November i8, 1897] 



NATURE 



Luxor, and Assouan ; the drying power of the air at the 

 temperature of the air ; and the drying power of the air 

 at the temperature of the body. 



Les Fours Elecirigues et leiirs Applications. Bv Ad. 



Minet. Pp. 178. (Paris: Gauthier-Villars et Fils ; 



Masson et Cie.). 

 All thermo-electric effects in which electricity is the 

 prime agent are regarded by the author as coming within 

 the scope of the title of this book, the grounds being 

 that all forms of apparatus for converting electrical 

 energy into heat, come under the generic head of fours 

 I'lectriqucs. The book thus includes not only descrip- 

 tions of electric furnaces in which temperatures ap- 

 proaching four thousand degrees are reached, but also of 

 simple conductors and resistance coils raised a few de- 

 grees above the temperature of the atmosphere by the 

 electric current. The first part of the volume is devoted 

 to an account of the heating effects of electricity ; it in- 

 cludes descriptions of the heat produced by a current 

 passing through a metallic resistance, the maximum 

 temperatures of conductors, and electric heating gene- 

 rally. The remaining three parts deal with the electric arc 

 and arc carbons of various forms, electric furnaces and 

 their applications, and carbide of calcium and acetylene. 



It will thus be seen that portions of the book are not 

 exactly pertinent to the title, nevertheless they assist the 

 reader to a clear understanding of electro-thermal 

 phenomena. The section on electric furnaces is a con- 

 cise account of the various forms of furnace devised for 

 different purposes. 



The book belongs to the Encyclopedie scientifique des 

 Aide-Memoire series edited by M. Leaute. 



LETTERS TO THE EDITOR 



Bibliography of X-Ray Literature and Research (1896- 

 1897)7 being a Ready Reference Index to the Literature 

 on the Subject of Rontgen or X-Rays. Edited by 

 Charles E. S. Phillips. With an Historical Retrospect, 

 and a chapter of " Practical Hints." Pp. xxxvii -f 68. 

 (London : The Electrician Printing and Publishing 

 Co., Ltd.) 

 The work before us gives, in a handy and succinct form, 

 a good deal of information respecting the literature of 

 X-rays. The subject proper of the volume is prefaced 

 by a brief historical retrospect, in which, however, the 

 average worker in physics will find little but what is 

 already known to him, and a short chapter of practical 

 hints intended "to appeal more especially to physical 

 students about to turn tlieir attention to high vacua re- 

 search." The main and most valuable portion of the 

 book is the bibliography, and this should certainly prove 

 of utility to investigators in this branch of science. The 

 volume, so far as we have been able to test it, appears to 

 have been compiled with great care, and certainly a 

 mass of useful knowledge is here gathered together in 

 a form easy of reference. 



Die Meteoriten in Sainnilungen und ihre Literatur, nebst 

 einein Versuch den Tauschwert der Meteoriten zu 

 bestinimen. Von Dr. E. A. Wiilfing. Pp. xlvi -f 460. 

 (Tiibingen : Laupp, 1897.) 

 The author has sought information relative to the 

 meteorite collections, public and private, from those in 

 charge of them, and has collated and indexed the results 

 in the form of an alphabetical list, giving for each pre- 

 served meteorite a statement of the date of fall or find, 

 a list of the more important memoirs relating thereto, 

 and the weights preserved in the various collections. 

 The work has been carefully done, and will be very use- 

 ful to collectors of these extra-terrestrial bodies. As 

 regards the pecuniary values to be assigned to the 

 meteorites, we are afraid that the dealers will eschew all 

 such mathematical calculations as are suggested by the 

 author, and will in each case get, as heretofore, what 

 they can. 



NO. 1464, VOL. 57] 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 vianuscrift/s intended for this or atiy other part of Nature. 

 No notice is taken of anonymous communications.'\ 



Rediscovery of the Tile-fish (" Lopholatilus "). 



I AM indebted to Dr. John Murray for drawing my attention 

 to an error in the address which I had the honour of delivering 

 before the Linnean Society on May 24. In referring to the dis- 

 covery and subsequent remarkable disappearance of the Tile- 

 fish (Lopholatilus chanueteonticeps), I stated that since the year 

 in which the extraordinary mortality in this species had been 

 observed (1882), "no .specimen of the fish has ever been found." 



I must take an early opportunity of correcting this error, 

 which I might have easily avoided by reading more carefully the 

 concluding paragraphs of Goode and Beane's account of the 

 Tile-fish in " Oceanic Ichthyology," p. 288, from which I may 

 be allowed to quote as follows : 



" In the fall of 1892, Colonel Marshall McDonald, the Com- 

 missioner of Fisheries, made another attempt to discover the 

 fish, and was successful, obtaining it from the following stations 

 [five stations are enumerated, on which eight specimens were 

 caught]. The Tile-fish then is restored to the list of existing 

 species of our North Atlantic coast, and it is probable that in 

 time it may attain to its former abundance. The temperature- 

 investigations made by Colonel McDonald have been carefully 

 discussed by him, and he is convinced that the destruction of 

 Lopholatilus was due entirely to climatic causes." 



What these climatic causes are we learn from a report by 

 Prof. William Libbey, jun.. published in the U.S. Fish Com- 

 mission Report for 1893 (Washington, 1895, 8vo), p. 32 ; they 

 consist in a variation of the relations of the Gulf Stream to the 

 Labrador current, affecting the temperature of a certain area 

 inhabited by the fish. A lowering of the temperature by the 

 latter current is believed to have caused the sudden mortality, 

 whilst a subsequent invasion of warm Gulf Stream water would 

 allow the fish to gradually reoccupy the depopulated area. 



Kew Gardens, November 14. A. -Gunther. 



The Exploration of the Air by Means of Kites. 



The highest kite ascent, described in Nature of October 7, 

 was in turn exceeded here by more than 1800 feet on October 15, 

 when excellent meteorological traces (of which a facsimile is 

 enclosed) were brought down from a height of 11,086 feet above 

 Blue Hill. The flight was effected with only four kites, and 

 the ascent and descent occupied but four and a half hours. 

 Excepting a more rapid decrease of temperature with increase 

 of elevation, the results agree with those already stated for the 

 previous high flight. 



I now desire to call attention to the fact that the deductions 

 from our automatic records obtained with kites seem to confirm, 

 in general, the conclusions reached by Messrs. Welsh and 

 Glaisher from their observations in free balloons many years ago 

 in England. For example, we find also that the most rapid 

 decrease of temperature with height occurs usually in the lower 

 mile of air during the daytime, and, even with no visible clouds, 

 that damp strata often exist in the dry air of the upper regions. 

 A discussion by Mr. Clayton of more than one hundred meteor- 

 ological records, obtained with kites since 1894, is now in the 

 press, and will form an appendix to Part i. vol. xlii. of the 

 Annals of the Astronomical Observatory of Harvard College. 



A curious illustration of how identical methods sometimes 

 may serve diametrically opposed investigations, is the applica- 

 tion of the deep-sea sounding apparatus of Sir William Thomson 

 (now Lord Kelvin) to bring do^vn these aerial soundings. 



A. Lawrence Rotch. 



Blue Hill Meteorological Observatory, November i. 



Lord Rayleigh's Proof of Van 't Hoff's Osmotic 

 Theorem. 



In what follows I shall understand by " Van 't Hoffs Osmotic 

 Theorem," the statement, that if P, V be the osmotic pressure 

 and volume of unit mass of a solute, and /, v the gas- pressure 

 and volume of the same mass of the same substance supposed 

 gaseous at the same temperature, then pv = FV. 



