i84 SCIENCE PROGRESS 



Young, R. K., The Spectroscopic Binary, 12 Lacertae, Pub. Dom. Astroph. 



Obs., 1, No. 2. Orbit of the Spectroscopic Binary, Boss 4669, ibid., 1, 



No. 6. 

 Harper, W. E., Orbit of the Spectroscopic Binary, Boss 4507, ibid., 1, No. 5. 



Orbit of the Spectroscopic Binary, t Delphini, ibid., 1, No. 8. 

 Plaskett, J. S., Description of Building and Equipment, ibid., 1, No. i. The 



Spectroscopic Binary, H. R. 8170, ibid., 1, No. 3. 

 Turner, H. H., On the Suggested Increase in Period of Variable Stars in 



Phillips' Group, i M.N., R.A.S., 80, 481, 1920. 

 Plummer, H. C, On the Nature of Short-Period Variables, M.N., R.A.S., 



80, 496, 1920. 

 Shapley, H., and Davis, Helen M., Studies Based on the Colours and Mag- 

 nitudes in Stellar Clusters : XVI, Photometric Catalogue of 848 Stars 



in Messier 3, Astroph, Journ., 51, 140, 1920. 

 Jackson, J., The Orbits of Twenty Double Stars, M.N., R.A.S., 80, 543, 



1920. 

 Becker, L., The Capture Hypothesis of Binary Stars, M.N., R.A.S., 80, 



598, 1920. 



Oppenheim, S., Uber die Eigenbewegungen der Fixsterne : 



I. Kritik der Zweischwarmhypothese, 191 1. 

 II. Entwicklung nach Kugelfunctionen, 19 15. 



III, Kritik der Ellipsoidhypothese, 1916. 



IV. Das Verteilungsgesetz der Eigenbewegungen, 1919 (A. Holder, 

 Vienna) . 



Statistike Untersuchungen fiber die bewegungen der kleinen Planeten, 

 1919 (A. Holder, Vienna). 



Malmquist, K. G., a Study of the Stars of Spectral Type A, Medd. Lunds 

 Ast. Obs., Ser. II, No. 22, 1920. 



Sampson, R. A., Determination of Longitude by Wireless Telegraphy, M.N., 



R.A.S.^%0, 659, 1920. 

 Ferri^ (General), Note sur les Proc6d6s actuels d'Emploi de la T.S.F. 



dans la Determination des Longitudes, M.N., R.A .S., 80, 669, 1920. 



Nagaoka, H., Diffraction of a Telescope Objective in the Case of a Circulair 



Source of Light, Astroph. Journ., 51, 73, 1920. 

 Ingersoll, L. R., Polarisation of Radiation by Gratings, Astroph. Journ., 



51, 129, 1920. 

 Hamy, M., Sur un cas de diffraction des images des astres circulaires, C.R., 



169, 822, 1919 ; Sur un cas particulier de diffraction des images des 



astres circulaires de grands diam^tres, C.R., 170, 1143, 1920. 

 MiCHELSON, A. A., Sur I'application des m^thodes interf^rentielles aux 



m6sures astronomiques, C.R., 171, 15. 1920. 



PHYSICS. By D. Orson Wood, M.Sc, University College, London. 



The Bakerian Lecture this year was delivered by Sir Ernest 

 Rutherford, who, speaking on " The Nuclear Constitution of 

 Atoms," gave an account of the latest developments of his work 

 on the intense bombardment of light atoms by swift a-rays 

 {Proc. Roy. Soc, 1920, A97, 374-401 ; an account of the earlier 

 work appeared in the Phil. Mag., 191 9, 37, 538, and was dealt 

 with in Science Progress, 1919, 54, 206-11). It will be 

 remembered that, when a-rays from radium C are allowed to 

 pass through nitrogen, swift particles are obtained which. 



