vii 



Page 



On the Orientation of Greek Temples, being the results of some 

 Observations taken in Greece and Sicily in the month of May, 1898. 

 Bv F. C. Penrose, M.A., F.R.S., F.R.I.B.A., &c 370 



No. 421. 



Collimator Magnets and the Determination of the Earth's Horizontal 

 Magnetic Force. By C. Chree, Se.D., LL.D., F.R.S., Superintendent 

 of the Kew Observatory. Communicated by the Kew Observatory 

 Committee 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. Marchant, D.Sc. Communicated by Lord Kelvin, F.R.S 413 



On the Resistance to Torsion of Certain Forms of Shafting, with 

 special Reference to the Effect of Keyways. 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 



No. 422. 



Meeting of November 16, and List of Papers read 432 



Note on the Electromotive Force of the Organ Shock and the Elec- 

 trical Resistance of the Organ in Malapterurus electricus. Bv Francis 

 Gotch, M.A., F.R.S.. and G. J. Burch, M.A. Oxon 134 



On the Formation of the Pelvic Plexus, w ith especial Reference to the 

 Nervus Collector, in the Genus Mustelus. By R. C. Punnett, B.A., 

 Scholar of Gonville and Caius College, Cambridge. Communicated 

 by Hans Gadow, F.R.S 445 



On the Least Potential Difference required to produce Discharg'' 

 through various Gases. By the Hon. R. J. Strutt, B.A., Scholar of 

 Trinity College, Cambridge. Communicated by Lord Rayleigh, 

 F.R.S ! 446 



Meeting of November 23, 1899, and List of Ollicers and Council 

 nominated for Election 448 



List of Papers read 449 



Note on the Spectrum of Silicium. By Sir Norman Lockyer, K.C.B., 

 F.R.S 449 



Preliminary Table of Wave-lengths of Enhanced Lines. By Sir 

 Norman Lockyer, K.C.B., F.R.S 452 



The Colour-Physiology of Hippolyle varians. By F. W. Keeble, Caius 

 College, Cambridge, and F. W. Gamble, Owens College, Manchester. 

 Communicated b}^ Professor S. J. Hickson, F.R.S 461 



An Experimental Research on some Standards of Light. By J. E. 

 PetaveL Communicated by Lord Rayleigh, F.R.S ........... 469 



