230 



KNOWLEDGE. 



[October 1, 1895. 



weight, atoms of different elements have different weights. 

 Sir Henry Eoscoe shows, by means of notes found in 

 the poFsessicn of the Manchester Literary and I'hilo- 

 gcphical Society, that "it was the application of the 

 principle of the Newtonian atom to the constitution of the 

 gases contained in the atmosphere that led Dalton to his 

 atomic theory. " Dalton died on July 27th, 1844. Man- 

 chester, where he resided for fifty years, has done honour 

 to his memory, not only by securing the tine statue of 

 him which now adoins the grand entrance of the magnifi- 

 cent town hall, but also by establishing a scholarship for 

 scientific research. To those who think that great 

 cleverness is essential to success, we commend Sir Henry 

 Eoscoe's sketch of Dalton's life and work. And especially 

 would we call attention to what Dalton himself remarked 

 in his later life. " If," said he, " I have succeeded better 

 than many who surround me, it has been chiefly — nay, I 

 may say, almost solely — from unwearied assiduity." It 

 only remains for us to say that the book is an admirable 

 one to put into the hands of every young student of 

 science. 



Solution and Kh'ctwhj.v's. By W. C. D. Whetham, M.A. 

 (University Press, Cambridge.) This handy little volume 

 is one of the up-to-date Cambridge natural science 

 manuals which are being edited by Mr. Glazebrook. 

 Notwithstanding Mr. Pattison Muir's admirable translation 

 of Ostwald's " Solutions " and Prof. Palmer's edition of 

 Nernst's " Theoretische Chemie," a short epitome of the 

 recent work done on the border-land between chemistry 

 and physics has been needed for many years, and Mr. 

 Whetham has already shown, although still a young man, 

 by his papers on the velocities of the ions, and other work, 

 that he is fully conversant with this modern development 

 of physico-chemistry. If we except, in addition to the 

 author's own work, that of Ramsay and his pupils, 

 Pickering and a few others, this new science evolved from 

 the application of the gaseous laws to the phenomena of 

 solution and osmotic pressure, although so fruitful on the 

 Continent, has received little attention at the hands of 

 English investigators. We therefore hope that Mr. 

 Whetham's book will be read by many of the younger 

 men, and that it will induce them to turn their attention 

 to what is undoubtedly destined to be of considerable 

 importance in modifymg our ideas about matter and its 

 motion. Some years ago the British Association appointed 

 a committee to inquire into the subject of electrolysis, 

 and the discussions which took place at that time helped 

 in crystallizing the ideas concerning the freedom of the 

 ions in electrolysis and their behaviour under electrical 

 pressure. The extension of these generalizations to solution 

 phenomena has followed since that date, so that tbe two 

 subjects of solution and electrolysis are very liily included 

 in the present volume. Not the least valuable portion of 

 (he book are the tables of electrochemical properties 

 which conclude it. 



BOOKS EECEIVED. 



i The Serscheh and Modern Ash'onomif. By Agues M. Clertci-. 

 •(Cassell ) Ilhistrateil. 3s. 6d. The Century Science Scries. 

 ' Justus Von Liehii], his Life and Work. By W. A. Sheustone 

 (Cassell.) Illustrated. Ss. 6d. The Century Hcieucc Series. 



The Unglinh Lalces. By Hugh Eobert Mill", D.Sc. (Philip & Son ) 

 Illustrated. ,Ss 6d. 



Philips' Si/s/ema/ic Alias and Philips' Sandy- Volume Alias. By 

 E. G. Kayenstein. (Philip & Son.) 



Consider Ihe Hearens : A Popular Inlroduetion to Astronomti. 

 By Mrs. \V. Steadman Aldis. (Religious Tract Society.) Illu&trattd. 



Notes on the Nebular Theory. By William Ford Stanley. (Kegan 

 Pau'..) Illustrated. 



