Leitz AM petrographic compound microscope
Date: circa 1937
Inventory Number: 1999-1-0020a
Classification: Microscope
Dimensions:microscope: 38 × 13 × 25.5 cm (14 15/16 × 5 1/8 × 10 1/16 in.)
case: 51 × 25.5 × 29.2 cm (20 1/16 × 10 1/16 × 11 1/2 in.)
box: 45.7 × 25.4 × 29.8 cm (18 × 10 × 11 3/4 in.)
Accessories: standard eyepieces (3): 8X P, Periplan. OK 10X, and Periplan. Ok. 25X; wide eyepieces (3): 1, 1, 8X, 10X; objectives (4) in fitted case: 1b 4.3X, 3 10X, P7 62X, P 1/12 oel; waveplates (2); condenser with polarizer; mechanical stage; loupe 6x; box of cover glasses; standing case; key; objective adaptors (4); and watch keys (2)
Bibliography:Leitz Polarising Microscopes and Accessories
DescriptionThis is a Leitz petrographic compound microscope, model AM. The Leitz catalogue of 1937 identifies this instrument as "of exceptionally large size" with a "wide tube for eyepieces of large diameter."
The modified horseshoe-shaped base is made of cast iron coated in a glossy black lacquer. The inclination joint has a clamping lever that is nickel or chrome plated. The handle arm above the inclination joint is curved and deep to permit manipulation of large specimens. The arm is also covered in black lacquer. The lower part of the arm carries a bracket to which is attached the stage and substage illluminating apparatus. The bracket is raised and lowered by rack and pinion by means of a bright brass knob with clamping lever attached to the lower arm. The upper part of the arm has the coarse and fine focus knobs in bright brass. The coarse adjustment is by rack and pinion. The fine focus is by a micrometer screw equipped with a divided drum.
The body tube is also brass and of wide diameter. There is no drawtube. The ocular fits into the top of the body tube. Below the ocular, there is a cap analyser support with an index line. An Amici-Bertrand lens is in a centering mount with iris diaphragm, is attached to a slider, and is focusable by rack and pinion. The focusing knob is on the front of the body tube. The tube analyzer is the anastigmatic type with a correction lens mounted permanently within the tube. It is provided with a revolving mount and divided scale with intervals of 5 degrees. Below this on the tube is a slit at a 45-degree angle for the insertion of compensators. The objectives are each held in an adaptor which keeps each permanently centered. The adaptors slide one at a time into the objective clutch changer at the end of the body tube.
The stage is circular and rotatable. There is a scale on the limb and a vernier. It has a removable center ring plate and a clamping screw. The stage clips are nickel-plated (one is missing). The stage is moved by rack and pinion, as already mentioned.
The substage illuminating apparatus includes a two-iris-diaphragm type of Leitz model "aa." It has a 5-lens condenser above a polarizer prism. There is a swing-out supplementary condenser above the primary, larger condenser. Both the condenser and polarizer can be disengaged by a slide fitting with a locking lever. One iris diaphragm is above the condenser; the other is below the polarizer.
These illuminating components are mounted together on a bracket that attaches to a slider with a clamping lever. This slider travels on a track that is part of another fixture. This fixture is joined to the bracket supporting the stage but moves independently on its own rack and pinion.
The substage mirror is plano-concave and clamped by means of a screw to the stage bracket.
A standing mahognay case has a lock and key, and is fitted with sliding drawers and boxes.
Accessories include an eyepiece adaptor for use with eyepieces of standard diameter; 2 standard eyepieces (8X P and Periplan. Ok. 25X); 3 wide eyepieces (1, 1, 8X, 10X).
A fitted box lined in burgundy velvet and silk has brackets to hold 9 objectives on their adaptors. There are currently 4 objectives on adaptors (1b 4.3X; 3 10X; P7 62X; P 1/12 oel, A=1.30, 100:1). Two watch-key wrenches for centering the objectives are included. There is also a 1/4 wave glimmer plate and a Gips rot. I plate; a disk aperture stop; and a 6x loupe by Schneider-Kreuznach.
A second fitted box lined in burgundy velvet and silk holds a mechanical stage with two verniers.
A third box with a sliding lid is empty.
A red cardboard box is marked in pencil "10X." It holds a new eyepiece wrapped in paper. It is a "Periplan OK. [1]0X."
A cylindrical case of turned wood holds square cover slips. The red paper label is printed as follows:
SOLD AND RECOMMENDED BY ARTHUR H. THOMAS CO., PHILADELPHIA, PA., SINCE 1902 /
A.H.T. CO. SPECIFICATION / MICRO COVER GLASSES / NON-CORROSIVE / GUARANTEED AGAINST CORROSION / IN ANY CLIMATE /
1/2 OZ. / No. 7020 / SQUARES / 22 mm / No. 2 /
CUT AND PACKED / IN U. S. A. FROM / CHANCE MICRO SHEET / MADE IN ENGLAND / CONTINUOUSLY SINCE 1840
Signedon tube and mechanical stage: Ernst Leitz / Wetzlar
on oculars: Ernst Leitz Wetzlar
on objectives, 3 and P7: E. LEITZ / WETZLAR [in achromat trademark]
on objectives, P 1/12 oel and 1b 4.3X: Ernst Leitz Wetzlar
on top of arm: E. LEITZ / WETZLAR [in achromat trademark]
on magnification table inside case door: E. LEITZ, Optical Works, WETZLAR / Agencies: London, New-York, Tokyo, Peking
on loupe: Schneider-Kreuznach
on objectives, P 1/12 oel and 1b 4.3X, and on mechancial stage: Germany
on label of cover slips: CUT AND PACKED / IN U. S. A. FROM / CHANCE MICRO SHEET / MADE IN ENGLAND
on label of cover slips: ARTHUR H. THOMAS CO., PHILADELPHIA, PA.
Inscribedon tube: No. 286764
on magnification table: Leitz Microscope No. 286764
FunctionThis instrument permits work in crystallography, mineralogy, petrology, and general microscopy in transmitted, incident, and polarized light.
Historical AttributesThis instrument was owned by Dr. Benjamin Shaub, Smith College, Northampton, MA.
Primary SourcesE. Leitz, Inc., Leitz Polarising Microscopes and Accessories (New York: E. Leitz, Inc., 1936), 16-17.
ProvenanceDr. Benjamin Shaub, Smith College, Northampton, MA