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Abbe-Type Apertometer with Box, by C. Zeiss, Jena, c.1878

Inventory Number: 13838
Object Type: Object
Persons: Carl Zeiss (Maker (Signed by))
Date Created: c.1878
Place Created: Jena Germany Europe
Accession Number: 1970-101/part
Brief Description: A semi-circular block of glass is cut so that light entering from the edge is reflected upwards through a slivered spot and into the optical axis of the objective. Along the edge are two scales, one marked in degrees to 80, and one marked in numerical aperture to 1.5. A pair of metal riders are placed along this edge so they are just visible in the field of view, so giving a measure of the aperture. There is also a short tube with a positive lens and two threaded adapters that, according to a handwritten note, "enable it to be used with both the long & short tubes of the P & L . No. 1 stand bequeathed by Dr. Whittell."
See Carl Zeiss "Description of Professor Abbe's apertometer, with instructions for its use" JRMS (1878)  p. 19-22 and Ernst Abbe 'Some remarks on the apertometer'  JRMS (1880) p.20-31.  for his theory on numerical aperture.
Box: fitted mahogany
Primary Inscriptions: .1: "1.615 / Abbe's / Carl Zeiss Iena / Apertometer" .2: "R.M.S.No. 65" on both riders .3: "R.M.S.No 65" .5: "AGENT C BAKER 244 HIGH HOLBORN LONDON"
Provenance: Deposited by the Royal Microscopical Society with their collection.
Collection Group: Royal Microscopical Society Collection

There are no associated narratives.

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