altazimuth theodolite
Date1789-1825
Inventory Number5230a
ClassificationTheodolite
Subject
Maker
William Cary
c. 1759 - 1825
Cultural Region
Place of Origin
Dimensions20.5 x 37 x 14 cm (8 1/16 x 14 9/16 x 5 1/2 in.)
instrument box: 21 x 29.7 x 16 cm (8 1/4 x 11 11/16 x 6 5/16 in.)
instrument box: 21 x 29.7 x 16 cm (8 1/4 x 11 11/16 x 6 5/16 in.)
Material
Accessoriessmall eyepiece (box)
DescriptionThe base of the instrument rotates horizontally on a graduated circle divided in 30' increments. Two verniers, in combination with a tangent screw, are added for precision reading. Moreover, a small microscopic lens can be positioned anywhere on the base to help read the fine engraved lines.
The compass is divided into the eight principal cardinal directions and it has a 0-360° graduated circle divided in one degree increments. No decoration is found on the compass card. A level, finally, is fixed on the base of the instrument. There is also a level on the telescope. The latter is mounted on a triangular support on which a graduated arc 90°-0-90° determines the angle of the instrument from the horizon. It has a vernier and a tangent screw for precision reading of altitude measurements.
Two small pins hold in place hook-like braces attached to the support, which can be removed to detach the telescopic tube and turn it back to front to make measurements. This instrument can thus be used as a Y-level.
The compass is divided into the eight principal cardinal directions and it has a 0-360° graduated circle divided in one degree increments. No decoration is found on the compass card. A level, finally, is fixed on the base of the instrument. There is also a level on the telescope. The latter is mounted on a triangular support on which a graduated arc 90°-0-90° determines the angle of the instrument from the horizon. It has a vernier and a tangent screw for precision reading of altitude measurements.
Two small pins hold in place hook-like braces attached to the support, which can be removed to detach the telescopic tube and turn it back to front to make measurements. This instrument can thus be used as a Y-level.
In Collection(s)
Signedon compass card: Cary London
FunctionThis is an instrument used in surveying to measure simultaneously the altitude and azimuth angle of a determined position.
ProvenanceDavid Wheatland purchased from F. & G. Staack, Camden, Maine, June 20, 1959. Donated to CHSI February 1977.
Buff & Buff Manufacturing Company
Date: circa 1905
Accessories: wood case; leather case; right-angle prism; plumb bob; oil flask; tripod (5174b)
Object number: 5174a
Troughton & Simms
Date: 1826-1840
Accessories: mahogany box, telescope and sight tube (5), magnifying lens (vernier)
Object number: 5321a
Troughton & Simms
Date: 1826-1840
Accessories: mahogany box, telescope and sight tube (5), magnifying lens (vernier)
Object number: 5321b
Andrew Yeates
Date: circa 1840
Accessories: case, second eyepiece, plumb bob
Object number: 5235
Benjamin Cole
Date: 1720-1740
Accessories: sight vane (2), key (box)
Object number: 5253
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
William Cary
Date: 1790-1820
Accessories: original mahogany box (lid warped with cracks in two places)
Object number: DW0281
John H. Temple
Date: 1850-1870
Accessories: carrying case; dust cap; leather straps; tripod (5166b)
Object number: 5166a
Fauth & Company
Date: 1874-1905
Accessories: bubble level
Object number: 1997-1-1808
See also/See also
