the lenses at one end. Each object glass is so threaded that it can be placed in the microscope 
body in two ways, one way having the tubular mount projecting out of the body and the other 
with the tubular mount inside the body. By this means the distance between object glass and 
eyepiece is made to ciffer very considerably and wicely different powers are therefore obtained. 
The optical performance is not interfered with as the object glass by this process is reversed 
By the use of two pairs of eyepieces, also of different powers, 
four powers are therefore obtained with the same object glasses. 
The accompanying diagram illustrates the principle upon 
which the Binomax is made. The object glass (a) is shown screwed 
_ on to the body with its lenses projecting in front of the microscope. 
In dotted lines the position (a’) is shown into which it can be 
screwed in the interior of the body. The image is formed by this 
object glass at a position (b) and is examined by the eyepiece. 
The point (0) is the position of the object. The distance between 
the object (o) and the position (a) and the distance between (0) 
and the position (a’) are so arranged that (oa) is equal to (a’b) 
and (oa’) is equal to (ab). The image is therefore in focus at (b) 
whichever way the object glass is screwed on to the body, but 
different powers are obtained. If the object glass is corrected to 
work in the position (a), it will also work in the position (a’) and 
provided that the lenses are reversed, which is done by reversing 
the whole mount, the optical corrections are in each case equally 
perfect. In a binocular instrument the object must lie at the 
intersection of the two optic axes of the microscopes and the change in power is therefore made 
without altering the distance between the object and the bodies of the microscope. 
In order to obtain an extra large field of view with the higher power eyepieces, we supply 
also the wide field form of eyepiece. The size of field of view will be seen in the following 
table :— 
Diameter of field of view 
with wide field eyepieces 
_ Diameter of field of view 
with Huyghenian eyepieces 
Magnifying powers. | Working distance. 
x4 110 m.m. 33 m.m. | oF 
x8 110 mm. 22 m.m. 35 m™m.m. 
x 16 75 m.m. 9 m.m. == 
on fom mas 5 m.m. 9 m.m. 
a 
The Binomax is so arranged that the body can be used interchangeably on any form of the 
stands listed, thus if desired one Binomax body can be purchased and several of the stands 
employed 
Or 
Or 
