NEW MICRO-TELESCOPE. 609 
The rack-movement now only varies the power, and may be thus 
used as a fine adjustment, while the coarse adjustment must be 
ained by moving the whole instrument. This combination is 
extremely useful for dissecting, its great- Fig. 110. 
est misfortune being that it is a mo- 
nocular arrangement. (D) A Telescopic 
Object Glass of one inch linear aperture 
and four inch solar focus, to be screwed, —— 
instead of the objective, into the bottom 
of the Draw Tube. To this Object Glass 
the compound body with its eye-piece 
and objective acts as an erecting eye- 
piece, and is focussed by means of its 
rack-movement. This combination gives 
a telescope of good working qualities, 
and of power entirely disproportioned to 
its size. (E) A brass Pillar (Fig. 110) about two inches long, 
having a steel transverse bar for a handle, and at its lower end a 
gimlet-screw to be fastened into a tree, post, or board. Into its 
upper end may be screwed the upright pillar of the Tank Micro- 
scope: The gimlet screw may be made of steel, which is some- 
what durable, or a common iron screw may be used, which easily 
wears out but can be replaced at a nominal expense. This fixture 
adapts the instrument to field use, as a microscope or telescope. 
This instrument should be furnished with a compressor and two 
objectives,—a one-inch and a two-inch, two-thirds inch, one-half 
inch, or four-tenths inch, according to the wants of the owner. 
Either of these objectives may be used as an erector, though the 
higher ones will seldom be preferred for this purpose. The four 
or five inch objective usually furnished with tank microscopes may 
well be dispensed with, as its effect is easily gained by means of 
the erecting arrangement. Microscopists who have laid aside the 
ordinary “‘erector” of the shops as an entirely unsatisfactory 
affair, need not, on that account, expect a similar per, in the 
use of a good one-inch or two-inch objective as an erecto 
The cost of this instrument ought not to be large. Tt should 
not exceed sixty or seventy dollars to those already supplied with 
objectives and compressors, or one hundred dollars, complete. 
Tue following papers were also read in the Subsection of So 
Report on Photographing Histological Preparations by Sunlight.— By Dr. J. J. 
Fee NS ca k nee bette ot nalts E a ie tac OR: 
