June 1, 1899.] 



KNOWLEDGE. 



135 



varied contents, by means of descriptions given by eye witnesses, 

 and makes us realize the gigantic forces that must be at work to 

 produce so magnificent a result. He takes us into the laboratory 

 and examines and classifies for us the dust and fragments of the 

 sedimentary or metamorphic or crystalhne rocks that have been 

 ejected from the open fissures. The stalactites of lava and the 

 columnar or basaltic joining that are here and there mot with 

 are passed under review before the author conducts us into that 

 instructive theatre of extinct volcanoes which the district of 

 Auvergne has preserved for our study and delight. A chapter 

 is given on the history of British volcanoes, the author drawing 

 from and recognizing the admirable treasury of information 

 compiled by Sir A. Geikie. It might seem that the number of 

 facts collected and discussed would be sufficient to afford a 

 complete theory of vulcanicity. Professor Bonney, however, 

 regrets his inability to put forward any completely satisfactory 

 hypothesis. Either .some links in the chain of evidence still 

 remain to be discovered, or the relations of those which we know 

 have not yet been fully understood. We can afRrm a fact more 

 easily than we can offer an explanation. Admitting that a volcanic 

 eruption is due to the upheaval of more or less e.xplosive material 

 at a high temperature, there still remains to be answered the 

 apparently simple question — What causes the high temperature V 

 Some may think that this question admits of an easy answer, but 

 Prof. Bonney considers both the mechanical and the chemical 

 theories that have been advanced, and finds both deficient. 



Lahoratori/ Manual oii Astronomy. By Mary E. Byrd, n.A. 

 1899. (Ginii & Co., Boston, U.S.A.) The astronomy of to-day 

 may be said to have specialized itself into two distinct forms. 

 There is the astronomy of theory and of mathematics, and there 

 is the practical astronomy of observation. Both are good in their 

 kind ; but it is to the former that the attention of our schools and 

 colleges is almost exclusively directed, though it must be admitted 

 that the latter is much more potent as a means of training and 

 develo])ing the iutellect. It has always been a.ssumed that large 

 and complicated instruments are necessary for the practical 

 working of astronomy, and, as a matter of fact, it is much less 

 trouble to confine oneself to text-books. Miss Byrd's book, 

 therefore, forms quite a new departure in astronomical manuals, 

 and as a guide to the training of beginners in the actual, 

 practical, out-of-door, study of the science, it deserves the 

 highest praise. Apart from the intrinsic value of the manual, 

 Miss Byrd's book will do good service if it persuades our 

 teachers that the study of astronomy should begin with naked- 

 eye observation, and that complicated and well-finished in- 

 struments are a hindrance rather than a help to the training 

 of the beginner, where he or she could otherwise be induced 

 to make the elemental instrument necessary to the observation. 

 Though " no inroad has been made into the province of the 

 regular text-book,'' there are two appendices which we would 

 recommend to the study of observers. The first is by a leading 

 authority — Prof. Arthur Searle — on " The Zodiacal Light,'' and 

 the second on "Moonrise," by Prof. E. Frisby. We think that 

 the students of Smith College are much to be congratulated in 

 the possession of such an instructor and director of the observa- 

 tory as we would judge Miss Byrd to be. 



