Jan. 4, 1 872 J 



NATURE 



179 



similar design to one made by tlie same artist for tlie 

 Wilna Observatory, which lias produced sun-pictures that, 

 so far as the eye can judge, leave nothing to be desired 

 in point of sharpness of definition and freedom from 

 such distortion as the photographed cross- wires can ex- 

 hibit. The object-glasses will be of about 4in. diameter, 

 giving focal images of the sun about half an inch in. 

 diameter. The focal image will be amplified to about 4in 

 diameter on the photographic plate, and, in applying the 

 ■ enlarging lens, Mr. Dallmeyer is confident that he can 

 entirely destroy the spherical aberration. The camera- 

 telescopes will be mounted on equatorial stands, with 

 latitude adjustment of 80° range ; and they will be fur- 

 nished with driving clocks.* 



For the general photographic organisation, the Astro- 

 nomer Royal has secured the co-operation of Mr. De La 

 Rue, under whose able supervision the instruments above 

 mentioned will be constructed, and by whom the various 

 details of the photographic scheme will doubtless be 

 arranged. Of the five stations already selected for eye 

 observation of contacts, three are well suited for photogra- 

 phic record. These are Rodriguez, Kerguelen's, and Auck- 

 land, at all of which the whole transit will be visible. The 

 Hawaiian station and Alexandria, though they are avail- 

 able, are less advantageous than the rest, because only a 

 portion (about half) of the transit will be visible from 

 each, and the photographs, besides bemg thus limited) 

 must be obtained at low altitudes of the sun. It may 

 become a question whether the heliographs provided with 

 a view to furnishing these two stations cannot be more 

 advantageously located. But before the positions are 

 finally decided upon, it appears desirable that the inten- 

 tions of other nations should be fully known, or, as would 

 be preferable, that the ultimate distribution of observers 

 of all kinds — telescopic, heliometric, and photographic — 

 should be made the subject of an International Con- 

 ference. J. Carpenter 



JUKES' S MANUAL OF GEOLOGY 



The Sliidenfs Manual of Geology. By J. Beete Jukes 

 F.R..S. Third edition, re-cast, and in great part re- 

 written. Edited by Archibald Geikie, F.R.S. (Edin- 

 burgh : A. and C. Black, 1872.) 



IF there be any one feature more strongly marked in 

 the present age than another indicative of progress 

 and intellectual advancement, it is the superiority of most 

 (we will not say of all) of the books intended to promote 

 education. School books and class books of all kinds, 

 instead of being merely reprints, as in the days of yore, 

 now really undergo revision every five years or so, or are 

 superseded by new ones ; whilst the introduction of 

 natural science teaching into our Universities and public 

 schools has created a demand for te,\t-books to an extent 

 greater even than the supply. 



Among the various writers of the day on the science of 

 Geology, Sir Charles Lyell must undoubtedly be placed in 

 the front rank, as having done more than any other man 



' There .ire grounds for Iioping that the same artist will construct 'iome 

 precisely similar photo-heliographs for other countries, for use on the Venus 

 Transit. There would manifVstly be great advantage in the employment by 

 all photographing observers of instruments whose optical portions at least are 

 of identical material and manufacture. 



to promote its study, and his " Principles" and " Elements" 

 of Geology still hold tlie highest places in cur estimation ; 

 but we must not forget that Phillips, Dana, and Jukes 

 have also furnished us with geological manuals, more 

 elementary in their style and arrangement, and therefore 

 more serviceable for beginners than are Lyell's works. In 

 order, however, to remedy this, Sir Charles Lyell has 

 lately brought out a " Student's Elements of Geology," 

 Svo. pp. 624 (Murray), being an abridged edition of his 

 larger work. This will no doubt prove a very useful 

 book to beginners as an introduction to the higher class 

 books. 



Jukes's ".Student's Manual of Geology" was born in 

 1857, and has already gone through two previous editions, 

 each time, as is the sad fate of such books, growing more 

 corpulent, till the poor student turns pale before the vast 

 array of facts, neatly arranged for him to "cram," in the 

 smallest possible type. 



The original design contemplated in 1S54 was an 

 article on Geology for the " Encyclop;cdia Britannica," to 

 have been carried out by the late Prof. Edward Forbes 

 and Mr. J. Beete Jukes conjointly ; but the death of 

 Forbes for a time deferred the task. It was afterwards 

 inserted in the Encyclop;edia under " M," as " Minera- 

 logical Science," and finally appeared as a separate work 

 in 1S57. The first edition is comprised in 610 pp., and 

 is illustrated by 7.1. woodcuts, chiefly diagrams and sec- 

 tions of rocks, &c. 



The second edition appeared in 1862, having grown an 

 inch in the size of its page, and added 154 pages to its 

 bulk, partly owing to the addition of 100 more illustrations, 

 50 of which are of fossils, or rather groups of fossils. 



The idea of these figures of " Fossil groups," as they 

 are termed, seems to have been taken from the admirable 

 series of little woodcuts which illustrate the invertebrate 

 portion of Owen's " Pahrontology,'* prepared by the late 

 Dr. S. P. Woodward. They are, however, arranged 

 stratigraphically in Jukes's " Manual," not zoologically, as 

 in Owen's " Paleontology." 



The third edition, now before us, is only fourteen pages 

 thicker than the second edition, and contains thirty-one 

 more illustrations ; but the bulk of matter is vastly in- 

 creased by the use of smaller type than in the former edi- 

 tions. 



The illness which seized Mr. Jukes, and by which 

 he was removed from among us, had already impaired his 

 health so much as to render it desirable he should be 

 relieved of the labour of completing this edition, and the 

 task was accordingly, by the author's own wish, undertaken 

 by Professor Geikie, Director of the Geological Survey of 

 Scotland. 



The eighty pages on mineralogy I forming chapters II. 

 and III.) have been entirely re-written by Dr. Sullivan; 

 Chapter XI 1 1,, on trap-rocks, has been re- written by Prof. 

 Geikie, as well as many other parts. Mr. Hull has rexised 

 the description of the English Coal-measures. Messrs. 

 Bristow, Whitaker, and Judd have looked over the Meso- 

 zoic and Cainozoic chapters, and Prof. Huxley has con- 

 tributed a new synopsis of the animal kingdom. 



By a modification of the former edition, a new part is 

 introduced (Part II,) called "Geological .'Agencies, or 

 Dynamical Geology," a part of which also is from the pen 



* Second Edition, i86i (Edinburgh : A. and C. Black). 



