MECHANICAL PORTION OF THE MICROSCOPE. 
beneath the stage is carefully centered and fitted to receive the 
achromatic condenser and polarizing apparatus. 
The plane and concave mirrors (the latter inches in 
diameter) can be turned freely in any direction, or so adjusted 
as to give very oblique light. The instrument has a gradu- 
ated draw-tube, and the whole microscope, with all the acces- 
sory apparatus, is packed in a fiat mahogany case of very 
convenient dimensions. 
54. Tlie Microscope shown in Fig. 14, is of the largest class, 
complete in all its parts, and constructed upon the most perfect 
model, suggested by the combined experience of the most 
eminent American microscopists. 
This microscope is mounted upon a strong brass tripod, with 
uprights of bell-metal supporting the axis, upon which the in- 
strument can be inclined at any angle. The stage is four 
inches square, movable freely in every direction by a lever ; it 
also revolves around a steady centre, coinciding with the opti- 
cal axis of the microscope. 
The under side of the stage is fitted for the attachment 
of accessory apparatus. The mirrors, plane and concave, (the 
latter three inches in diameter,) are mounted with a cradle 
joint, and movable arm attached to a sliding support, giving 
facility of movement in every direction. 
The compound body has a graduated draw-tube, and is 
attached to a heavy socket which is moved up and down on a 
strong triangular bar of bell-metal, by rack and pinion, by 
which means the coarse adjustment is efiected with great 
steadiness and freedom from tremor. 
The fine adjustment of focus is efiected by a screw acting 
upon a lever, which moves a short tube carrying the object- 
glass. This tube is held down by a spring, which, like a 
similar spring in FTo. 6, diminishes the danger of injuring the 
object-glass. 
This instrument is finished in the most perfect manner 
throughout, and is designed for scientific institutions, and for all 
who desire to possess the most perfect and completely furnished 
instruments. 
J. k W. GRUNOW & CO’S ILLUSTRATED 