The Orltjin of Plant Strurlures. By Eey. Geo. Henslow. (Kegau 

 Paul.) 5s. The International Scientific Series. 



Anah/lical Ke;i to Flowering Plants. By Franz Thormer 

 (Swan Sonuensehein.) 28. 



HHdeu Beaiiiies of Nature. By Richard Kerr. (Religious Tract 

 fociety.) Illustrated. 



A Lahoralorii Manual of Orijanic Chemtstrif. By Dr. Lassar-Cohn. 

 Translated by Alex. Fmitli, B.^'c., &c. (MacmiUa'n.) 89. 6d. 



Seport on the Total Eclipse of the Sun observed at Mina Bronces, 

 Chile, on April 16/*, 189.3. By ■ J. M. Schaeberle. (Sacraraento: 

 State Office.) Illustrated. 



A Study of the Physical Characteristics of Comet Bordame. By 

 W. J. HuBsey. 



Shakespeare. By Dayid Charles Bell. (Hodder & Stoughton. 

 3s. fd. Bell's Readers. 



Elements of Modern Chemistry. By Charles Adolphe Wurtz. 

 Fifth Edition! Reyised and Enlarged by W. H. Greene and H. E. 

 Keeler. (Lippincott.) IlUi>trated. 



THE VISIBILITY OF CHANGE IN THE MOON. 



By H. G. Wells, B.Sc, Author of the " Time ]\Iachine." 



THE absolute quiescence of the lunar crust is a 

 commonplace of popular science; it is, however, 

 open to doubt whether the belief in the permanence 

 of the lunar surface has all the justification its 

 wide acceptance might lead us to expect. This 

 conclusion has been drawn from the absence of any percep- 

 tible change in the forms of lunar contours, and of any 

 visible eruptive phenomena. But it must be remembered 

 that fairly extensive changes of contour may have occurred 

 before the epoch of lunar photography, and that even now 

 the displacement of relatively large masses has a very fair 

 chance of escaping notice. As Mr. Elger has pointed out, 

 objects as large as Monte Nuovo or .loruUo might come 

 into existence in many regions without anyone being the 

 wiser, and a catastrophe as extensive as the destruction 

 of Herculaneum and Pompeii might still escape detection. 

 And few people outside astronomical circles probably 

 appreciate the peculiar consequences the physical conditions 

 of our satellite's surface would have upon the phenomena 

 of volcanic eruption. 



The most striking features of a typical volcanic eruption 

 upon our planet are certainly the tumultuous noises of the 

 outbreak, and the enormous clouds of steam and pumiceous 

 ashes that rush out of the vent and spread over the 

 country encircling the volcano. These cloudy masses 

 form a background to reflect and exaggerate whatever 

 incandescence may be visible within the crater. But upon 

 the moon all this pomp of smoke and flame would be 

 absent, because upon the moon there is no atmosphere to 

 buoy up the finely divided products of the eruption, and 

 whatever the volcano threw out would, so soon as the 

 velocity of its projection was lost, fall back at once upon 

 the lunar surface. The uprush of flames, which is another 

 striking accompaniment of terrestrial outbreaks, would also 

 be absent, since a llame rushes upward only because it is 

 specifically lighter than the air through which it rushes. 

 The intense cold of the hmar surface, together with the 

 absence of atmospheric pressure, would also conspire to 

 rob any incandescent gas of its visibility, for so soon as it 

 was released at the vent it would expand and cool, and so 

 elude our observation. A momentary disclosure of mcan- 

 descence is all we can anticipate under the most favour- 

 able circumstances, and in the bright glare of the lunar 

 day — and it is only the lunar day we are accustomed to 

 observe— it is conceivable that the equivalent of the most 

 violent terrestrial eruptions might be going on in the field 

 of our largest telescope without attracting attention. 



Even could one stand upon the moon itself near the 

 vent, the phenomena of an eruption in progress would still 

 be far less awe-inspiring than u on this planet. In a pro- 



