50 



NA TURE 



[May 17, i8q4 



spite of what has been recently done with regard to this 

 most fascinating puzzle in astronomy. The remainder of 

 this book deals briefly, among other things, with nebulw, 

 star clusters, comets and their spectra, spectroscopes, 

 &c. The chapter on atmospheric light phenomena has 

 received but little alteration ; in it are described 

 refraction, mirages, halos, twilight, &c., which call for 

 little if any change. 



In the third book we are introduced successively to 

 chapters on the distribution of heat on the earth's sur- 

 face, the pressure of, and disturbances in, the atmosphere, 

 and hygrometry ; these may be all included in the word 

 " meteorology." In the science of meteorology very rapid 

 advance has been made, and the last twenty years have 

 witnessed changes which have been sweeping in their 

 nature. Such being the case, we expect to find here 

 considerable alterations and additions, and indeed we 

 are not disappointed , for we find this part " zum 

 grossen Theile giinzlich umgearbeilet." Thus, to 

 mention one or two instances, the Ice age is dealt with 

 at some length, and is accompanied by an excellent map 

 showing the glacial distribution. The paragraphs on the 

 internal heat of the earth are also likewise lengthened, 

 and much new matter inserted. In the section on earth- 

 quake?, on the other hand, we fail to notice any reference 

 to Prof. Milne's important work that he has been carrying 

 out in Japan on a truly scientific basis. A brief de- 

 scription of this, and a few words on the seismograph, 

 would have made an interesting addition. 



The fourth and last book will be found to have 

 received little alteration. This seems perhaps striking, 

 in the face of the great amount of work that 

 is now being done in this direction. There is no 

 doubt that at present we are rather gathering facts 

 systematically and accurately acquired, than subjecting 

 those already obtained to detailed discussion. Never- 

 theless we find no changes or additions under the para- 

 graph entitled "dis spectrum des N'ordlichtes," or any 

 other explanation of this phenomenon than that of De la 

 Rive, indicating that the work done during the last 

 nineteen years has been void of results worthy of men- 

 tion. In the part on lightning, we are rather surprised 

 to see no reference to photography, which has en- 

 lightened us much on this phenomenon, showing us 

 that a forked flash is by no means "instantaneous," 

 to use a word which is rather ambiguous, but lasts, 

 comparatively speaking, a considerable time. 



We cannot conclude without referring especially 

 to the admirable illustrations, which throughout the 

 work form a very prominent feature. The plates 

 at the end of the b3ok miy be said to be the same as 

 those that appeared in the last edition, but in the case 

 of those in the atlas which accompanies the volume 

 many importantalterations and additions have been made. 

 Thus, to mention some of the more important. Those 

 showing the paths of the planets have been revised and 

 much improved. Two rather startling (as regards colour) 

 pictures of the planet Mars (June 3 and 14, 1858), after 

 Secchi, are inserted, also an excellent map of his 

 surface, after Schiaparclli. 



Among other very good plates is one of Jupiter and his 

 spots (Warren de la Rue), Saturn I'rouveloi;, two of the 

 moon after negatives taken at the Lick Observatory, 

 NO. I 28 I, VOL. 50J 



Mount Hamilton, a lunar crater after Nasmyth, 

 Roberts' Andromeda nebula, and Langley's enlarged 

 picture of sun-spots. 



The maps and diagrams referring to the meteorologici 

 and magnetical sections are as numerous as ever, ui I 

 have all been carefully revised and brought up to d>!- 

 New pictures of the aurora;, as observed in Kingua Kjord 

 in 18S2 and 1S83, are also inserted. 



In the above rapid survey of the 900 pages which this 

 book contains, one can form an idea of the great dilHculty 

 the bringing of such a work as this up to date must have 

 been to the reviser. Having to bear in mind that no part 

 must be more elaborately developed than another, aad 

 that the limit of range as regards details must be re- 

 stricted. Dr. Peters has had no light task before hun. 

 Cosmical physics is such a wide-spreading subject, and 

 the information here brought together so plentiful, that 

 the few remarks we have mide ab^ive fall, for the ni'st 

 part, into insignificance. 



As a popular treali:e the work should be widely read, 

 and the special index should considerably facilitate ilie 

 utility of the work in its function as a book of reference 



W. J. LOCKYEK. 



ALCHEMY AND CHEMISTRY. 



The Alchemical Essence and the Chemical Element, an 

 Episode in the Quest of the Unchangin\;. By M. M. 

 Pattison Muir. Pp. 94. (London : Longmans, Green, 

 and Co., 1S94.) 



THIS is a very interesting book ; its object is stated 

 in a sentence printed on a fly-leaf following the 

 title-page— " This essay is written in the hope that 

 some of the men who exercise their ' wit and reason' in 

 examining the problems of life may help to answer the 

 questions that nature propounds to those of her students 

 who follow the quest of the unchanging.' 



The author begins by quoting two definitions, one 

 an alchemist : "There abides in nature a certain fon.i 

 matter which, being discovered and brought by ait 

 perfection, converts to itself, proportionally, all imperii i 

 bodies that it touches'"; and the other by a chcnii^^i : 

 " In chemistry we recognise how changes take pl.acc m 

 combinations of the unchanging." It may here be said 

 that it would often materially add to the interest of the 

 work if the names of the authors of these and of otl: 

 quotations in the book had been given. 



The difficulties that many have experienced in under- 

 standing the writings of the alchemists are accounted 

 for by showing that the names which they used, and 

 which have survived as the names of well-knowni 

 substances, were applied only to certain principles or| 

 properties that matter was supposed to possess: thuS| 

 the word sulphur re[. resents the principle of change-, 

 ability, and the word mercury the principle of malleability 

 and lustre which the metals exhibit. The alchemists 

 used expressions of this kind partly to hide their scu' 

 from the uninitiated, and also to preserve themscl^ 

 from suspicion of dealing with the evil one, who was con 

 sidered to be the possessor of the earth. The mystical 

 language was derived, to a large extent, from theology, 

 the science which at that time pervaded all the thoughts 



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