586 



NA TURE 



[October io, 1901 



a number of adjacent towns. As they cannot well have separate 

 universities, cannot the new municipalities unite in the same 

 spirit which animates the citizens of Edinburgh and Glasgow, 

 Manchester, Birmingham, Leeds and Liverpool, and help to 

 make a real university common to them all ? 



I cannot hope to exercise much influence on the progress of 

 events, but " out of the fulness ol the heart the mouth speaketh,'' 

 and I trust the views which I have expressed will not prove 

 to be discordant with those of our late colleague, the distin- 

 guished Principal of the University, to whom we all look with 

 hope and confidence for help in the solution of the multitudinous 

 and tangled problems which the University of London still 

 presents. 



At the conclusion of his address Prof. Tilden distributed the 

 prizes to the successful students. 



MATHEMATICS AND PHYSICS AT THE 

 BRITISH ASSOC I A TION. 



A LTHOUGH the number of members present at Glasgow 

 ■^ was much smaller than was expected, the attendance at 

 ' he meetings of Section A was well maintained. The papers 

 presented to the Section were unusually numerous, and endeavours 

 had to be made to restrict each speaker to the twenty minutes 

 allowed by the rules of the Section. These endeavours were 

 not always successful, and several papers which came late in the 

 programme had to be given in too condensed a form to be 

 properly appreciated. This was the case, unfortunately, with 

 the " Note on the Theory of the Michelson-Morley Experiment," 

 communicated by Principal Hicks. Prof. Morley, who was 

 present, did not feel justified in discussing the question without 

 having further details from Dr. Hicks. It is to be hoped that 

 the debate which arose after the meeting of the Section was 

 over, will lead to a repetition of these important experiments in 

 the light of the new theory. 



As in former years, the discussions which took place in 

 the Section, either impromptu or by arrangement, formed 

 some of the most interesting items of [the proceedings. 

 That on the magnetic effects of electrical convection was 

 opened by Dr. Cremieu with a description of his experiments, 

 all of which gave negative results. Dr. H. A. Wilson 

 pointed out several causes which might possibly account for 

 these results, but subsequent speakers expressed doubts as to 

 them being adequate. On the whole, as Lord Kelvin said, we 

 must wait for a repetition of the experiments under the simplest 

 possible conditions before we accept as final a conclusion against 

 which there is so much indirect evidence, and which, if accepted, 

 would necessitate the entire reconstruction of electromagnetic 

 theory. 



A paper by Dr. Guillaume introduced a discussion on the pro- 

 posed new unit of pressure, the megadyne per square centimetre, 

 which was received with favour by the Section. It is very nearly 

 the pressure exerted by a column of mercury 75 cms. long, at o" C, 

 at sea level in latitude 45', and differs therelore little from the 

 atmospheric unit at present used. Dr. Guillaume does not 

 propose to interfere with the thermometric scale, and it seemed 

 to be the opinion of the Section that when any change in the 

 scale is made it should be " rationalised," and for convenience 

 have a degree more nearly equal in length to a Fahrenheit than 

 to a Centigrade degree. The discussion opened by Dr. 

 Glazebrook was to have been on glass used ior all scientific 

 purposes, but on account of the small time at his disposal he had 

 to restrict his remarks to optical glass, and gave an account of 

 the advances made by Abbe and Schott in the construction of 

 glass having the optical properties necessary for producing 

 achromatic objectives. During the discussion it was pointed 

 out by Mr. Hinks that the durability of some of the new 

 glasses left something to be desired, one of the lenses in use at 

 Cambridge having become partially covered by a fungus the 

 removal of which would necessitate the taking apart of the 

 objective. 



Several of the reports of committees contained matter of 

 special interest. That of the Electrical Standards Committee 

 included the results obtained by Mr. S. Skinner on the slight 

 difference of the amounts of silver deposited by the same current 

 from solutions of silver nitrate in water and in pyridine. The 

 Seismological Committee finds that the wind accounts for certain 



NO. 1667, VOL. 64] 



frequent small movements of nhe seismograph trace whose source 

 had hitherto escaped detection. The report of the Committee on 

 Underground Temperature contained tables of observations of 

 temperature made in Michigan and in Silesia, down to depths of 

 about 2000 metres. It seems, however, of little value to publish 

 such tables without information as to the nature of the strata 

 met with at different depths. The report of the Committee on the 

 Determination of Magnetic Force on board Ship consisted of 

 Captain Creak's description of the modified dip circle he has 

 devised for carrying out the determination by Lloyds' method. 

