742 PKOCEEDINGS OF THE SOCIETY. 



obtained for low powers, and especially for dark-ground illumination. 

 The ordinary oil lamp had a candle-power of 3 to 3^, whilst this lamp 

 had a candle-power of 8, and any greater power was quite unnecessary. 

 It was mounted with a brass collar terminal for use with the ordinary 

 bayonet-joint holder. 



The greatest advantage was obtained when used for dark-ground 

 illumination, when all minute details such as fine hairs, cilia, &c, were 

 shown remarkably well. For transmitted light with low and medium 

 powers it was best used without the bull's-eye, it being then only neces- 

 sary to rack up the condenser very slightly in order to get rid of the 

 image of the incandescent filament. He" did not, of course, pretend 

 that this lamp would replace the edge of the flame for very critical 

 work with high powers ; but for ordinary work with low powers up to 

 the half-inch he could recommend it as most efficient, and very con- 

 venient for those who had the electric light laid on in their houses. 



Mr. Eousselet, in reply to a question by Mr. J. J. Vezey, said that 

 he was accustomed always to use this lamp with a shade. 



The thanks of the Society were then cordially voted to those gentle- 

 men who had brought the various instruments for exhibition. 



The President said the Society had arranged for an exhibition that 

 evening of a peculiarly interesting character, being a set of slides pre- 

 pared by the late Dr. W. B. Carpenter in connection with his investiga- 

 tions into the Shells of the Mollusca. An additional exhibition had 

 also been provided by Mr. B. B. Woodward, who had given much atten- 

 tion to this subject, and now exhibited some valuable preparations. It 

 was interesting to see Mr. Woodward pursuing the studies of his dis- 

 tinguished uncle, Dr. Samuel P. Woodward, whose Manual of the Mol- 

 lusca was a model introduction to the knowledge of this group, far in 

 advance of the days in which it was published, and not yet replaced 

 by any later handbook. He could not express the pleasure and benefit 

 he obtained as a student from Dr. Woodward's manual. 



Mr. B. B. Woodward drew attention to a series of slides he had 

 brought illustrating shell structure, some of which he thought were ex- 

 tremely fine and showed great care and skill on the part of the mounter, 

 who was one of the formatories at the Natural History Museum. 



Mr. J. J. Vezey, at the request of the President, read a short 

 abstract he had copied from the Beport of the British Association for 

 1846, page 82, being a resume of the original communication made to 

 that Association by the late Dr. W. B. Carpenter, on " Shell Structure." 

 Mr. Vezey said he knew nothing of the subject himself, but thought it 

 would enable the Fellows better to understand the slides exhibited on 

 the table if they knew the points which Dr. Carpenter intended to 

 illustrate when he prepared the specimens, though he believed the views 

 then expressed had been modified since the first paper was read on the 

 subject. 



Prof. Chas. Stewart, being asked by the President to say a few 

 words on the subject before them, said that years ago he was much 

 interested in the subject, but it was a very long time since he did any 



