saccharimeter
Date1870-1880
Inventory Number1996-1-0584
ClassificationPolarimeter
Subject
Maker
J. G. Hofmann
fl. 1860 - 1880
Cultural Region
Place of Origin
Dimensions41 × 16.1 × 48.5 cm (16 1/8 × 6 5/16 × 19 1/8 in.)
Material
Bibliography
DescriptionThere are two tubes, one at the far end containing the polarizer (turned toward the light), and another at the near end with the analyzer and an eyepiece and cross hair reticule to look into. The polarizer was turned with a brass knob an amount which can be read off a vernier scale on the circular limb. The polariscope (analyzing tube) can be moved forward and back. In between the two there is a space to place a saccharimeter tube (the sliding cover, to make it a dark chamber, is missing).
According to a trade publication, the optics inside consisted of a) a polariscope eyepiece (made of a Nicol prism and an ocular lens); b) a polariscope objective (made of an objective lens); and c) a fringe polarizing tube (made of a polarizer and a lens for collecting light).
According to a trade publication, the optics inside consisted of a) a polariscope eyepiece (made of a Nicol prism and an ocular lens); b) a polariscope objective (made of an objective lens); and c) a fringe polarizing tube (made of a polarizer and a lens for collecting light).
Signedon instrument: J.G. Hofmann / Rue de Buci 3 / Paris
FunctionA saccharimeter is a polarimeter adapted for use with light source (sun or artificial, monochromatic or not), and it measures the optical activity of sugar solutions. The analyzer and polarizer (which are usually prisms) would be aligned such that no light passed through. Then the liquid substance was placed in between them, in a glass vial, and then put within a long glass tube (missing here). Light passing through the liquid creates fringes. The analyzer, close to the eyepiece, would be rotated until the fringes disappeared, and that angle would characterize the optical activity of the substance.
J. G. Hofmann marketed his instrument to sugar manufacturers so that they could test the quality of the plants they were buying. He also emphasized its use for diabetics and pointed out that it could be used to test the optical activity of any substance.
Hofmann built the first of his trademark polarimeters (called a polarimètre à franges because it involves the appearance and disappearance of colored fringes) in 1864. He claimed it required much less light than other (e.g. Soleil's) saccharimeter and therefore did not require the decoloration of the liquid in question.
J. G. Hofmann marketed his instrument to sugar manufacturers so that they could test the quality of the plants they were buying. He also emphasized its use for diabetics and pointed out that it could be used to test the optical activity of any substance.
Hofmann built the first of his trademark polarimeters (called a polarimètre à franges because it involves the appearance and disappearance of colored fringes) in 1864. He claimed it required much less light than other (e.g. Soleil's) saccharimeter and therefore did not require the decoloration of the liquid in question.
Hermann & Pfister
Date: circa 1872
Accessories: pine box; instruction manual; glass tubes (2); open-ended tube; gas lamp (DW0854b)
Object number: DW0854a
Félix Marie Pellin
Date: circa 1930
Object number: 1996-1-0365b
Ernst Leitz (company)
Date: circa 1919
Accessories: oculars (2): 3, 8x; accessory box; Leitz objectives (5); wrenches (2); ground glass; N.A. 1.45 condensor cap; Abbe condensor; rotary stage; case
Object number: 1345