56 PROCEEDINGS OF SOCIETIES. 
radically opposed to many of the received ideas, and in favour of 
lenses of the widest angle of aperture for all kinds of work; even 
going so far as to express his opinion that most of the work in histo- 
logy and pathology done with the so-called “working lenses” of 
narrow angle, would require further attention, and with wide-angled 
objectives which recent advances of the optician have put at our 
command. 
After the reading of the paper, the meeting was resolved into a 
conversazione for the examination of the various instruments, objec- 
tives, and specimens which had been brought by the members of the 
Society and their guests. 
Mr. Mills, of Buffalo, exhibited a beautiful specimen of Crouch’s 
large binocular stand, and various lenses, among them an immersion 
No. 10 (,;th) by Hartnack. The exhibition of the circulation in 
Chara, by Mr. Mills, under the binocular with a power of 75 dia- 
meters, attracted much attention. Dr. Kenyon exhibited a Powell 
and Lealand ;!,th of recent construction, with dry and immersion 
fronts. Mr. Fell exhibited a late immersion 4th by Gundlach. 
Professor Smith exhibited a Zentmayer army hospital stand with 
extra thin stage of his own design, Tolles’ ~5th and }th duplex 
objectives of 180° (+) air angle, Tolles’ 4 and { inch solid eye- — 
pieces, amplifier, &c.; also a microscope lamp of new construction. 
The flame of this lamp is only about 24 inches above the table. 
Kerosene oil is burned: there is no chimney, the draught being 
supplied by a small fan driven by clockwork: the lamp burns with 
a perfectly steady flame of great intensity. 
The President exhibited a Queen’s student’s stand with three eye- 
pieces, Tolles’ l-inch objective of 30° aperture, and Tolles’ jth 
duplex immersion objective of 95° balsam angle. 
The following severe tests were exhibited by Professor Smith to 
convince the doubting ones (of whom several were present) of the 
correctness of the positions assumed in his paper. 
1. Navicula (Pleurosigma) angulatum, resolved into hexagons, 
direct light, central illumination being secured by a diaphragm plate 
perforated with an aperture 5}, of an inch in diameter, and accu- 
rately centered. 
2. The transverse strie of Amphipleura pellucida (Navicula acus) 
—the No. 20 of Moller’s balsamed plate, illuminated by Wenham’s 
“reflex” (in this case direct) illuminator: amplification 2000 dia- 
meters. 
3. Nos. 18 and 19 of same probe-plate, with same amplification 
and illumination. 
4, Resolution of the 19th band of Nobert’s 19 band test-plate 
(lines 112,600 to the English inch) with ordinary oblique illumina- 
tion 75° from axis. 
(All of the above with Tolles’ duplex (four-system) wet 5th 
of 1875.) 
5. Resolution of the 19th band of Nobert’s 19 band test-plate 
with Tolles’ 1th immersion (duplex) objective of 1876, B eye- 
piece : amplification 540 diameters, illumination as in No. 4. 
