E. H. Griffith, Pat. Dec. 14, 86, Rochester N.Y., #957, c. 1889
The microscope is shown with the nickel plated fittings that are used to attach an oil lamp to the microscope. While the oil lamp and its holder pictured are not original equipment, they are included here to illustrate how a lamp can be mounted.
Among the accessories supplied with this microscope are two Griffirth objectives, a 2/3 and a 1/5 with canisters, one eyepiece labeled B, a sub-stage fitting having a Society Screw, and an Abbe condenser. Also, included are the nickel plated fittings that are used to mount an oil lamp. Everything is stored in a wood case having back leather covering and plush mauve lining.
The following was extracted from The Journal of the Royal Microscopical Society, 1883:
Club Microscope: (Proc. Amer. Soc. Micr., 5th Annual
Sleeting, 1882, pp. 149-52, Ser. 2, Vol. III).
The original "Griffith Club Microscope"
was described in Vol. I. (1881) p. 293. Since
that time important changes have been made by Mr. E. H.
Griffith, so that very little of the original form is
left, as will be seen on comparing figs. 8 and 9 with
the earlier illustrations. It retains its
original name in appreciation of
the honour conferred on the inventor by the " Griffith"
Clubs of Detroit and Danville, U.S.A. It is a
full-sized instrument and the main and draw tubes have
the Society screw. The coarse adjustment is effected by
rack and pinion on the "Jackson" principle, and has
about 3 in. of motion. The fine adjustment, which
appears to be both simple and efficient, is
effected by the application of a
worm-wheel and tangent-screw to the axis of the pinion
of the coarse adjustment. The worm-wheel is on this
axis, near the limb, and it is acted upon by the
tangent-screw being sprung against it, the milled head
of which is shown behind the limb in fig. 8. When the
coarse adjustment is in use, a " snail "-shaped lever
on the right of the limb (handle shown beneath the
large milled head) forces the tangent-screw from
contact with the worm-wheel, a spring latchet locking
it in position (for the example represented in this
collection, a different mechanism is used to engage the
fine adjustment (see below)). By releasing the "
snail" lever the tangent-screw is pressed into the
worm-wheel, and acts upon the coarse adjustment so
slowly that objectives of high power can be focused
with it. It will of course be understood that when the
tangent-screw is sprung against the worm-wheel the
coarse adjustment is no longer operative, which Mr.
Griffith considers to be a protection against breakage
of slides. A similar system of fine focusing was
adopted in England many years ago, and is still used in
some of Plossl's models. The stage clips are supported
on a bar above the stage, allowing the slide to make
almost a complete revolution. The mirror-bar is
adjustable in length, and the mirror can be set at any
angle above or below the stage, allowing any obliquity
of illumination for opaque and for transparent objects.
The standard divides midway between the body and the
foot, and the base may be detached, and the body set on
an extra standard (fig. 9), with a screw at the end for
fixing it in a tree, laboratory table, &c. The base
being inverted and placed on a spindle, which is always
in position in the box, becomes a turntable, provided
with self-adjusting clips for holding the slide. Three
rods, with silvered balls at one end, are the supports
for the Microscope, and they give momentum to the
turntable when in use. Two small holes in the edge of
the turntable foot allow the attachment of an
adjustable lamp-holder, which is furnished with a lamp
for class, lecture, and exhibition use. A case about 7
in. long, 5 in. wide, and 3 in. deep, internal measure,
holds the instrument when packed (fig. 10), and it may
be taken down and packed for travelling or be taken
from the box and set up ready for use in a few seconds,
" making the Microscope not only a first-class
monocular for home and office use, but also for the
tourist and the naturalist." The Bausch and Lomb
Optical Company are the makers.
The method of engaging fine adjustment mechanism used on the later example shown on this page is different than the more simple mechanism described in the above extract from the JRMS. This newer mechanism allows the fine and coarse to be engaged simultaneously. The new mechanism was illustrated and described by Griffith in an article published in the American Monthly Microscopical Journal, 1889 as follows:
Griffith’s Fine Adjustment.
By E. H. GRIFFITH, FAIRPORT, N. Y.
In Fig 1 Nos. (1) (2) (3) represent the milled head, pinion-axis, and pinion of the ordinary method of coarse adjustment. The milled head (1) is countersunk on its inner side, and the small wheel (4) is made to exactly fit the countersunk space, the inner surface of (1) and of the wheel (4) being perfectly smooth and flat. Attached to (4) is the socket and pinion (7), all of which are perfectly fitted over the pinion-axis (2) between the pinion (7) and milled head (1). A leather washer (5) is made to rest closely against the inner surfaces of ( 1 ) and (4). It is held in position bv another washer of metal (6) which, by means of two screws passing through it and (5) is made fast to the milled head. A small tension wheel (10) has a screw passing through both washers, also binding them to (1), and when desired, locking the coarse-adjustment by making the whole combination practically one wheel. When the coarse-adjustment is used, the spindle (8) holds (7). (6), (5), (4), so that they cannot revolve with the pinion. When the micrometer adjustment is required the friction of the leather washer makes the whole combination practically one wheel, which is turned by means of the milled head (8), giving the entire range of the coarse adjustment for the fine adjustment. Both adjustments are always ready for use when the tension wheel is properly set, except when the coarse adjustment is purposely locked to prevent accidents. All wear is taken up by the spring. Fig. 2 shows the entire combination in position. In this combination of the two adjustments into one, but one groove is required, greatly lessening the danger of lateral motion as in other microscopes where two or more grooves are needed. The one groove being close to the tube is another safeguard.
The long range of the fine adjustment is of great value, and the same is claimed for the locking device. The mechanism is so simple that it cannot well get out of order, and should any accident happen, any jeweller could easily repair it.
There are some additional refinements included with the later version of the Club Microscope shown on this page that are not present in the earlier examples described in the above Griffith article or the JRMS extract. In particular, the circular pinion socket (7) shown in Fig. 1 of the Griffith article has been given a larger diameter which results in slowing down the fine adjustment making it more sensitive. Compare the circular pinion sockets on Club microscopes with serial numbers 957 and 840.
With this later vintage Club Microscope, the sub-stage is attached to the stage in a different manner so that it can be removed more easily. Now, incorporated into the design of the sub-stage is a focusing arrangement consisting of a spiral screw tract cut directly into the mount. Turning the milled edge of the mount focuses the condenser.
The microscope shown on this page differs from the final version of the Griffith microscope that is described in Proceedings of the American Microscopical Society, Vol. 14, No. 1, pp. 53-56, 1892. The sub-stage is still attached to the stage and not attached to the tail piece of the limb as in the final version. The centering adjustment of the sub-stage, present in the final version, is absent on the microscope shown here. A diagonal rack was used in the final version, while the microscope on this page retains a straight rack.
The Dec. 14, 1886 patent granted to
Ezra H. Griffith concerns the removable base of this
microscope which can serve as a self-centering
turn-table for ringing the cover-glass
in the preparation of a microscope