118 PROCEEDINGS OF SOCIETIES. 
Mr. Lapp suggested that much of the milkiness might be owing 
to the refraction of the light, because nearly one half of the light 
was reflected on the object, and the other half was reflected 
through and would strike the side of the object. It was difficult 
to destroy the whole of the light from the surface, and a great 
deal of the milkiness was, he thought, due to this cause. 
Mr. Hatt said that, in using Messrs. Powell and Lealand’s 
reflector, he had got rid of part of the milkiness by covering up 
the back portion with a piece of black paper as a temporary expe- 
dient, with a hole in the middle of it as a diaphragm. 
A Member thought a better plan would be to use a piece of 
black velvet, with a hole through the opposite side; and if the 
milkiness proceeded from the cause supposed, the light would 
then die away. 
Mr. Logs expressed the pleasure he felt at being made the 
medium by which Professor Smith introduced his plan to the 
notice of English microscopists, and felt confident that, in the 
end, good results would be obtained from it, though it was yet in 
its infancy. He did not wish to object to any method, nor was 
he prejudiced in favour of the American plan, but certainly it 
had the advantage of possessing a motion for turning the silver 
reflector at any angle, and putting it at any distance that might 
be necessary, when using different powers. Mr. Lobb then referred 
to the objection that the reflector covered too much of the field, 
and explained Professor Smith’s diagrams with a view to show 
that it really covered very little of it. As regarded parallel glass, 
he thought with Mr. Brooke that this was a very important point, 
and that Mr. Lealand’s idea of placing a piece of perfectly parallel 
glass at the proper angle might be carried out with the best pos- 
sible results. Mr. Lobb proceeded to explain an object-glass for 
the polariscope he had some time since invented in order to look 
at erystals above the eye-piece, and explained, by a reference to 
the various parts of the illuminator, the way in which it had been 
applied to that instrument.* The field was beautifully illuminated, 
and the object came out without cloud or milkiness, and by using 
a 1 object-glass the whole field might be easily illuminated with-- 
out any fog. There was a fog which partly arose, as Mr. Slack 
had explained, from using high powers, but then with high powers 
a small portion only was in focus. That portion, however, was 
perfect, and no more than this was wanted. Mr. Smith, of Bow, 
had called upon him (Mr. Lobb), and communicated to him a 
very ingenious idea. Mr. Smith used a binocular instrument, the 
prism being the illuminator; there was a reflector placed at a 
certain angle above the left-hand tube of the binocular body, and 
the eye-piece being removed, and the light sent down from this 
reflector and by the prism, the object was illuminated ; and this, 
it was stated, answered admirably. The objects must all be unco- 
vered, and some study was necessary to determine the best ground 
to put the object on. At present the best ground was perfectly 
* To give this in detail diagrams would be necessary. 
