Nachet large petrographic compound microscope
Datecirca 1885
Inventory Number1202
ClassificationMicroscope
Subject
Maker
A. Nachet
1880 - 1890
User
John Eliot Wolff
1857 - 1940
Cultural Region
Place of Origin
Dimensions41 x 13.5 x 17 cm (16 1/8 x 5 5/16 x 6 11/16 in.)
Material
AccessoriesFixed (?) ocular with crosshairs; flip analyzer in tube; standard 11.5 x 0.45 mm objective No. 5 , but in sliding mount; substage polarizer; no case.
DescriptionThis is a larger and better equipped instrument than the Nachet polarizing microscope (inv. 1206), but similar in principle.
The microscope has a horseshoe shaped foot of brass filled with lead. Two pillars support the inclining upper half of the microscope. At the back of the microscope's upper platform, there is a pillar that carries the top (ocular end) of the tube on a curved arm with rack and pinion. The tube has a square window which can be made to align with a similar window in the ocular. A hinged round mirror is attached to the exterior of the tube below the window. The analyzer prism is on an arm that permits it to be swung into or out of the lower part of the tube. There is also a slot to insert a wave plate.
The objective end of the tube is separately moved by its own rack and pinion attached to a smaller pillar. This pillar is topped by the precision screw for the fine focus. The pillar is fixed to the rear of the rotating stage, which causes the objective to rotate together with the stage.
The microscope has a rotary stage with silvered divided circle and vernier. On top of the rotary stage is a graduated x-y mechanical stage. A polarizer is below the stage. The substage mirror is plano-concave and fork-mounted on an articulated arm attached to the underside of the upper platform of the microscope.
The polarizer, analyzer and the ocular do not rotate with respect to the stand. Specimen and objective thus keep their angular alignment while the plane of polarization is rotated.
The microscope has a horseshoe shaped foot of brass filled with lead. Two pillars support the inclining upper half of the microscope. At the back of the microscope's upper platform, there is a pillar that carries the top (ocular end) of the tube on a curved arm with rack and pinion. The tube has a square window which can be made to align with a similar window in the ocular. A hinged round mirror is attached to the exterior of the tube below the window. The analyzer prism is on an arm that permits it to be swung into or out of the lower part of the tube. There is also a slot to insert a wave plate.
The objective end of the tube is separately moved by its own rack and pinion attached to a smaller pillar. This pillar is topped by the precision screw for the fine focus. The pillar is fixed to the rear of the rotating stage, which causes the objective to rotate together with the stage.
The microscope has a rotary stage with silvered divided circle and vernier. On top of the rotary stage is a graduated x-y mechanical stage. A polarizer is below the stage. The substage mirror is plano-concave and fork-mounted on an articulated arm attached to the underside of the upper platform of the microscope.
The polarizer, analyzer and the ocular do not rotate with respect to the stand. Specimen and objective thus keep their angular alignment while the plane of polarization is rotated.
Signedon heel: NACHET / 17, rue St. Séverin / Paris
ProvenanceProfessor John Eliot Wolff (1857-1940), Department of Mineralogy and Petrography, Harvard University, from the 1880s onward; transfer to CHSI in 1969 courtesy of Professor Clifford Frondel.
Historical AttributesThis microscope was used by Professor John Eliot Wolff in the 1880s and 1890s. Wolff taught petrography and mineralogy at Harvard, first under the auspices of Chemistry and Geology and then as chair of the newly established Department of Mineralogy and Petrography from 1894 until his retirement in 1923. Wolff was also Curator of the Mineralogical Museum during those same years.
The instrument was transferred to CHSI in 1969 with the aid of Professor Clifford Frondel, a successor to Wolff as Curator of the Mineralogical Museum.
A. Nachet
Date: 1880-1890
Accessories: Ocular with crosshair; cap for ocular with analyzer; ocular cap; objective #3 with 11.5 x 045 mm threads; substage polarizer; no case.
Object number: 1206
Joseph Zentmayer
Date: circa 1875
Accessories: monocular body tube; 1 set of paired eyepieces; oculars (3); objective in canister: 8/10; wheel diaphragm; glass window; case; key.
Object number: 1073
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
E. Hartnack & A. Prazmowski
Date: circa 1870
Accessories: objectives (7): 1, 2, 4, 5, 7, 9,10 in fitted box ; eyepieces (4): 1, 4, 5, 6; cup diaphragms (4); polarizer set; bull's eye condenser on stand; Oberhaeuser-style camera lucida; tweezers; substage rotating wheel diaphragm attached to holder with blue glass filter; substage glass filter holder with blue glass filter; substage condenser; dual nosepiece, Hartnack 1/100 mm stage micrometer; flat case; key; magnification table; price lists (2).
Object number: 1080
Ernst Leitz (company)
Date: circa 1937
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)
Object number: 1999-1-0020a
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
Nachet et Fils (I)
Date: 1862-1880
Accessories: 5 objectives (11.5 mm) in leather-covered box (1025b): 1, 3, 5, 5, 7 immersion; 4 oculars: 1, 2, 3, no #; bull's eye on articulated stand (1025d); mahogany parts box (1025c with dissecting instruments: 6 needles, 2 scalpels, scissors, tweezers, 4 slides, box of cover glasses, 2 cup diaphragms, 1 diffuser ; flat case with fine lock, no key.
Object number: 1025a
Newton & Company
Date: circa 1860
Accessories: objective with canister: 1 inch; ocular; frog / fish plate; live box; mechanical stage; standing case
Object number: 1246
Boston Optical Works
Date: 1860-1890
Accessories: Three dated Tolles objectives: 1/2" Nov. 18, 1860, 1/4" Dec. 23, 1877, 1/5" Oct. 28, 1868; 1 high power solid eyepiece, 1 low power normal eyepiece; polarizer; substage mirror; mechanical stage, standing case.
Object number: 1066
Breton Frères
Date: circa 1850
Accessories: 6 convertible objectives; 4 nosepieces, one with polarizer; 4 oculars; black / white disk; spare round stage with offset diaphragm; camera lucida; light polarizing insert; compressorium by Chevalier; fish trough; 2 prepared slides; 3 cuvettes; brass box specimen holder with compressed slides and collar to attach to microscope; flat case.
Object number: 1274
Charles-Louis Chevalier
Date: circa 1840
Accessories: 2 convertible objectives: 1, 2, 3 and 0,00,000; 2 oculars; simple magnifiers: 3 and 5, with support bracket; extension pillar; bull's eye stage condenser on jointed arm; forceps; 3 prepared slides; box of cover glasses; 1/100 mm stage micrometer; camera lucida; tall bell jar; padlock on chain; case with key; table of magnifications
Object number: 1079
Andrew Pritchard
Date: 1835-1840
Accessories: objectives (4); oculars (6); lieberkühns (4); stage forceps; bull's eye condenser on stand; spring stage; extra mechanical stage; polarizer; cup diaphragms and holders; substage fork mount; live box; glass troughs (2); concave glass; fish tube holder; case; 2 keys. See also slide micrometers (2) (1088b,c)
Object number: 1088a