it advisable, I would ask, that 

 another should be commenced on the same spot? When the 



