January 7, 1909] 



NA TURE 



299 



The annual meeting of the Association of Directors and 

 Secretaries for Education was held on January i in the 

 council chamber of the London County Council, when an 

 address on " The Finances of Education " was delivered 

 by Mr. W. Avery Adams, chairman of the association and 

 secretary to the Bristol Education Committee. In open- 

 ing his address, Mr. .Adams said that the scheme for 

 raising the Bristol University College to the rank of a 

 university, owing to the generosity of Mr. H. O. Wills, 

 promises shortly to be carried into effect, thus securing 

 for the west of England the same opportunities for intel- 

 lectual and professional training as are available in other 

 parts of the country, .\lluding to the Scottish Education 

 Act, he directed attention to the powers which are to be 

 granted to school boards in Scotland to compel attendance 

 at continuation classes up to the age of seventeen. If 

 such a remedy for the educational leakage which now 

 went on is practicable in Scotland, said Mr. Adams, surely 

 it is not unreasonable to suggest that it is practicable in 

 England. The principal theme of the address was the 

 finances of education, and Mr. Adams insisted that one of 

 the chief hindrances to progress is the financial strain now 

 put upon the local education authorities (i) by the imposi- 

 tion on the part of the State of new and onerous duties ; 

 (2) by the continual growth of what may be termed the 

 ordinary items of expenditure ; and (3) by the failure of 

 Whitehall to contribute a fair share of the total burden 

 of the increasing cost. The development of our educational 

 system, which has advanced enormously during the last 

 six years, has also entailed a large annual increment to 

 the rates ; and, apart from what has already been accom- 

 plished, there are still many urgent educational reforms 

 which would doubtless be undertaken by local authorities 

 if it were not for the reluctance of Whitehall to bear a 

 fair share of the cost involved in carrying out the improve- 

 ments. .Among these reforms may be placed : — (il the re- 

 duction in the size of the classes ; and (2) the replacement 

 of supplementary teachers by certificated teachers. The 

 Government grant in support of national elementary educa- 

 tion is totally inadequate. In conclusion, Mr. .Adams 

 emphasised the fact that the exiguous grant given by the 

 State to the local universities, which have now become 

 an indispensable part of our educational system, is not 

 creditable to a wealthv and progressive nation like ours. 

 The outcry heard against the growing burden of the cost 

 of education is not the expression of a spirit of grant- 

 greed, but represents a fear that through inadequate 

 Ciovernment support the schools may send forth scholars 

 who will not be equipped properly for the warfare of life 

 or for taking their part in the struggle which has to be 

 made unceasingly for the maintenance of the commercial 

 and industrial position of our nation. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society. November 12, 190S. — "The Occlusion 

 of the Residual Gas and the Fluorescence of the Glass 

 Walls of Crookes Tubes." By .Alan .A. Campbell Swinton. 

 Communicated by Sir William Crookes, F.R.S. 



In a previous paper ' the writer has described experi- 

 ments indicating that the occlusion of the gas is due to 

 its being driven into the glass, in which it forms bubbles 

 on subsequent heating. 



The present paper deals with Mr. Robert Pohl's sugges- 

 tion that the bubbles are not due to the gas at all, but to 

 chemical action on the glass, when heated, of aluminium 

 disintegrated from the electrodes. 



The author finds that after prolonged sparking por'tions 

 of the internal surface of the glass of tubes with external 

 electrodes consisting of caps of tinfoil show numerous but 

 very small bubbles when heated. This, as it would seem, 

 entirely disposes of Mr. Pohl's contention. 



The electric discharges passed through the tubes were 

 so weak that the heating of the glass was very slight. 

 The temperature cannot thus have been sufTiciently raised 

 either to allow of the gas passing into the glass by 

 ordinary, diffusion, as suggested by Sir J. J. Thomson, or 



1 "The Occlusion of the Residual Gas by the Glass Walls of Vacuum 

 Tubes," Roy. Soc. Proc , A, vol. Ixxix., pp. 134-7. 



of the gas being evolved inside the glass by chemical de- 

 composition due to heat, as put forward by Mr. Soddy and 

 Mr. Mackenzie. 



