Geo. Wale, Pat. App. for
The New Working Microscope, c. 1880
Iris Diaphragms.—To the " Working Microscope " of G. Wale an inexpensive and very simple and ingenious form of " iris" is adapted, shown (separated) in Fig. 121. It consists of a piece of very thin cylindrical tube A, about 3/4 inch in length and £ in. diameter, the whole circumference of which is cut through with shears to nearly its whole length at intervals of about 1/4 inch ; by means of a screw-collar B, attached below, this cut tube is forced into a parabolic metal shell (contained within C) whose apex is truncated to an aperture of about 3/8 inch ; the pressure of the screw causes the thin metal tongues to turn and to overlap in a spiral which gradually diminishes the aperture to the size of a pin-hole. On unscrewing the collar B, the spiral overlapping of the tongues is released somewhat, and their elasticity causes the aperture gradually to expand. As adapted to the stage of the " Working Microscope," the iris, when unscrewed until its aperture is smallest, is then almost in contact with the base of the slide ; when at its largest expansion it is about 1/16 inch lower. The whole device is fitted into the opening of the stage from beneath (so as to be flush with the upper surface) with one turn of a very coarse screw on the edge of C—a far more convenient plan than the " bayonet joint."
From an advertisement in The American Journal of Microscopy, 1880 :
THE NEW WORKING MICROSCOPE.
This Microscope has just been brought out by Mr. Geo. Wale, whose
reputation as a maker of flne stands is so well known. It embodies
several new and important features, foremost amongt which is the method
of hanging the body, so that it may be made to incline at any angle.
The method now in general use for this purpose changes the position of
the centre of gravity of the instrument, and renders the microscope
more or less unsteady. The new method avoids this difficulty. The stage
is of a new construction, very thin, so as to admit the greatest
obliquity in the illumination of objects, and with clips which move
round it, thus giving many of the advantages of a rotary stage. The
clips may be easily and quickly removed, so as to leave a clear stage,
and they may also be so applied as to Hold the slide against the under
side of the stage, when very oblique light is required for resolving
difficult test objects. The diaphragm is of the Iris pattern, a form
wnich is generally acknowledged to be the best, but which has hitherto
been very costly, those usually supplied being sold for $16. This Iris
diaphragm is a new form, which, with several other features of this
stand, has been patented by Mr. Wale. It may be easily and quickly
applied or removed.
INDUSTRIAL PUBLICATION COMPANY, 14 Dey Street, New York
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