HALL'S CONDENSER BY SWIFT

c. 1868-1880

 

The elements of this condenser include:
A. The Optical portion includes two or three planoconvex lenses. The top element is easily removed for lower power work.
B. Rack and pinion adjustment of focusing.
C. A slide close to the optical elements containing different size stops for dark ground illumination.
D. The large disk that carries elements E thru L.

The elements carried on D include:
E. A rotating tube which carries three orthogonal slits suitable for oblique illumination from more than one direction used especially when observing test diatoms.
F. A disk of 7 graded apertures.
G. A polarizing prism
H. A wheel containing two selenites and one empty slot.
I. An adjustable oblique light shutter.