Grinding away the glass to the extent just necessary to 

 prevent the formation of bubbles on subsequent heating 

 also showed that the depth to which the gas is driven into 

 the glass varied from 0-0025 mm. for tubes with external 

 electrodes to as much as 0-015 mm. with internal elec- 

 trodes, the distances being in all cases considerably less — 

 about one-tenth — than the distances between the surface 

 of the glass and the centres of the bubbles produced by 

 subsequent heating. 



By means of a fluorescent screen placed behind a patch- 

 work screen of different thicknesses of aluminium foil, it 

 was ascertained that the ma.ximum thickness of aluminium 

 through which kathode rays will pass is about 0-014 mm., 

 which agrees very fairly with the above-mentioned figure 

 of 0-015 mm. 



Thus neither the explanation of Sir J. J. Thomson nor 

 that of Mr. Soddy and Mr. Mackenzie seem necessary, 

 for the gas in the first instance travels into the glass only 

 about the same distance that kathode rays penetrate into 

 aluminium, and it is therefore reasonable to suppose that 

 the gas is driven in mechanically according to the writer's 

 original contention. Diffusion, however, probably takes 

 place when the glass is softened in the flame, when the gas 

 penetrates further and forms bubbles on cooling, in much 

 the same way that air bubbles are formed in ice. 



Experiments were also made on the fatigue of the glass 

 in respect to fluorescence. Except in cases where this 

 fatigue was due to deposits of electrode matter or of 

 carbon, it was found necessary, in order to do away with 

 it, to grind away a thickness of glass approximately the 

 same as had to be removed to prevent the formation of 

 bubbles on subsequent heating. It would therefore appear 

 that fatigue is intimately connected with, and is perhaps 

 the direct result of, the penetration and presence of the 

 occluded gas. That part of this fatigue is very permanent 

 is shown by a tube in the author's possession, which still 

 shows fatigue due to bombardment it received in 189S. 

 Though part of the fatigue is permanent, most of it is 

 but temporary. This may be due to the gradual escape 

 of such portion of the gas as has been driven into the 

 glass onlv such a very short distance that the latter is 

 unable permanently to retain it. 



Paris. 

 Academy of Sciences, December 2?, 1908. — M. Bouchard 

 in the chair. — The lava of the last eruptions of \'ulcano, 

 Eolian Isles : A. Lacroix. In the cases of Mt. Pel^e, 

 Vesuvius, and Etna it has been proved that in a given 

 eruption any changes in the chemical composition of the 

 lava are very slight, and are not systematic. Observa- 

 tions published by various authors on the products of the 

 last eruption of Vulcano appear to lead to different con- 

 clusions. Various specimens of the lava from this erup- 

 tion have been analysed, and the existence of such marked 

 differences is not confirmed. — Some properties of the tubercle 

 bacillus cultivated on bile : H. Calmette and C. Guerin. 

 The authors are convinced that experiments in tuberculosis 

 in which cultures in glycerol, gelatin, potato, or broth 

 are used give different results from those of natural in- 

 fection. They have found that the bacillus grows per- 

 fectly on pure bile with 5 per cent, of glycerin and 

 sterilised, and after several successive cultures on this 

 medium it acquires very distinct physiological characters. 

 Full details are given of the mode of working and of the 

 appearance and properties of the bacillus thus obtained. 

 It is easily absorbed through the wall of the digestive tube, 

 and when it has penetrated in sufficient quantity in this 

 way it can create lesions with rapid calcification such as 

 could never be obtained experimentally with cultures in 

 ordinary glycerin media. — M. Villard was elected a 

 member in the section of physics In the place of the late 

 E. Mascart. — Concerning the distribution of the aphelia 

 of the minor planets : hmile Belot. .A diagram is given 

 of the distribution. — The use of coloured screens and 

 orthochromatic plates for the photographic observation of 

 the fixed stars : CEsten Bergstrand. The combination of 

 a yellow screen and an orthochromatic plate produces much 

 greater clearness in the images, and also eliminates the 



NO. 2045, VOL. 79] 



