12 
see into things instead of a mere surface observation of a few Diatoms, 
for the sake of performing the feat of defining the difficult marking on 
some half-dozen of them, and this is only what such a glass is at pre- 
sent used for.” He(Mr. Hennah) considered this a wonderful admis- 
sion, and any new sytem which would give them lenses for physiolo- 
gical and natural history investigations would be a great advance in 
the utility of the microscope. 
Another altogether perfect lens for exhibition was a ¥%-inch. 
While the magnifying power was very great, the definition was 
clear and as deep as in an inch or inch-and-a-half. It was of 
85° aperture; had a good working distance, with a very large 
leiberkuhn for opaque objects, and was coned down to admit the 
pencil of light for bull’s eye or any other illumination. There was also 
the patent reflex illuminator, for getting opaque illumination, with very 
high power, which did its work admirably. Mr. Wenham, as an 
amateur, had done more than anyone else for the microscope; he had 
devised the binocular, and given it to the world, and although, by the 
advice of friends, he had allowed Messrs. Ross to patent these latest 
inventions, he had no pecuniary interest whatever in them. 
Mr. WONFOR enquired whether the higher lenses worked readily 
through ordinary covers? 
Mr. HENNAH replied that they did. He would exhibit a P. Angu- 
Zatum with a comparatively thick cover. 
Votes of thanks were given to Messrs. HENNAH and WENHAM. 
Previous to this Mr. WONFOR remarked that Dr. CARPENTER, 
F.R.S., very kindly gave him a small quantity of the Atlantic chalk, 
dredged up in the Porcupine Expedition. Some of this he had 
brought down for distribution, and, if time allowed, he would show 
that it contained foraminifera identical with those obtained from our 
chalk Downs. 
The meeting then became a conversazione, when Messrs. HENNAH, 
GLAISYER, and WONFoR exhibited various objects with the new 
lenses. Their performance was pronounced admirable. 
The one-fifteenth and one-tenth showed P. Angulatum and other 
diatoms, podura scales, and ultimate fibre from the pig equally 
well, while the half-inch gave beautiful definition and as great a depth 
as most one-inch objectives. Later in the evening, Mr. HENNAH 
strained up the half-inch with the highest eye-piece, and showed P. 
Sormosum marvellously. 
