PROCEEDINGS OF 

 THE ROYAL SOCIETY. 



VOL. XV. No. 90. 



] CONTENTS. 



Fehruary 7, 1867. 



PAGE 



Account of Experiments on Torsion and Flexure for the Determination of 



Eigidities. By J. D. Eveeett, D.C.L 356 



February 14, 1867. 



I. On the Relation of Insolation to Atmospheric Humidity. By J. Park 

 Haeeison, M.A 356 



II. On the Conversion of Dynamical into Electrical Force without the aid of 



Permanent Magnetism. By C. W. Siemens, F.E.S 367 



III. On the Augmentation of the Power of a Magnet by the reaction thereon of 



Currents induced by the Magnet itself. By Chaeles Wheatstone, F.R.S. 369 



Fehruary 21, 1867. 



A brief Account of the ' Thesaurus Siluricus,' with a few facts and inferences. 

 By J. J. BiGSBY, M.D 372 



Fehruary 28, 1867. 



I. On a Transit-Instrimaent and a Zenith Sector, to be used on the Oreat Tri- 

 gonometrical Survey of India for the determination, respectively, of Longi- 

 tude and Latitude. By Lieut.-Colonel A. Steange, F.E.S 385 



II. On the Orders and Genera of Ternary Quadratic Forms. By ITenet J. 



Stephen Smith, M.A., F.E.S 387 



TAYLOE AND FRAIS^CIS, EED LION COUET, FLEET STEEET. 



