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SUMMARY OF CURRENT RESEARCHES RELATING TO 
A Farmer’s Microscope. — Mr. E. M. Nelson writes: — “Two or 
three months ago a scientific farmer asked me if Watson’s histological 
Microscope was suitable for a certain kind of investigation, which he 
described. To this I replied that in its present condition it was not 
suitable, but with a few alterations it could be made serviceable for the 
purposes he had named. He desired me to have these alterations carried 
out, and, as he gave me a free hand with regard to all the details, the 
result is the Microscope before you. 
Two features are noticeable at once: — (1) There is no fine-adjust- 
ment ; (2) The main stage is very large for the size of the instrument, 
viz. 4 by 4 in. The body and the foot are of the usual form, but the 
principal alterations will be found in the stage. 
Fig. 3. 
Fig. 4. 
The hole in the stage is 1 in. in diameter, and it can be closed by 
a sliding plate underneath. When it is closed it forms a dark well 
for the observation of seeds and similar objects under a low power. 
The stage has two carriers, one of the ordinary sliding type which need 
not be described. The other, which is much larger, viz. 61 by 2J, has 
no aperture in it, but has a ring compressor 2 in. in diameter, which is 
worked by a lever and spring, precisely like a letter-clip (see figs. 3 
and 4, drawn one-third scale). This is for the purpose of holding 
leaves and similar objects. 
The mirror is a silvered equiconvex lens, an invention dating from 
the last century. 
The instrument has, however, another mirror on the same principle 
for superstage opaque illumination. At the right-hand side underneath 
the stage is a rotating bar to hold this mirror, which is mounted on a 
rod. The focus of the mirror is made equal to the distance of the dark 
well, and in practice its performance will be found most satisfactory. 
It is 1J in. in diam., and concentrates a powerful beam on the object. 
We have here a cheap and thoroughly practical piece of apparatus, which 
might with benefit be applied to other instruments. This will be found 
preferable to the old plan of a bull’s-eye placed in front of the stage, 
where it is always in the way. The mirror being at the back of the 
stage interferes with stage manipulations no more than the limb of the 
Microscope. 
The lenses selected for use with this instrument also demand notice. 
