Beck Cheshire's apertometer
Datecirca 1907
Inventory Number1122d
ClassificationMicroscope Accessories
Subject
Maker
R. & J. Beck
1865 - 1920
Cultural Region
Place of Origin
Dimensionsmicroscope: 44 × 25 × 24 cm (17 5/16 × 9 13/16 × 9 7/16 in.)
case: 15.9 × 47 × 24.2 cm (6 1/4 × 18 1/2 × 9 1/2 in.)
case: 15.9 × 47 × 24.2 cm (6 1/4 × 18 1/2 × 9 1/2 in.)
Material
Accessorieseyepiece telescope to magnify image
DescriptionThis is a Beck "Small Best" convertible binocular-monocular compound microscope with a full complement of accessories. Due to the complexity, the objects have been divided into the following:
1122a: Beck convertible binocular-monocular microscope
1122b: Beck case with objectives, oculars, and common accessories
1122c: Beck patent revolving substage condenser
1122d: Beck Cheshire's apertometer
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The Cheshire's apertometer (1122d) consists of a series of semicircular concentric arcs ranging in size from smallest on the inside to largest at the outside. The arcs are numbered from the center 1-9 and then 0-5. The label reads "CHESHIRE'S APERTOMETER." They are printed on white paper housed underneath a thick disk of clear glass. The glass is held in a brass cylindricaL box with a screw-top lid.
A special eyepiece telescope could be used to magnify the image on the back of the objective. It looks very much like the erecting glass used with objectives found in the case of accessories (1122b).
1122a: Beck convertible binocular-monocular microscope
1122b: Beck case with objectives, oculars, and common accessories
1122c: Beck patent revolving substage condenser
1122d: Beck Cheshire's apertometer
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The Cheshire's apertometer (1122d) consists of a series of semicircular concentric arcs ranging in size from smallest on the inside to largest at the outside. The arcs are numbered from the center 1-9 and then 0-5. The label reads "CHESHIRE'S APERTOMETER." They are printed on white paper housed underneath a thick disk of clear glass. The glass is held in a brass cylindricaL box with a screw-top lid.
A special eyepiece telescope could be used to magnify the image on the back of the objective. It looks very much like the erecting glass used with objectives found in the case of accessories (1122b).
Signedon box lid: R & J. BECK. LTD.
FunctionTo test objectives in order to determine their numerical aperture (N.A.). The number of rings seen in the back lens of the objective gives the aperture in decimals, each ring being 0.1 N.A.
ProvenanceAlexander Agassiz, Marine Biological Laboratory, Newport, Rhode Island, c. 1876; Museum of Comparative Zoology, Harvard University, c. 1910; transfer by Thomas Barbour, MCZ Director to the Ernst-Lewis Collection of Microscopes (inv. no. 122), Harvard Medical School, May 18, 1936.
Historical AttributesThis Wenham-type binocular microscope by R. & J. Beck was Alexander Agassiz's personal instrument. It was used at his Marine Biological Laboratory in Newport, Rhode Island, where Agassiz summered. The instrument appears with Agassiz in a portrait that shows him working in this lab. Corrosion on parts of the microscope are probably due to contact with marine creatures and sea water.
This microscope was given to the Ernst-Lewis Collection on May 18, 1936 by Dr. Thomas Barbour, Director of the Museum of Comparative Zoology.
According to the correspondence between Conrad Beck, managing director of R. & J. Beck, and Dr. Frederic T. Lewis in 1939, the microscope is the type called the "Small Best" and was made in 1876. With all the accessories, it would have cost between £60 and £80.
R. & J. Beck
Date: 1876
Accessories: Beck patent substage condenser (1122c); apertometer (1122d)
Object number: 1122b
R. & J. Beck
Date: 1876
Accessories: oculars (2) in microscope; Darker's selenite retarding filters (3); wheel diaphragm; mechanical rotary stage; stage slider. Other accessories are in the case (1122b), including monocular draw tube; oculars (3); objectives in cans (5); empty can; Lieberkühn; polarizing set; slides; camera lucidas (2); etc.; plus a Beck patent substage condenser (1122c); and apertometer (1122d).
Object number: 1122a
R. & J. Beck
Date: circa 1878
Accessories: oculars (3); eye mask; Beck objectives with cans (2): 1, 1/6 in.; anonymous onjective: 1/15 in homog. im..; tweezers; triple nosepiece; Rousselet-type sliding stage; Abbe condenser; iris diaphgragm; cover slips (2); prescription envelope; instructions; lock parts; standing case with key.
Object number: 1362
Smith, Beck & Beck
Date: circa 1860
Accessories: complete set of approximately 50 accessories in two boxes [see early file card]
Object number: 1237
Bausch & Lomb Optical Company
Date: circa 1877
Accessories: B&L objectives (2); 1 ocular; camera lucida; eyepiece micrometer; slides (12 prepared; 2 plain); glass pipette; box of cover glasses; directions card; magnification card; case with key
Object number: 1056
Joseph Zentmayer
Date: circa 1880
Accessories: Zentmayer objective with cannister: 1 1/2; paired oculars (3); Bicknell's achromatic condenser; rotating wheel diaphragm; polarizing eyepiece, polarizer by objective; camera lucida; plane glass window and brass socket; monocular tube; parts box with key; standing case with key.
Object number: 1015
Smith & Beck
Date: circa 1850
Accessories: Achromatic condensor; a darkfield condenser (Wenham's parabolic reflector); a substage set of aperture stops on a swingaway vane inside a sleeve; a nickel tweezers; a stage forceps; and a bull's eye condenser with a stand, a glass tray for the stage, Varley live box; case.
Object number: 1059
R. & J. Beck
Date: circa 1885
Accessories: objectives (3); paired oculars
Object number: 1273
R. & J. Beck
Date: circa 1884
Accessories: oculars (2); double nosepiece; mahagony case with various parts (see description)
Object number: 1083
R. & J. Beck
Date: circa 1890
Accessories: paired oculars; objective 16mm ; analyzer in mount; polarizer in mount; mechanical stage
Object number: 1328