yA TURE 



[January 30, 1908 



\ 



A SCHEME to prepare girls better to undertake the duties 

 of the home was described in a letter to the Times of 

 January 24. The communication was signed by Prof. 

 William Osier, F.R.S., Sir Henry Roscoe, F.R.S., and 

 Prof. A. Smithells, F.R.S., with others. Instruction of 

 the kind required is impossible without teachers capable 

 of giving it, and the first step must be, the letter points 

 out, to provide education of an advanced type for those 

 who will hereafter conduct the work in its more elementary 

 stages. It is therefore proposed to provide in London a 

 course of post-graduate instruction in household economics. 

 The course will be given at the women's department of 

 King's College, and will begin next October. A college 

 board, consisting mainly of the professors of the subjects 

 germane to the course', with Prof. Smithells acting as 

 honorary adviser, will control the educational side of the 

 work. It is hoped that it will be found possible to include 

 courses of training for the management of large educa- 

 tional and other institutions, for the duties of factory in- 

 spection, and for social work aimed at raising the standard 

 of home life. Donations are asked for in order to raise 

 3000!., the sum necessary for the effective organisation of 

 the scheme, and may be sent to Miss Soltau, King's 

 College (Women's Department), 13 Kensington Square, W. 



The best results are obtained in those technical schools 

 where the students are encouraged to follow a suitable 

 course of training extending over a number of years, and 

 where the instruction provided is suited exactly to the 

 industrial requirements of the district. The late'st report 

 of the Board of Education states in this connection : — 

 " Well-considered programmes of instruction within schools 

 and careful adjustment of the relation of school to school 

 in populous areas have become more common. In an 

 increased number of schools we find teachers at pains to 

 urge continuity of study and to order their teaching so as 

 to help towards this end. Opportunities for advanced 

 work are provided more widelv than before, and accord- 

 ingly we find the period of study extending and the number 

 of students of mature years increasing." To mark still 

 more obviously the importance of continuitv of study, the 

 Board has given prominence to an arrangement by which 

 the Board and the school authorities join in responsibility 

 for the issue of " technical course certificates " affording 

 suitable records of completed curricula. These certificates 

 are to be given only in connection with courses each 

 approved as providing such a technical education as will 

 have a definite value in relation to the occupation to which 

 it has regard. Each certificate as awarded bv the local 

 education authority or the managers of a school and 

 endorsed by the Board will record continued attendance 

 and satisfactory attainments in the several sections of the 

 specified course of instruction. The svstem thus initiated 

 appears to be capable of considerable development. It 

 mav become a valuable feature in the organisation of 

 technical courses— standardising their aims and encouraging 

 the students to persistent attendance and continuitv of study. 

 The statistics in connection with the examination of 

 students in evening schools, too, the report points out, 

 reflect both the improvement in the provision of more 

 advanced classes and the increased regularity of the attend- 

 ance of the students. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society. November 7. 1907. — "The Electrical 

 Discharge in Monatomic Gases." Bv F. Soddy and 

 T. D. Mackenzie. Communicated by Prof. J. Larmor, 

 Sec.R.S. 



Helium and argon purified bv volatilising calcium 

 (Soddy, Proc. Roy. Soc, iqo?, Ixxviil., A, 429) from traces 

 of common gases show a disinclination to conduct the dis- 

 charge, and the question arises whether the monatomic 

 gases in a perfectly pure state will conduct at all. The 

 well-known phenomenon of " running out " or exhaustion 

 of spectrum tubes filled with these gases with prolonged 

 use might be due to absorption of the Impurities only by 

 the electrodes leaving the pure monatomic gases i'n a 

 non-conducting state. This question has been exhaustively 

 investigated, and the conclusion is drawn that the mon- 

 NO. IQ96, VOL. 77I 



atomic gases conduct in the same manner as common 

 gases, but are relatively electrically, as well as chemically, 

 inert. That is to say, the various stages of the discharge 

 from the X-ray vacuum to the ribbon discharge when 

 considerable quantities of gas are present are produced in 

 the case of helium, for e.xample, at pressures from five to 

 ten times the pressure required to produce the same stage 

 of the discharge In a gas like hydrogen or nitrogen. 



