May 23, 1918] 



NATURE 



in this way to any waves shorter than those of the red — 

 that is, they respond throughout practically the- whole 



visible spectrum as well 



IS th< 



ultra-violet spectrum. 

 were therefore placed 



of appa 



volts and the frequency of the light, and it also de- 

 mands that the slope of this line should be exactly 

 equal to hje. Hence from this slope, since e is known, 

 it should be possible to obtain h. How perfect 

 a linear relation is found may be seen 

 from Fig. 5, whicli also shows lli.il from tlic 

 slope of this iinr li is tound lo 1m' t)-5*>x 10 -', 

 which is as close to the value obtained b_v 

 Planck from the radiation laws as is to be 

 expected from the accuracy with which the 

 experiments in radiation can be made. The 

 most trustworthy value of h obtained from a 

 consideration of the whole of this work is 

 ^:=6-56x 10-^'. In the original paper will be 

 found other tests of the Kinstein equation, but 

 the net result of all this work is to confirm in 

 a very complete way the equation which Ein- 

 stein first set up on the basis of his semi- 

 oorpuscular theory of radiant energy. And if 

 this equation is of general validity it must 

 certainly be regarded as one of the most 

 fundamental and far-reaching of the equa- 

 tions ot ph\sics, and one which is destined 

 to plav in the future a scarcely less impor- 

 tant role than Maxwell's equations have 

 played in the p^^st, for it must govern the 

 transformation of all short-wave-length 

 electromagnetic energy into heat energy. 

 {To he continued.) 



on the wheel W (Fig. 4), and fresh, clean surfaces were 

 obtained by cutting shavings from each metal in an 

 excellent vacuum with the aid of the knife K, which 

 was operated by an electromagnet F outside the tube. 

 After this the freshly cut surface was turned 

 around by another electromagnet until it was 

 opposite the point O of Fig. 4, and a beam of mono- 

 chromatic light from a spectrometer was let in through 

 O and allowed to fall on the new surface. The energy 

 of the electrons ejected by it was measured by applying 

 to the surface a positive potential just strong enough 

 to prevent any of the discharged electrons from reach- 

 ing the gauze cylinder opposite (shown in dotted lines) 

 and thus communicating an observable negative charge 

 to the quadrant electrometer which was attached to this 

 gauze cylinder. For a complete test of the equation 

 it was necessary also to measure the contact-electro- 

 motive force between the new surface and a test plate 

 S. This was done by another electromagnetic device 



FREQUENCY 



-Oraph showing lelaiioii 

 frequency of the light 



hetween energy of electric emission .inJ 

 hich stimulates the emission. 



shown in Fig. 3, but for further details the original 

 paper may be consulted (see Phys. Rev., vol. vii. [1916], 

 p. 362). Suffice it here to say that Einstein's equation 

 demands a linear relation between the applied positive 

 NO. 2534, VOL. lOl] 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



LoNUO.N.— The thanks of the Senate have been 

 accorded to the Worshipful Company of Drapers for 

 the renewal, at the rate of 300/. a year for 19 iS iind 

 1919, of their grant in aid of the biometric labora- 

 tories of the department of applied statistics at Liii- 

 versity College ; and to the Chadwick trustees for the 

 renewal of their grant of 250^. in furtherance of the 

 promotion of sanitary science by aiding the mainten- 

 ance of the Chadwick professorship of hygiene and 

 the teaching of municipal engineering at University 

 College during the year 1918-19, and for their con- 

 tinued provision of the Chadwick gold medal. 



The Senate has adopted a resolution expressing 

 gratification that the London Hospital has decided 

 to open its medical college to women students — " a 

 step which is in entire conformity both with the 

 wishes and the policy of the University." 



The following doctorates have been conferred : — 

 D.Sc. in .Statistics: Mr. R. J. Ewart, an internal 

 student, of the Lister Institute of Preventive Medi- 

 cine, for a thesis entitled "The Influence of Age of 

 Parent at Birth on Length of Life, Sex, Suscepti- 

 bility to Zymotic Diseases, Stature, Intelligence, and 

 Eye-colour." D.Sc. in Botany: Mr. Walter Watson, 

 an external student, for a thesis entitled " The Bryo- 

 phytes and Lichens of Various Ecological Groups of 

 Vegetation," and other papers. D.Sc. in Physics .- 

 Mr. E. N. da Costa .^ndrade^ an external ^-tudi nt. fi.i 

 a thesis entitled "The Flow of Metals under ( un- 

 stant Stresses." and other [iajiers. 



The remaining public lectures of iii< (.>nis. imi 

 "Some Biological Problems of T()-da\ '" will he dt - 

 livered at University College, London (Gower Street, 

 W.C.i), on Mondavs at 5; p.m., as follows: — May 27, 

 "Substitution of Raw Materials," by Prof. F. W. 

 Oliver; June 3, rh« .\naerobic Treatment of 

 Wounds," bv Dr. R . ( . .McLean; and Tune to, 

 • l-resh Air a'nd h.irui.ncv.- in Prof. M. R. Kinv.ood, 



