757 



was placed over the eye-piece, two distinct images appeared, one of 

 which revolved round the other when the eye-piece was turned round, 

 thus showing the ordinary and extraordinary rays. On the second, 

 the Nicol's prism was applied under the stage, the other arrange- 

 ments remaining the same. Upon turning the eye-piece, although 

 two images are produced, but one is seen when half the revolution is 

 peformed, i. e. at 180° from the first position. Changes also take 

 place at every other quadrant. In the third experiment, the selenite 

 plate was interposed, the images were now coloured, and presented the 

 complementary colours at every quarter of a circle. When the hole 

 in the piece of brass was of a large size, the images were seen to- 

 overlap, and white light was produced. The author concluded with 

 some remarks upon the service likely to be rendered to microscopical 

 investigation by the employment of polarized light." — J. W. 



BOTANICAL SOCIETY OF EDINBURGH. 



Thursday, January lith, 1847. — Sir William Jardine, Bart., in the 

 chair. 



Donations to the library and museum \\ere announced — from Mr. 

 W. Gardiner, Dundee, the second edition of his book on Mosses, and 

 catalogues of Musci and Hepaticae ; from Dr. Bell Salter, Hyde, Isle 

 of Wight, a set of Fruticose Rubi ; from Mr. R. M. Stark, Mosses, 

 Hepaticae, and Algae ; rare English plants, collected by Mr. Wm. 

 M'lvor, from Professor Balfour ; and rare Irish from Mr. David Moore, 

 Dublin. There was also presented a complete set of maps and tabu- 

 lar forms, relative to the arrangement of natural-history collections, 

 mounted on pasteboard, by Mr. W. Brand. 



The following communications were read : — 



1 . On Fairy Rings, by Dr. George Wilson. The object of Dr. Wil- 

 son's remarks was to show that the chemical theory of the origin of 

 these remarkable circles, laid before the meeting of the British As- 

 sociation, held at Southampton in September 1846, by Professor Way, 

 of Cirencester College, was identical with that published by Wollaston 

 in the Philosophical Transactions for 1807. Dr. Wilson also pointed 

 out that analyses of various Fungi had been made by Prof. Schloss- 

 berger, of Tubingen, and Dr. Doepping, long before Mr. Way pub- 

 lished his, and thought that these gentlemen's names deserved to be 

 mentioned, as confirmers of Wollaston's views and predecessors of 

 Professor Way, in establishing the probability of the chemical theory 

 Vol. II. - 5 c 



