540 SCIENCE PROGRESS 



Raman, of the University of Calcutta, and his pupils to 

 undertake a systematic study of this field. Two papers have 

 already appeared in the P.R.S. for last April and November, 

 and a comprehensive outline of the present state of the subject 

 is given in a small monograph by Professor Raman, " Molecular 

 Diffraction of Light," published recently by the Calcutta Uni- 

 versity Press. In this monograph Raman advances the view 

 that the partial breakdown of the Einstein-Smoluchowski 

 formula is due to the inadequacy of the Maxwell equations of 

 the electromagnetic field when applied to emission or absorption 

 of energy from atoms or molecules. He suggests that these 

 phenomena may yield some support to the very revolutionary 

 form of the Quantum hypothesis put forward by Einstein 

 (going considerably beyond Planck's own conservative views) 

 that the energy of a beam of light is not distributed continu- 

 ously in space, but consists of a finite number of localised in- 

 divisible energy-bundles or " quanta " capable of being absorbed 

 or emitted only as wholes.^ It must be said that the model 

 introduced by Bohr for the atom, with its stationary states, is 

 more in accord with this view of both discontinuous absorption 

 and emission, than with Planck's reservation concerning con- 

 tinuous absorption, which was actually introduced by him so 

 as to accommodate his special form of the Quantum hypothesis 

 to the Maxwell equations. 



PHYSICAL CHEMISTBY. By W. E. Garner, M.Sc, University 

 College, London. 



A New Element. — The search for missing elements has been 

 rewarded by a number of discoveries, based on spectroscopic and 

 X-ray evidence, which make it probable that the number of 

 vacant places in the periodic table will be considerably dimin- 

 ished in the near future. The number of elements with an 

 atomic weight less than that of uranium, which remain to be 

 discovered, is Hmited to those with the atomic numbers 43, 

 61, 72, 75, 85, and 87. There now appears no doubt as to 

 the existence of an element, between lutecium and tantalum, 

 with the atomic number 72. Dauvillier {C.R., 1922, 174, 

 1347-9), and Hevesy and Coster {Nature, 1923, 111, 79) 

 claim to have demonstrated the existence of an element with 

 this atomic number. The material in which the new element 

 was detected was very different in the two cases ; the former 

 made use of a rare earth preparation of Urbain's, and the 

 latter made their discovery with a zirconium mineral. 



Urbain {C.R., 191 1, 152, 141-3), during the fractionation of 



* As is well known, J. J. Thomson entertains views of a similar nature as 

 to the propagation of light. 



