.10- 



NATURE 



[January 9, 19 13 



on the move in matter, and are the carriers of heat 

 and electricity. Wliether it still undergoes trans- 

 formations is a question we may well ask; I will 

 consider it very briefly in a few minutes. 



Transformation in either direction can only take 

 place during- the traverse of an atom. The atom 

 is the transforming agent, but atoms differ in their 

 transforming power. Usually the heavier the atom 

 the more apt it is to bring about the transformation 

 in an X-ray which tries to cross it, but there are 

 regular exceptions. Every atom possesses one or 

 more critical energy quantities ; if the energy of the 

 X-ray exceeds the critical value of the atom it is much 

 more likely to undergo transformation than if it falls 

 short. The critical values grow with the atomic 

 weights, and are on the whole nearly proportional 

 to the squares of the latter. Thus the critical energy 

 of the zinc atom is about i'75 x lo-* ergs, of the 

 nickel atom about i'67Xio-^ ergs. An X-ray, having 

 an energy less than both these, is absorbed or trans- 

 formed rather more readily by zinc than bv nickel, but 

 an X-ray having an energy greater than the lower 

 but not greater than the higher (e.g. the X-rav given 

 off by zinc when irradiated by sufficiently penetrating 

 primary X-rays, and now Icnown as the Zn X-rav) is 

 actually much more readily transformed by the nicliel 

 than by the zinc. 



Moreover, I believe this to be capable of extension. 

 It is not only the X-ray that must possess energv 

 greater than the critical value of the atom if trans- 

 formation is to take place readily, but also a rav 

 must possess energy above the same limit if it is 

 to be turned readily into an X-ray. Consequently a 

 /3 ray is more apt to disappear if its energy exceeds 

 the limit than if it falls short, and a stream of (3 rays 

 seems actually to have less penetration than it would 

 have if the individual rays were moving more slowlv. 

 I think I am in a position to show this as the result 

 of recent experiment ; I have found it to be so in the 

 few cases I have tried, but there are very few cases 

 which it is possible to try. 



{To he continued.) 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Mill Hill School has recently received a gift of 

 5000L from Mrs. Richardson, one of the nieces of the 

 late Lord Winterstoke, formerly chairman of the 

 governors of the school. 



Major Sir Ronald Ross. K.C.B., F.R.S., formerly 

 professor of tropical medicine, University of Liver- 

 pool, is now professor of tropical sanitation, L'niver- 

 sity of Liverpool, lecturer on malaria, Liverpool School 

 of Tropical Medicine, and physician for tropical 

 diseases. King's College Hospital, London. 



The Rev. John H. Ellis, who died in November 

 last, has left, subject to his widow's life interest, the 

 residue of his property, which will amount to at least 

 t)o,ooo/., to "the L'niversity of Cambridge to be 

 enjoved and applied both as to capital and income by 

 them for the general purposes of the University in 

 such manner as they may think lit." 



The December issue of The Reading University 

 College Review, in addition to its very interesting 

 notes summarising the work recently accomplished 

 at the college, contains an article explaining the 

 general idea of the scheme of new buildings which 

 the council of the University College at Reading pro- 

 jtnses to carry out upon the main site. Another 

 .".rticle, bv Mr. J- P- Clatworthv, lecturer in mathe- 

 matics at the college, deals with mathematics and the 

 liMilogical sciences. 



NO. 2254, VOL. goj 



The danger of over-specialisation in higlier educa- 

 tion forms the keynote of a paper on the functions of 

 the American college, by Prof. A. K. Rogers, in The 

 Popular Science Monthly for December. As the 

 author points out, there is a constant tendency among 

 college teachers to cater more and more for the 

 specialist in their own particular study, wliereas if 

 the college is to maintain its influence, it should 

 rather aim at broadening the minds of the large 

 majority of students of average ability. The author 

 remarks that " the exceptional man is pretty apt to 

 look out for himself. He will thrive probably in spite 

 of our attempts to educate him quite as much as 

 because of them." 



The President of the Board of Education has 

 decided to appoint an advisory council for the Victoria 

 and Albert Museum. The following persons have already 

 consented to serve : — The Right Hon. Lord Reay 

 (chairman), Mr. R. H. Benson, Mr. R. Blomfield, 

 Sir Edward T. Cook, Mr. J. H. Fitzhenry, Mr. R. E. 

 Frv, Mr. Frank Green, Lady Horner, Mr. Elijah 

 Howarth, the Earl of Lytton, the Countess of Ply- 

 mouth, Sir Isidore Spielmann, C.M.G. The council 

 will be asked to advise the Board on questions of 

 principle and policy arising from time to time, and 

 to make an annual report on their proceedings to 

 the Board, together with any observations on the 

 condition and needs of the museum which they may 

 think fit to make. It will be open to the council to 

 constitute subcommittees on which persons who are 

 specially qualified to advise on particular questions 

 referred to the council may be invited by the Board, 

 to serve in addition to the ordinary members of the' 

 council. 



The fourteenth of a series of articles which has 

 been appearing in the Journal of the Department of 

 Agricultural and Technical Instruction for Ireland has 

 now been issued in pamphlet form. It is written by 

 Mr. T. Clearkin, and is concerned with technical in- 

 struction in Larne. Larne differs from many small 

 towns of Ireland, as it has various flourishing indus- 

 tries giving constant employment to a considerable 

 number of skilled workers — men and women. Many 

 of these industries have grown up within the last 

 twenty years, e.g. the manufacture of aluminium, 

 linen-weaving, and paper-making. The shipping in- 

 dustry, too, is of some importance, and the engineer- 

 ing and building trades give employment to a fair 

 number of apprentices. The object of the municipal 

 technical school which has now been established in 

 Larne is to instruct in the scientific and artistic know- 

 ledge necessary for a thorough understanding of the 

 several callings in which the inhabitants are already 

 engaged. 



The scheme of the competitive examination, held 

 under the direction of the Civil Service Commis- 

 sioners, for admission to the Indian Police Force is 

 to be modified, by requiring candidates to take up 

 English history and geography as a compulsory sub- 

 ject. The change will come into operation for the 

 examination of 1914. There will then be four obliga- 

 tory subjects which must be taken by all candidates, 

 viz. English, elementary mathematics, French or Ger- 

 man, and English history and geography. There are 

 six optional subjects, of which candidates may take 

 two; but, if one of the subjects selected is a modern 

 language, it must be different from that taken as an 

 obligatory subject. The optional subjects are inter- 

 mediate mathematics, higher mathematics, German 

 or French, Latin, Greek, and science (physics and 

 chemistry). In addition, candidates may take up free- 

 hand drawing. The maximum mark obtainable is 

 the same for all subjects, except free-hand drawing. 



