142 Royal Society : Mr. Macleans further particulars 



following diameters common : l-6000th, l-5SOOth, l-5332d, 

 l-5000th, l-4924th, and l-4800tb. Extreme sizes 1 -6400th 

 and l-4000th of an inch. 



Blood from a vein of the ear, also from a prick of the velvet 

 of the young growing antler. The corpuscles obtained from 

 these different parts were identical in size and appearance. 



A recent examination of the blood corpuscles of some va- 

 rieties of the common sheep (42.) gave the following results. 



a. A four-horned Sheep from North Africa. 



b. A two-horned hairy variety from Africa, presented to 

 the Zoological Society by the Duke of Sutherland. 



c. A hairy variety from Demerara. 



All the above were full-grown males, and the blood was 

 obtained from small incisions of the lips. The corpuscles in 

 the different varieties appeared to be of the same size; the 

 most frequent diameters being l-6000th, l-5615th, l-5331st, 

 and l-5028th. Extreme sizes 1-71 10th and l-4570th of an 

 inch. 



XXIII. Proceedings of Learned Societies. 



IIOYAL SOCIETY. 



Feb. ST.'T^HE reading of a paper entitled, " On the Chemical Ac- 

 1840. tion of the Rays of the Solar Spectrum on Preparations 

 of Silver and other Substances, both metallic and non-metallic ; 

 and on some Photographic processes ;" by Sir John F. W. Her- 

 schel, Bart., V.P.R.S., &c., was resumed but not concluded. 



March 5. The reading of a paper entitled, " On the Chemical 

 Action of tbe Rays of the Solar Spectrum on Preparations of Silver 

 and other Substances, both metallic and non-metallic ; and on some 

 Photographic processes ;" by Sir John F. W. Herschel, Bart., 

 V.P.R.S., &c., was resumed and concluded. An abstract of this 

 paper has already appeared in vol. xvi. p. 331 of this Magazine. 



A paper was also read entitled, " Remarks on the Theory of the 

 Dispersion of Light, as connected with Polarization ; " by the Rev. 

 Baden Powell, M.A., F.R.S., and Savilian Professor of Geometry, 

 Oxford. 



Since the publication of a former paper on the subject referred to, 

 the author has been led to review the subject in connexion with the 

 valuable illustrations given by Mr. Lubbock of the views of Fresnel ; 

 and points out, in the present supplement, in what manner the con- 

 clusions in that paper will be affected by these considerations. 



A paper was also read, entitled, " Further Particulars of the Fall 

 of theCold Bokkeveld Meteorite ;" by Thomas Maclear, Esq., F.R.S., 

 in a letter to Sir John F. W. Herschel, Bart., K.H., V.P.R.S., &c. 

 Communicated by Sir John Herschel. 



This communication, which is supplementary to the one already 



