420 



NATURE 



[December 12, 1912 



positive. Dr. H. B. Heywood inquired if Prof. 

 Moore had discovered any similar results for quadratic 

 forms other than positive ones. Such results would 

 be of use in the theory of Fredholm's equations. Prof. 

 Moore thought Mr. Hilton's suggestion a good one. 

 He had not discovered any results applicable to the 

 general quadratic form. He had been led to the 

 theorem of his paper by his work on Fredholm's 

 equation. 



Prof. J. C. Fields gave a new proof of a general 

 theorem relating to orders of coincidence. Major 

 MacMahon discussed the algebraic functions derived 

 from the permutations of any assemblage of objects. 

 Prof. W. Peddle described an apparatus for the solu- 

 tion of equations of the nth degree, which required, 

 however, that the equation should be prepared so that 

 the root required lay between o and i. In reply to a 

 query, he thought that the method would be more 

 expeditious than those usually employed. 



Dr. H. B. Heywood described the use of the ex- 

 ponential curve in graphics. For carrying out the 

 processes a template of transparent celluloid is used 

 upon which is marked a graduated exponential curve. 

 Operations of multiplication, division, evolution, 

 differentiation, and integration are performed. The 

 error is not greater than i per cent, except for differ- 

 entiation. 



An account was given by Dr. Nicholson of the 

 report of the committee for the tabulation of Bessel 

 and other functions. Four sheets of new tables of 

 elliptjc functions are given for four modular angles. 

 These are preceded by a statement by Sir George 

 Greenhill explaining the notation and the mode of 

 using the tables. The report includes some tables 

 (placed at their disposal by Prof. A. G. Webster, who 

 has calculated them) of some her and hel functions 

 and their derivatives. These tables will be of especial 

 importance to electrical engineering. 



Cosmical Physics and Astronomy. 

 The report of the committee on seismological inves- 

 tigations contains a detailed account of the various 

 seismic disturbances in the period 1904-09, thus ex- 

 tending the catalogue contained in last year's report. 

 Curves are given, relating to six large earthquakes, 

 showing the relation bjtween the amplitudes in 

 angular measure and the distance from the origin. 

 Sixteen instances are given in which the azimuth of 

 an origin determined from the maxima of the N.S. 

 and E.W. motion approximately agrees with the 

 azimuth as measured on a globe. In the same in- 

 terval there are twenty-six instances for which no 

 such agreement exists. The inference is that the 

 main portion of tcleseismic motion generally takes 

 place in directions independent of the azimuth of its 

 origin. Sections are devoted to the relative duration 

 of two rectangular components of earth movement at a 

 given station, megaseismic frequency in different 

 seasons, earthquake periodicity, a new periodicity (by 

 Prof. H. H. Turner, in which it is shown that besides 

 the period of about fifteen months, there is also 

 evidence that for the world as a whole seismic strain 

 usually finds relief every fifteen or thirty days), and 

 other matters. 



Prof. H. H. Turner explained further to the section 

 that further examination showed that some of the 

 deviations may be due to the existence of neighbour- 

 ing periodicities which have not been fully examined. 

 But attention has been concentrated on the existence 

 of pairs of periodicities or groups (analogous to double 

 lines or groups of spectra) by relative work on the 

 variations of level and azimuth of the Greenwich and 

 Cane transit circles. 



In the absence of Mr. J. T- Craig, Prof. Turner 



NO. 2250, VOL. 90] 



read a paper bv the former showing that there is a 

 connection between Prof. Schuster's metliod of 

 analysing a series of figures for suspected periodicities 

 and the method of correlation applied by Prof. Karl 

 Pearson to detect hidden connections between sets of 

 variables. 



Dr. S. Chapman, of Greenwich Observatory, gave 

 an account of an attempt to determine the total 

 number of the stars. He also read a paper by Prof. 

 Dyson (the Astronomer Royal) in which it was en- 

 deavoured to identify several chromosphere lines as due 

 to radium. Considerable scepticism seemed to be 

 shown by those present whether it was possible at 

 present to make sure of the identity on such short 

 spectra as are obtainable. Prof. Kayser expressed his 

 great interest, but considered that tfie relative intensi- 

 ties which had been quoted were very uncertain 

 because authorities differed. It was doubtful indeed 

 whether a stated intensity had any meaning. The 

 presence of helium seemed to be a point in favour of 

 the author. Prof, the Hon. R. J. Strutt remarked 

 that the spectral examination of terrestrial minerals 

 would scarcely show the presence of radium, and asked 

 whether the conditions in the chromosphere were such 

 as to enhance the lines or those of allied bodies, such 

 as barium. Prof. Rutherford said he would require 

 very great evidence indeed before accepting spectro- 

 scopic evidence of emanation in stars. Dr. Nicholson 

 argued that the presence of helium does not prove the 

 presence of radium. Father Cortie and Dr. Lockyer 

 both emphasised the shortness of the spectra. 



In a paper on magnetic disturbances, sun-spots, and 

 the sun's corona, Father Cortie examined the curves 

 for the period 1898-1911 of mean daily disc-area of 

 sun-spots, mean daily range of declination and hori- 

 zontal force, and yearly numbers of great and moderate 

 magnetic disturbances. There is a general accord in 

 the curves, but also notable discrepancies. F^- 

 example, the rapid fall of sun-spot curve 1909-11 was 

 accompanied bv a marked rise in declination, hori- 

 zontal force and moderate magnetic disturbances. 



The committee on magnetic observations at Fal- 

 mouth Observatory report the following mean values 

 of the magnetic elements for the year 191 1 : — 



Declination 17° 33'°' W. 



Inclination 66° 28-2' N. 



Horizontal force o" 18798 C.G.S. 



Vertical force o'43i72. 



The meteorological papers read have been described 

 in an earlier article (November 28, p. 369). 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



CAMBRlDGii. — Notice is given that the Plumian pro- 

 fessorship of astronomy and experimental philosophy is 

 vacant by the death of. Sir George H. Darwin, K.C.B. 



Mr. H. C. Robson, of Sidney Sussex College, has 

 been appointed chairman of the examiners for the 

 mathematical tripos, part i., 1913, and Prof. Seward 

 chairman of the examiners for the natural sciences 

 iripos, 1913. 



The professor of anatomy has appointed Mr. 

 E.. R. T. Clarkson an additional demonstrator of 

 anatomy. 



The matriculation of December 6 shows a total entry 

 of 1 156 freshmen up to the present date for the year 

 1912-13. This comjjares favourably with the similar 

 number of last year at the same date, which was 

 I III. 



Oxford. — On December 10 the honorary degree of 

 doctor of science was conferred on Prof. Ernest 



