43 
The Author’s attention was drawn to a paper on this subject, 
which appeared in the Scientific American, and was copied 
into the Mechanics’ Magazine of October 20th, 1865. 
Mr. H. L. Smith of Kenyon College, had contrived a plan 
for the illumination of opaque objects, by placing a small 
mirror in a'rectangular box, which could be attached to any 
ordinary microscope, this mirror was made adjustable imme- 
diately over the opening of the back of the objective, a light 
was placed at the side of the box and reflected down through 
the objective on to the object. In this manner the object 
could be illuminated when the high powers were used. 
Mr. Hurst suggested that a discussion on this subject would 
be of interest to the members of the Microscopical Section. 
The Author not having time to make one of Mr. Smith’s 
apparatus, thought it possible to arrive at similar results by 
the employment of the binocular microscope, an instrument 
which is now more common than a monocular instrument. 
The trial quite answered his expectations. The simplest 
method and one which gave good results, is to remove the eye 
piece from the oblique body and fix a reflector on the top of the 
body in such a manner as to throw the rays of light down to 
the Wenham’s prism, and thence through the object glass on 
to the object. 
If a plane mirror is employed, a lens of suitable focal length 
should be placed in the body in order to get the field of view 
entirely illuminated. 
A concave mirror or lenticular prism can also be used for 
the same purpose, providing the focal length is adapted to 
the length of the body and object glasses. 
Various modifications can be adapted so as to vary the 
character of the illumination to suit the particular object 
to be viewed. In some cases the Wenham’s prism may be 
withdrawn a little, to produce the proper effect. 
