PROCEEDINGS OF THE SOCIETY. 
417 
delicate tlie workman sliip that could be expended upon this portion of 
the instrument, the greater would be the advantage gained. He was 
satisfied that the adoption of these agate bearings would give a continuity 
and precision of movement which under such circumstances would be of 
immense advantage. 
Mr. Goodwin exhibited a form of eye-piece for the Microscope, which, 
though not entirely new, he thought might be of interest to some of the 
Fellows of the Society, It had been designed by himself, acting upon 
the exigencies of the moment, by arranging the lenses so as to give a 
large field with considerable magnifying power. It would be seen from 
the drawing (made on the" board) that it was the Huyghenian eye-pieee 
modified by the introduction of a second plano-convex eye-lens, the 
convex surfaces of the two eye-lenses facing : the result was a field 
which was both large and flat, similar to that of a Kellner eye-piece but 
somewhat flatter. Some persons may find it troublesome to use on 
account of the angle of vision being too large to suit their eyes ; this 
was a matter of personal equation, and was capable of being met by a 
slight modification in the construction. Since he had first exhibited this 
eye-piece he had found that Steinheil made one identical with it about 
twenty years ago ; this fact was, however, unknown to him at the time 
his was designed. He had found it necessary to modify it somewhat 
since it was originally made, for although it worked well with his own 
objectives, it gave too much colour with those of other makers. To 
meet this difficulty the two eye-lenses had been fitted to slide in the 
tube, so that the distance between them and the field-lens could be 
altered as required, and this not only answered the purpose, but was of 
advantage in providing a means of adjustment which greatly assisted in 
the collar-correction. An alteration in the distance of 1/20 in. made a 
remarkable difference in the collar-correction. 
Mr. A. W. Bennett said that a paper of great interest had been placed 
in his hands to bring before the meeting, “ On the Freshwater Algae of 
North Wales.” It was, however, hardly a paper to be read on that occa- 
sion, because of its technical character and the long lists of species of 
which it largely consisted. He merely indicated the nature of its 
contents, as the paper itself would be printed in the Journal. 
The President said that the thanks of the Society would no doubt be 
cordially given to Mr. West for his valuable paper, and to Mr. Bennett 
for the account which he had given them of its contents. 
The President drew the attention of the meeting to Mr. Eousselet’s 
tank, which was exhibited in the room (as described and figured in this 
Journal, p. 90 ). The trouble of catching a quick and lively rotifer in a 
tank, especially if nothing bettor were used than a watchmaker’s eye- 
glass, was to him a matter of painful experience. In order to have both 
hands free, he had made for the purpose a pair of spectacles having one 
eye blank, and the other fitted with a high-power lens. For his 
purpose he should prefer to have a smaller tank, in order that he could 
use a higher power which would focus through, and then, if put against a 
1890. 2 G 
