438 



NA TURE 



[February i i, 1909 



ments. {2) By displacing the air during electrolysis with 

 a neutral gas (nitrogen) no appreciable difference was 

 observed in the weight of silver deposited; this is in agree- 

 ment with the recent measurements made at the National 

 Physical Laboratory, and contrary to the older measure- 

 ments of most of the earlier observers. (3) The value found 

 in the course of this research for the Weston normal cell, 

 in terms of the international ohm and international ampere, 

 agrees in a most satisfactory manner with the same results 

 of the Reichsanstalt in 1908, and shows a satisfactory 

 agreement with the recently published results of the 

 National Physical Laboratory. 



The explanation of the electrical and thermal properties 

 of metals as due to the existence of freely moving electrons 

 in the intervals between the molecules of the metal 

 has been a favourite theme with physicists for the last 

 ten years since Prof. Riecke first published his theory. 

 Although most of the theories have succeeded in giving 

 properties for the metals in general agreement with the 

 results of experiment, the quantitative agreement has not 

 been all that could be desired. In particular, the quotient 

 of the electrical and thermal conductivities, which has 

 throughout been a favourite quantity with regard to which 

 theory and experiment were compared, has, according to 

 the theories, been a simpler function of the temperature 

 than experiment has proved it to be. In No. 13 of the 

 Vcrhandlungen der dcutschen physikalischcn Gesellschaft 

 for 1908 Prof. P. Gruner, of Berne, suggests a modifi- 

 cation of the theory of Prof. Lorentz which will do some- 

 thing to remove this objection. The negative electrons 

 alone are supposed to be in motion, and when one impinges 

 on a neutral molecule with sufficient velocity it is sup- 

 posed to be capable of expelling an electron from the 

 molecule, and when it impinges on a positive molecule 

 with the requisite gentleness it may combine with the 

 molecule. Since the critical velocities can be chosen at 

 will, it is evident that Prof. Gruner's theory admits of a 

 closer fit between theory and experiment than has hitherto 

 been possible. 



The general report on the operations of the Survey of 

 India administered under the Government of India during 

 1906-7 has been received. The report was prepared under 

 the direction of Colonel F. B. Longe, R.E., Surveyor- 

 General of India. We notice that the scale on which 

 field surveys are to be executed and the larger scale 

 standard maps published has been decided. The general 

 scale of survey is to be i inch = i mile, but reserved forests 

 and special areas will be surveyed on the scale 2 inches = 

 I mile if required. The general scale for publication will 

 be I inch = I mile. Among special observations carried 

 out during the year under review may be mentioned those 

 in connection with the gravimetric survey. The deflection 

 of the plumb-line was determined at eleven stations in 

 Kdthidwdr and round the Gulf of Cambay, and the values 

 obtained were in accordance with the general character 

 of the deflections in Rajputana. Pendulum observations to 

 determine the variation in the value of gravity were made 

 at twelve stations in the neighbourhood of the Himalayas 

 and of the Siwdliks, and on or near the Great Arc. The 

 general character of the variations found was in accord- 

 ance with expectation, but local anomalies of considerable 

 amount were also disclosed. The results obtained have 

 been found to agree with those obtained by Prof. Hecker 

 in 1905. The magnetic survey was extended during the 

 year into Burma and Assam. The systematic observations 

 of Himalayan peaks in connection with the problem of 

 refraction were continued, and though the results are' of 



vo. 2050. VOL. yo] 



great interest many more arc required before definite con- 

 clusions can be drawn. The total out-turn of detailed 

 topographical and forest sui'veys on all scales was at the 

 lime of the report 25,740 square miles, against 23,312 

 square miles of similar surveys during the previous year. 

 The total area triangulated and traversed for survey pur- 

 poses was 31,851 and 1684 square miles respcctivelv, 

 against 27,134 for the previous year. 



Messrs. Bowes and Bowes, of Cambridge, have just 

 issued their latest catalogue of books on pure and applied 

 mathematics, dealing more particularly with books pub- 

 lished in the nineteenth century. 



Prof. J. Perry's well-known work on " Applied 

 Mechanics " has been translated into German by Herr 

 Rudolf Schick. " Angewandte Mechanik " is published by 

 the firm of Tcubner, of Leipzig and Berlin, at the price of 

 iS marks. 



KouR new volumes in the Philosophische Bibliothek 

 published by the Diirr'schen Buchhandlung, Leipzig, have 

 been received. No. 28 deals with Descartes 's principles 

 of philosophy, and is edited by Dr. A. Buchenau ; some of 

 the Emperor Julian's philosophical works, translated and 

 explained by Herr R. Asmus, form No. 116; a critical 

 analysis of .Schleiermacher's " Weihnachtsfeier, " by Herr 

 H. Mulert, appears as No. 117; and No. 118 is an 

 " Einfuhrung in die Erkenntnistheorie, " by Prof. A. Messer. 



Messrs. Chapman and Hall have published a third 

 edition of Mr. Frederick Hovenden's book, " What is 

 Life? or Where are we? What are we? Whence did 

 we come? And whither do we go? " The first issue of 

 the work was reviewed in Nature for April 7, 1898 (vol. 

 Ivii., p. S35), and it is sufficient to say that the present 

 edition has been revised in the light of the progress made 

 since the publication of the last edition, and an appendix 

 has been added. 



The Johns Hopkins University Circular for December, 

 1908, takes the form of a memorial volume to the late 

 President D. C. Gilman, first president of the Johns 

 Hopkins University, who ruled its destinies from 1876 to 

 1901. The circular contains the impressive and appreci- 

 ative addresses, delivered at the in memoriam services held 

 last November at the University, by the present president. 

 Dr. Ira Remsen, many of the University administrators 

 and professors, and by Dr. James Bryce, our Ambassador 

 at Washington. Numerous letters eulogising the late presi- 

 dent received by President Remsen are included, an article 

 from the Nation, and a biographical sketch. 



OUR ASTRONOMICAL COLUMN. 



Water-vapour Lines in the Sun-spot Spectrum. — In a 

 paper read before the Dublin meeting of the British 

 Association, and again in No. 5, vol. xxviii., of the Astro- 

 pltysical Journal, Father Cortie directed attention to certain 

 water-vapour lines in the solar spectrum which appear to 

 become intensified in the spot spectrum. E.xamining 

 ninety-one lines in the region D, to X 5953-386, sixty-four, 

 or 70-3 per cent., of which are due to water vapour, he 

 found that of the si.xty-four, twenty-nine, or 45 per cent., 

 are affected in the spectrum of the spot either as widened 

 or darkened lines. An examination of Hale's map showed 

 that sixteen of these twenty-nine lines were also shown 

 there as widened or darkened. 



On this evidence Father Cortie suggested that steam 

 may exist in the regions of sun-spots, and supported the 

 suggestion by Mr. E. E. Brook's statement that he found 

 the presence of water vapour essential for the laboratory 

 production of Fowler's magnesium hydride bands, bands 

 which are a prominent feature of the spot spectrum. 



