with rackwork to the body tube. Below the stage is a post carrying a
plano-concave mirror on rotating support. A housing with rackwork
holds the condenser; also a bar capable of holding a central stop, and
achromatic condenser. The mechanical stage is to the design o f
Edmund Turrell, with X/Y motions on concentric shafts. The stage is a
push-fit over a projecting rim on the stage plate, has a micrometer scale
0-20 on the flat, and 0-100 on the wheel. Engraved on stage: One turn
o f Micrometer = 1/100 o f an inch. At the top of the stage is a sliding
spring-loaded grip for slides. Upper stage plate may be removed and
replaced by a larger one, also with a spring grip.
Accessories
Objectives:
in brass can engraved Minch, with lieberkuhn;
in brass can engraved 1 inch, with lieberkuhn;
in brass can engraved 1/2, with lieberkuhn, objective has a
correction collar;
in brass can engraved 1/4, with lieberkuhn, objective has a
correction collar;
in brass can engraved 1/8, with correction collar;
in brass can engraved 1/16, with correction collarT'T
Two eyepieces, not numbered; each has an outer cap that fits over eye
lens and has one bayonet catch. Cap is removed when camera lucida
used. Another eyepiece is fitted with a cross wire, and a sliding adjustment
to correct for user’s eye. (The field lens is hygroscopic.) A further
eyepiece is fitted with a micrometer.
Camera lucida of the Soemmerring type (small circular mirror on a
stalk, mounted on a split ring to clip over eyepiece). Aperture disc with
four apertures, 3 to 16 mm.S^ish-plate S 7 7 x 56);i.:stage forceps; two
live-boxes; tweezers; key to tighten trunnions. Other items: brass strad-
Ijfe clip; brass rod (length Wjf ' which can push into hole in the limb,
now fitted with a 90° arc (not Powell manufacture); also brass rod
(length 190), screw thread at one end; black screen on a pin with a disk
of five apertures, screen measures 97 x 125. Small envelope, labelled in
ink, ‘The Micrographic Card’.
Mahogany box for microscope and accessories, fitted with red leather
on Supports. Drawer at base, released by pin in rim of box beside lock.
Box has a Bramah lock inscribed: [crown symbol] PATENT S. Mordan &
Co. MAKERS. LOND ON.
Purchased in 1844 for Dfl. 852.25.SPowell (1842),
“Description of Messrs. Powell and Lealand’s Newly-Constructed
Achromatic Microscope^ Turner (1980), chapter 6, fig. 2; Turner
* 9 8 9 - S | f c |3 .
588 MICROSCOPE: COMPOUND (373) 1866
Signed: G. &t S. Merz in Miinchen
Foot width 119, depth 116; height to top of pillar ljSi^H
overall height^ 310
Box 370 x 210 x 180
588
The brass horseshoe foot is finished in a deep khaki lacquer, and has a
brass rectangular pillar supporting the stage (diameter 95). At the back
of the stage rises a triangular side pillar with fme-focus' adjustment
iptiw, and an armlfo carry the optical tube. The stageMgS rotate,
including the side pillar and optical tube. Below the stage is a planoconcave
mirror on a swing'ariil!, and its vertical position can be adjusted
by a slide in the pillarjand locked by a knurled knob. Below the stage