400 



NATURE 



[February 23, 1905 



little doubt that such a society must tend to the spread of 

 knowledge and the improvement of method in pottery manu- 

 facture. 



An interesting paper by R. Krcmann on the melting point 

 of dissociating substances and the degree of dissociation 

 during melting is contained in the Silstingsberichte (1904, 

 vol. ciii., part vii.) of the Imperial Academy of Sciences 

 of Vienna. From theoretical considerations involving the 

 law of mass action, melting-point curves are deduced for 

 substances, such as the compounds of phenol with aromatic 

 bases and with picric acid, at different degrees of dissoci- 

 ation. By comparing the shape of these curves with those 

 obtained, for instance, on adding aniline to the compound of 

 aniline and phenol, the actual degree of dissociation of these 

 substances during melting may be very approximately ascer- 

 tained. Incidentally, the important result is established that 

 the addition of one of the products of dissociation of the 

 compound may in many cases cause a rise in the melting 

 point without there being question of the formation of an 

 isomorphous mi.xture. The results obtained are applied to 

 an investigation of the additive compounds of nitroso- 

 dimethylaniline with various aromatic bases. 



In an inaugural dissertation for a doctorate at Bonn 

 University, Herr Jacob Steinhausen presents the results 

 he has obtained during a research on " enhanced lines." 

 Adopting the English name originally proposed by Sir 

 Norman Lockyer, the author gives a detailed description 

 of the enhanced lines and their different appearances in 

 various spectra, and then describes the apparatus and 

 methods employed by him in his own research. Using a 

 small grating of i metre radius, which produced a dis- 

 persion such that 10 Angstrom units extended over 

 0.595 "!"■'• °" ^^^ plate; he photographed and compared 

 the arc and spark spectra of the elements AI, Sb, Pb, Cd, 

 Mg, Hg, Bi, Sn, Zn, Ba, Ca, Sr, and TI, using in most 

 cases metallic poles for the spark, and powdered metal, or 

 salt, on carbon poles for the arc. The wave-lengths are 

 only given to the nearest unit, and will, therefore, need 

 re-determining, with a larger dispersion, before they become 

 of any great use for stellar identifications. In discussing 

 the nature of the lines the author adopts an error made 

 by Prof. Kayser (" Handbuch der Spectroscopic "), viz. 

 that in accounting for spectral variations Sir Norman 

 Lockyer has always considered only the temperature of 

 the spark as the cause ; yet it is now more than thirty 

 years since the discoverer of enhanced lines explicitly 

 stated that the possible effects of electrical variations must 

 be included in the general term " temperature." 



Some ten years ago Prof. H. Moissan, in the course of 

 his work on the production of carbides in the electric 

 furnace, prepared aluminium carbide and showed that in 

 contact with water pure methane was evolved, thus giving 

 a new and direct synthesis of this important hydrocarbon. 

 In the current number of the Comptes rcndus (February 13) 

 Prof. Moissan and M. Chavanne give an account of their 

 determinations of the physical constants of pure marsh gas 

 prepared in this way. The methane, after being freed 

 from traces of moisture and less volatile impurities by 

 passing through a tube cooled to —85° C, is solidified by 

 cooling with liquid air, and any more volatile gases pre- 

 sent pumped away. The gas allowed to boil off from the 

 crystals was proved to be pure by a combustion analysis, 

 and possessed at 0° C. and 760 mm. pressure a density of 

 05547, t^G theoretical density being 0555. The melting 

 and boiling points were measured by means of an iron- 

 Constantin thermocouple, previously standardised against 

 a petroleum ether thermometer, the crystals melting sharply 

 NO. 1843, 'VOL. 71] 



at —184° C. and boiling at —164° at atmospheric pressure. 

 The authors add that the methane, purified in this way, 

 always possessed a sweet, faint garlic odour, which cannot 

 be attributed to impurities, and must be regarded as due 

 to the gas itself. The reaction between solid methane and 

 liquid fluorine was studied at the same time ; the two sub- 

 stances instantly combined, the reaction being accompanied 

 by a bright flash and a violent explosion, completely pul- 

 verising the glass tubes. 



A TWELFTH edition of Mr. \V. T. Lynn's booklet on 

 " Remarkable Comets " has been published by Messrs. 

 Sampson Low, Marston and Co., Ltd. 



The Cambridge University Press has published the first 

 number of a new scientific periodical entitled the Journal 

 of Agricultural Science. The magazine is edited by 

 Messrs. R. H. Biffen, A. D. Hall, T. H. Middleton, and 

 T. B. Wood, in consultation with Messrs. W. Bateson, 

 F.R.S., J. R. Campbell, and W. Sommerville. It is 

 intended to circulate among agricultural teachers and 

 experts, and will be issued, as material accumulates, in 

 parts of about one hundred pages. Each volume will con- 

 sist of four parts. The first number appeals to workers 

 in many departments of agricultural research, and among 

 the articles it contains may be mentioned those on Men- 

 del's laws of inheritance and wheat breeding, by Mr. R. H. 

 Biffen ; the influence of pollination on the development of 

 the hop, by Mr. A. Howard ; the importance of the removal 

 of the products of growth in the assimilation of nitrogen 

 by the organisms of the root nodules of leguminous plants, 

 by Mr. J. Golding ; the analysis of the soil by means of 

 the plant, by Mr. A. D. Hall ; variation in the chemical 

 composition of the swede, by Mr. S. H. Collins; soil 

 analysis as a guide to the manurial treatment of poor 

 pastures, by Messrs. T. B. Wood and R. A. Berry ; and 

 the improvement of poor pastures, by Prof. T. H. Middle- 

 ton. The magazine should prove of interest and help to 

 all teachers of agricultural science as well as to those 

 engaged in research in this field of knowledge. 



The third part of Herr C. K. Schneider's " lUustriertes 

 Handbuch der Laubholzkunde " has just been published by 

 the firm of Gustav Fischer, Jena. The first two parts 

 were reviewed in Nature of November 24, 1904 (vol. Ixxi., 

 p. 76), and a further notice will appear after the work, 

 consisting of about nine parts, has been completed. 



OUR ASTRONOMICAL COLUMN. 

 Ephemeris for Comet 1904 e. — The following is an 

 extract from a continued ephemeris for comet 1904 e, as 

 calculated from M. Fayet's elliptical elements by Dr. E. 

 Stromgren, and published in No. 3994 of the Aslronomische 

 Nachricliten : — 



Ephemeris 12)1. (jl/.T. Berlin). 

 1905 a (true) S (true) log r log .i Bright- 



Feb. 25 ... 3 10 47 ... +30 7 ... 0-1669 ... 0-1233 ■■■ o'46 



Mar. I . . 3 22 3 ... +32 o ... 0-17H ... 0-1359 ... 0-43 



.> 5 ■■■ 3 33 44 •■■ +33 47 ■•• 0-1757 ... o 14^6 ... o 39 



„ 9 ... 3 45 49 . +35 25 ... o-iSos ... 0-1611 ... 0-36 



,, 13 ... 3 58 16 .. -1-36 56 ... 0-1855 ■-■ o 1736 ... 0-33 



The comet is now becoming very faint, and is travelling 



in a north-easterly direction through the southern part of 



the constellation Perseus. On March 11 it will pass near 



to { Persei. 



Revised Elements for Borrellv's Comet (1904 c). — 

 When publishing the previous set of elements for comet 

 1904 e, M. Fayet explained that, as his computations were 

 based upon the results of only a few observations, they 

 could only be regarded as approximate. Now. however. 



