ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
543 
the ready turning of the object without interference of the pin or danger 
of injury to the specimen. As this large opening will admit light 
beside the condenser in bacterial work, it must be fitted with an adapter 
with a smaller opening. In this work, also, the rectangular movement 
of a mechanical stage is a great convenience for bringing insects readily 
into the field. 
As I accomplish all these purposes perfectly by a single Microscope, 
it seems to me that this instrument must be adapted substantially to 
everything which the biologist is likely to want to do with a Microscope, 
and that a description of it may interest many situated similarly to 
myself. 
My starting point is a Zeiss stand, No. 1, with oculars 1 to 5 (No. 3 
being divided for the insertion of a micrometer), and objectives ranging 
from A 3 to an apochromatic 1-12, with the corresponding eye-pieces. 
For ordinary binocular work I have a Zeiss binocular eye-piece, which 
has the advantage over any other binocular arrangement that it does not 
so increase the height of the instrument as to make it inconvenient to use 
it with low powers while sitting. 
The special feature of the instrument is the stage, which is the 
simplest form of mechanical movement in two rectangular directions, 
Fig. 58. 
adapted to the square stage of my instrument as illustrated by the 
engraving accompanying (fig. 58). The stage-plate of the Microscope is 
altered only by a triangular groove along the whole length of the 
lateral margin, and by an enlargement of the central aperture. Into 
this a heavy diaphragm may be slipped with an opening of the usual 
size for the Abbe condenser. 