Photo-ificrograjtluj. By Edmund J. Spitta, L.R.f.p., m.r.c.s., 

 F.R.A.S. (The Scientific Press.) r2s. This is one of the best 

 books on photo-micrography that has yet come before our 

 notice. Most of the volumes on the .subject that have been 

 issued of late years are little better than treatises on the 

 technique of photographic processes, with an occasional chapter 

 on photo-micrography culled from papers already published in 

 the proceedings of the Microscopical and other societies. We 

 are therefore glad to welcome a work like this, which devotes 

 itself to its subject, and which is, at once, both original and 

 practical. Every page ofliers evidence of extensive knowledge 

 of minute detail and wide research, such as could only be shown 

 by one who had a practical acquaintance with the difficulties 

 that are to be met with in laboratory practice. The author 

 treats of his subject under four heads, viz., illuminants, low 

 power work, medium power work, and high power or critical 

 work. The book, as a whole, is so good and so admirably 

 arranged that one regrets to see that occasion is offered for 

 criticism of any kind. The question of illuminants, which is 

 treated of in Chapter I., does not, however, receive that 

 attention that it merits. To dismiss so important a ])art of the 

 subject with a brief dissertation of nine pages is, in our opinion, 



a defect which the author would do well to attend to in future 

 editions. One result is that much has been omitted that might 

 have been included with advantage. For example, magnesium 

 ribbon, and the use of minute platinum wire loops with a 

 Bunsen flame, rank among the best illuminants that the operator 

 can use for low power and for medium power work. The 

 author evidently has a jxnclianf for lime-light, and, therefore, 

 all other illuminants that do not, in his opinion, lend themselves 

 for critical high power manipulations (a class of work which the 

 majority of students have neither the means nor the oppor- 

 tunities of practising) are either accorded but scant attention 

 or are ignored. Four chapters are devoted to the technique of 

 low, medium, and high power work, ami it is in these that 

 Dr. Spitta best shows his grip of the subject. They teem with 

 useful practical hints, and no one, whether a beginner or an 

 advanced worker, can peruse these chapters without adding 

 considerably to his knowledge. We have our doubts whether 

 the author does not lay too much stress on the necessity of 

 working only with the best, .and therefore the most expensive 

 apparatus. One of the greatest deterrents to the popularizing 

 of photo-micrography among students has been the idea that 

 good work can be done only with apparatus possessing the most 

 expensive refinements in the way of mechanical adjustments to 

 stages, condensers, lamps and objectives. For the few who do 

 critical, high power work, these are essential, but not so for the 

 majority for whom this book is intended, and who seldom soar 

 above good medium power work. The two chapters on the 

 microscope lenses, eye-pieces, and condensers are not, however, 

 without considerable value, and, like the rest of this admirable 

 work, they will well repay a careful perusal. The book is admir- 

 ably printed and is profusely illustrated with sixty-three text 

 illustrations and forty-one exquisite half-tone reproductions 

 of the author's own photo-micrographs. 



The Sound of a Voice thatis Still. By Archie Campbell. (George 

 Redway.) 5s. Accepting the good faith of the writer of this 

 book, which his preface forbids us to doubt, we could wish that 

 the voice in question had remained still until its owner had 

 been able to make himself more familiar with his subject, or to 

 adduce some new fact or fresh incident in his relations with the 

 unseen universe. As it is, the book is of the earth earthy, the 

 manner is almost brutal in its matter-of-fact directness, and its 

 characters are of the most commonjilace order. The intro- 

 duction into such a circle of some spirits of the great departed 

 is altogether too thin, and can only make the reader very tired 

 of the Laird of Auchenoullen. 



,/ounial of the Soi-iety of Comparatire Ler/islalion. Edited for 

 the Society by John Macdoneli and Edward Manson. (John 

 Murray.) 5s. This is the first ]iart of a new series, and con- 

 tains a number of valuable articles, together with a review of 

 the legislation of the Empire for 1897, with an introduction by 

 Sir Courtenay Ilbert. A very useful article is contributed by 

 Sir. Edward Manson, the Secretary of the Society, on " The 

 Status of English Trading Companies Abroad." 



BOOKS RECEIVED. 



Annual Seport of the Board of Segents — Smithsonian Institution, 

 to Jul:/, 1S97. 



Gilbert White's The Natural History of Selhorne. Parts I., II., 

 III., and IV. Edited by Grant Allen. (Jolin Lane.) Illustrated. 



Technical Edvciifion Seturns (England, Wales and Ireland), 29th 

 Julij, 189S. (Eyre & Spottiswoode.) la. 3tl. 



thornton-Pickard Album of Prize Pictures. (Dawbaru & Ward.) 



Phenomena of Nature as seen from the WorJishop and the Field, 

 Part II. JJy .laim's Walter. (Souneuschein.5 2s. 6d. 



A Manual of Library Cataloguing. By J. Henry Quinn. (Library 

 Supply Co.) 53. not. 



The Naval Pioneers of Australia. By Louis Becke and Walter 

 Jeffery. (Murray.) Illustrated. 7s. 6d. 



The Hygiene of the Mouth. By R. Deuison Pedley. (J. P. Segg 

 & Co.) illustrated. 28. 6d. 



Current Papers, No. S. By H. C. Eussell, p.B.s. With plates. 

 (Read before the Royal Society of New Soutli Wales. ) 



Applied Geology. Part II. By J. V. Elsden, B.Sc. (Quarry 

 Publishins; Co.) Illustrated. 



The International Directory of Boohsellers and Bibliophile's 

 Manual, 1S99. (Aldiuc Press : Rochdale.) Lis. 



Energi/ and Heat. By John Roger. (Spon.) Illustrated. 23. 



Telephones: their Construction and Fitting. Sifth Edition. By 

 F. C. AUsop. (Spon.) Illustrated. Ss. 6d. 



The Entropy Diagram. By J, Boulvin, (Spon.) 5s. 



