PEOCEEDINGS OF 

 THE ROYAL SOCIETY. 



VOL. lxv. No. 421. 



Smithso ttian Institution. 



CONTENTS. 



PAGE 



Collimator Magnets and the Determination of the Earth's Horizontal Mag- 

 netic Force. By C. Cheee, Sc.D., LL.D ., F.R.S., Superintendent of the 

 Kew Observatory. Communicated by the Kew Obseevatoey Com- 

 mittee of the Royal Society 375 



The Absorption of Rontgen's Rays by Aqueous Solutions of Metallic Salts. 

 By the Right Honourable Lord Blythswood, LL.D., and E. W. 

 Maechant, D.Sc. Communicated by Loed Kelvin, F.R.S. . . . 413 



On the Resistance to Torsion of certain Forms of Shafting, with special Refer- 

 once to the Effect of Key ways. By L. N G-. Filon, M.A.. Research 

 Student of King's College, Cambridge, Fellow of University College, 

 London, 1851 Exhibition Science Research Scholar .... 428 



Price Two Shillings, 



November 30 , 1899. 