 The tests of the instruments having proved them satisfactory, two 

 have been sent out in the Discovery, and one in the German ship 

 Gauss, for use in the Antarctic. 



Of the ordinary communications, that by Lord Kelvin on 

 the absolute amount of gravitational matter in any large 

 volume of interstellar space probably attracted the largest 

 audience. Lord Kelvin gave a rL'snmc of the arguments he 

 brought forward in the Philosophical Magazine for August, to 

 show that if 25 million years ago 1000 million masses equal 

 to that of our sun had been distributed through a sphere of 

 radius 3 x 10"' kilometres they would have now acquired 

 velocities about equal to those known to be possessed by the 

 stars visible to us. It seems, therefore, probable that the total 

 amount of gravitation matter of our univ-erse does not differ 

 greatly from that of 1000 million suns. The same line of 

 argument may be carried out for the mass distributed as atoms 

 initially throughout space, and we then have the nebular 

 hypothesis reduced to atomic dynamics. 



Prof. Gray gave an account of the ^ work he is doing in 

 conjunction with his pupils on the viscosities of liquids and 

 solids and the effect on them of changes of temperature, magnet- 

 isation, l\;c. Some of the most interesting of the results obtained 

 were communicated to the Royal Society in June, and the 

 experiments seem likely to have an important bearing on 

 molecular theory. Dr. J. T. Bottomley's paper on radiation 

 of heat and light from a heated solid was taken at the end of a 

 sitting and received scant attention considering the importance 

 of the subject. Dr. Bottomley finds by measuring the power 

 absorbed by electrically heated polished or blackened platinum 

 wire and strips placed in vacuo, that at the same temperature 

 the blackened radiates four or five times as much energy as the 

 polished surface, and that when the luminous appearance of the 

 two is the same their temperature is practically the same. 

 Prof. Morley and Mr. Brush have been determining the 

 influence of water vapour on the energy lost by a heated 

 body placed in an enclosure containing air, hydrogen or water 

 vapour. At low pressures water vapour transmits heat 

 more rapidly than air, but not so rapidly as hydrogen. 

 In this connection Prof. Morley has devised a new pressure 

 gauge capable of measuring pressures down to about a ten- 

 thousandth of a millimetre of mercury. It consists of a U-tube 

 containing mercury, on one of the free surfaces of which the 

 pressure to be measured acts. The depression produced is 

 measured by the amount of till of the tube necessary to bring the 

 two mercury surfaces back into contact with tw'o platinum 

 points in the tube. A complete account of the arrangement is 

 to appear shortly in the American Joitvnal of Science, 



Prof. Callendar communicated the results of applying a 

 small correction hitherto thought negligible to the values 

 of the specific heat of water between o' and 100° C, 

 determined from the observations of Dr. Barnes with Cal- 

 lendar's apparatus. The high degree of accuracy which Mr. 

 E. H. Griffiths has attained in measuring temperature by 

 the platinum thermometer has enabled him to determine the 

 depression of the freezing points of extremely dilute solutions, 

 and as a result he can now state that the depression produced 

 by dissolving one gram-molecule of potassium chloride in a 

 thousand grams of water is, to about one part in two thousand, 

 double that produced by the solution of one gram-molecdle of 

 sujjar. 



Mr. B. Hopkinson brought forward a new argument for 

 the existence ol an ether, .although at certain times the two 

 stars of a spectroscopic binary are moving in opposite directions 

 at right angles to the line of sight with great velocities, the 

 doubling to be expected, if aberration is due to relative motion 

 of source and receiver, has never been observed. Aberration 

 must then be due to the motion of the receiver with respect to 

 something not matter, and be unaffected by relative motion of 

 this something and the source. This "something" is the 

 ether. Dr. Johnstone Stoney was unable to attend the meeting, 



