PROCEEDINGS OF SOCIETIES. 211 
very remarkable manner ; thus the effect of the conversion upon 
the eggs of a small Lepidopterous insect was to make them appear 
as if laid open and seen from their interior face ; the same was the 
ease with the spherical and bell-shaped polycystina, and with such 
diatoms as Isthmia; whilst the convex and concave faces of Arach- 
nodiscus were mutually interchanged. Dr. Carpenter also exhi- 
bited a (true) half-inch objective, constructed for him by Messrs. 
Powell and Lealand, specially adapted, by the limitation of its 
angle of aperture to 40°, for use with the binocular. The focal 
depth or penetration of this objective, combined with entire free- 
dom from that exaggeration of relief which is necessarily produced 
when objectives of an angle of aperture much exceeding 40° are 
used with the binocular, were displayed in such a manner as to 
satisfy the most critical judges, upon a beautiful slide of poly- 
eystina prepared for Dr. Carpenter by Mr. Freestone. 
Messrs. Crovucnu.—Fourteen microscopes, including several of 
their “cheap binocular microscopes.” This instrument is of a 
very superior construction, and optically as perfect as the most 
complete and expensive, and fully bears out the testimony of Dr. 
Carpenter and other eminent microscopists as to the great supe- 
riority of this binocular as a “ cheap ” instrument. 
Messrs. Govutp AND Porrur.—Lleven microscopes, including 
their portable sea-side microscope, admired for its cheapness and 
compactness ; it has coarse and fine adjustment mechanical rack- 
stage, three sets of achromatic powers, best condenser on stand, 
with sliding, centre motion for inclining it to any angle, and fits 
into a case 52in. by 5} in., and 3in. deep. 
Mr. J. How.—Ten microscopes. Among the objects exhi- 
hibited by reflected light, were curculio of hazel, small intestine, 
human, lung of boa constrictor, foraminifera, polyeystina; by 
transmitted light, female gnat, head of crane fly, gizzard of 
cricket, foraminifera, Mediterranean diatoms (assorted); by 
polarized light, platino-cyanide of magnesium, salicine, and 
chlorate of potash. 
Mr. Lapp.—Seven microscopes of different construction. One 
fine mounted specimen of the itch insect, one live specimen of the 
Conochilus Volvox, two polarized objects, especially one of the 
coral from the mountain lime-stone, forming a most brilliant 
object. | 
Messrs. Murray AND Heatu.—LZight microscopes. Among 
others their new model, combining perfect steadiness with large 
range of adjustment, ata small cost. The objects were Vorticella, 
Ophiura, 4tea dilatata, 8. Australia, peristoma of Bryum, spiral 
vessels of rhubarb, polycystina, diatomacex, guano, &c. 
Messrs. Newron AND Co.—Twelve microscopes. The objects 
were diatoms, polarizing objects, and injections; also a series 
of large preparations 8 inches in diameter, for gas. Microscopes, 
including scorpions, tarantulas, crabs, locusts, butterflies, &c. 
Mr. Norman.—WNine microscopes. Some of the objects dis- 
played were of great beauty, and a few worthy of particular 