The " running out " of spectrum tubes filled with mon- 

 atomic gases under the discharge is due to absorption of 

 the monatomic gas principally In the film of aluminium 

 volatilised from the electrodes. In one series of experi- 

 ments six tubes were filled with helium purified by calcium 

 at the initial pressures i-i mm., 2-3 mm., 4-9 mm., 

 8.6 mm., 16-8 mm., and 31.2 mm. The first three became 

 non-conducting — the discharge passing an alternative spark 

 gap of an inch of air, and the tube fluorescing strongly 

 — with less than an hour's running, and the fourth after 

 sixty hours, the residual pressure of pure helium in 

 each case being about 0-7 mm. This was determined 

 by breaking the tube under mercury, and confirmed 

 by the use of a specially designed form of McLeod 

 gauge. In the first case the mercury rapidly liberated 

 the greater part of the occluded gas by dissolving the film 

 of volatilised aluminium. The occluded gases are al=o 

 slowly evolved spontaneously In the cold, and practlcaiiv 

 completely when the tube is heated to its softening point 

 for some time. 



X-rays are given out in pure helium at pressures below 

 0-2 mm. in an X-ray tube 8 cm. diameter, while in 

 hydrogen X-rays are not given out until the pressure is 

 reduced below o-i mm. It is probable that the real 

 pressure in an X-ray tube is in no case belov.- '^-ni mm., 

 and the general impression that the pressure is of the order 

 of o-ooi mm. Is due to a variety of misapprehensions re- 

 garding high vacua. The behaviour of argon, neon, 

 mercury vapour, nitrogen, and carbon dioxide has also 

 been investigated. 



The behaviour of helium at low pressures, at which it 

 conducts the discharge with abnormal difficulty, is strictly 

 analogous to its behaviour at high pressures, when it con- 

 ducts with abnormal facility (Ramsay and Collie, Proc. 

 Roy. Soc, 1896, lix., p. 257). The curves connecting dis- 

 charge potential and pressure were taken in the same tube 

 for helium and hydrogen. Helium at 60 mm. showed the 

 same discharge potential (7750 volts) as hydrogen at 

 12 mm. At a pressure of 30 mm. the potential in helium 

 was 3400 volts, and In hydrogen 16,000 volts. Through- 

 out the whole region, both of high and low pressure, one 

 hydrogen molecule is electrically equivalent, so far as its 

 effect on the character of the discharge Is concerned, to 

 several helium molecules. 



The remarkable observation was made that some new 

 spectrum tubes, as obtained from the maker, generated 

 helium during preparation and the removal of the occluded 

 gases. The only escape from the conclusion that helium 

 was formed under the special conditions to which the 

 tubes had been subjected was that the helium was derived 

 from the aluminium electrodes. Experiments were made 

 with old aluminium electrodes which had been exposed for 

 months to the air after removal from old spectrum tubes 

 in which they had been used with the rare gases. By the 

 help of the calcium method it was proved that helium, 

 neon, and argon can be obtained in this way in quantities 

 sufficient to give a clear spectrum from old aluminium 

 electrodes which have been used with these gases. 



."Ml the spectrum tubes use'd showed strongly Campbell 

 Swinton's effect (Proc. Roy. Soc, 1907, A, vol. Ixxix., 

 p. 134) of developing minute bubbles when fused, usually 

 in the areas exposed to the bombardment of particles 

 travelling normally from the surface of the electrodes ; but 

 the argon tubes showed the effect to an extraordinary 

 extent, the glass appearing to boil when fused. Experi- 

 ments are described in which these glasses have been sub- 

 jected to a temperature of 1300° C. in a vacuum furnace, 

 and all but the inert gases absorbed by calcium. Only 

 the minutest trace of rare gas is ever obtained in this 

 way, and this is quite insufficient to produce the effect. 

 In the case of the glass of a helium tube which showed 

 Campbell Swinton's effect strongly, it was proved that 

 after a preliminary heating in a vacuum, at a temperature 

 below that necessary to produce bubbles, to drive off surface 



