USE OP WENHAM BINOCULAR WITH HIGH POWERS. 319 
there is a slight shade on either side of the field, gives per- 
fect stereoscopic effect. 
These glasses are of great excellence, and I think excel 
Zeiss’s in definition ; they have also this advantage, they are 
perfectly homogeneous, and require the ordinary cedar oil 
for either oblique or central light, and do not require any 
adjustment of the draw tube for thin covers, as is necessary 
with Zeiss’s glasses. 
Any ordinary stand made on the Jackson-Lister model can 
be used, if the body is made to come down in contact with 
the stage, as the objective only projects of an inch. 
An achromatic condensor is also necessary. I have used 
Powell and Lealand’s and Zeiss’s, but any maker’s with a 
large angle would probably do. 
