CONTENTS. 

 VOL. LXVII. 



No. 435 



Page 



Meeting of June 21, 1900, and List of Papers read 1 



Investigations on Platinum Thermometry at Kew Observatory. By 

 C. Chree, Sc.D., LL.D., F.E.S., Superintendent. Communicated by 

 the Kew Observatory Committee 3 



A Comparative Crystallographical Study of the Double Selenates of 

 the Series E 2 M(SeO 4 )o,6H 2 O. -Salts in which M is Zinc. By A. E. 

 Tutton, B.Sc., F.E.S 58 



No. 436. 



Certain Laws of Variation. I. The Reaction of "Developing Organisms 

 to Environment. By H. M. Vernon, M.A., M.D., Fellow of Mag- 

 dalen College, Oxford. Communicated by Professor E. Eay Lan- 

 kester, F.E.S 85 



On the Diffusion of Gold in Solid Lead at the Ordinary Temperature. 

 By Sir W. Eoberts- Austen, K.C.B., F.E.S., Professor of Metallurgy, 

 Eoyal College of Science 101 



On Certain Properties of the Alloys of the Gold- Copper Series. By 

 Professor Sir W. Eoberts-Austen, K.C.B., F.E.S., and T. Kirke 

 Eose, D.Sc. (Plate 1) 105 



The Crystalline Structure of Metals. Second Paper. By J. A. Ewing, 

 F.E.S., Professor of Mechanism and Applied Mechanics in the 

 University of Cambridge, and Walter Bosenhain, B.A., St. John's 

 College, Cambridge, 1851 Exhibition Eesearch Scholar, Melbourne 

 University 112 



On the Estimation of the Luminosity of Coloured Surfaces used for 

 Colour Discs. By Sir William de W. Abney, K.C.B., F.E.S 118 



The Diffusion of Ions produced in Air by the Action of a Eadio-active 

 Substance, Ultra-violet Light, and Point Discharges. By John S. 

 Townsend, M.A., Clerk Maxwell Student, Cavenish Laboratory, 

 Fellow of Trinity College, Cambridge. Communicated by Professor 

 J. J. Thomson, F.E.S 122 



Static Diffusion of Gases and Liquids in Eelation to the Assimilation 

 of Carbon and Translocation in Plants. By Horace T. Brown, F.E.S., 

 LL.D., and F. Escombe, B.Sc., F.L.S 124 



