altazimuth theodolite
Date1760-1795
Inventory Number5224
ClassificationTheodolite
Subject
Maker
George Adams (I)
1709 - 1772
Maker
George Adams (II)
English, 1750 - 1795
Cultural Region
Place of Origin
Dimensions30.2 x 26 x 20.5 cm (11 7/8 x 10 1/4 x 8 1/16 in.)
Material
Bibliography
DescriptionThe base of the instrument is a compass. It has four quadrants of 90º each divided in degrees, and does not have a decorated compass card. On that same base, the bigger screw is used to rotate the telescope on a graduated scale 0-360º. Three verniers on three separate index arms permit precision readings of up to 3'. The smaller screw is used to secure these index arms in place.
Mounted on top of the compass is the Y-level telescope to make altitude measurements. A tangent screw moves it up and down on a graduated half circle. A vernier permits precision readings of up to 3'. The telescope can be removed and reversed back end, thus serving as a surveyor's level. The optics is still very good. Some screws have small pre-determined punched dots for dismantling purposes.
Mounted on top of the compass is the Y-level telescope to make altitude measurements. A tangent screw moves it up and down on a graduated half circle. A vernier permits precision readings of up to 3'. The telescope can be removed and reversed back end, thus serving as a surveyor's level. The optics is still very good. Some screws have small pre-determined punched dots for dismantling purposes.
In Collection(s)
Signedon vernier scale arm: G. ADAMS / Math.l Inst.t / Maker to His / MAJESTY / Fleet Street / LONDON
Curatorial RemarksThis is a case where it is difficult to ascertain which Adams made this instrument. The range of dates, however, is good since it is based on the signature.
XRF analysis of the metals was done by Katherine Eremin and Sara Schechner in August 2007.
FunctionThis is an instrument used in surveying to measure simultaneously the altitude and azimuth angle of a determined position.
ProvenanceDavid Wheatland purchased from Sotheby's, London, July 15, 1963 (lot 181), via Ernst Weil. Donated to CHSI February 1977.
Benjamin Cole
Date: 1720-1740
Accessories: sight vane (2), key (box)
Object number: 5253
William Cary
Date: 1789-1825
Accessories: small eyepiece (box)
Object number: 5230a
Andrew Yeates
Date: circa 1840
Accessories: case, second eyepiece, plumb bob
Object number: 5235
Buff & Buff Manufacturing Company
Date: circa 1905
Accessories: wood case; leather case; right-angle prism; plumb bob; oil flask; tripod (5174b)
Object number: 5174a
W. & L. E. Gurley
Date: ca. 1884
Accessories: solar attachment; case; level; green filter; sun shade; tripod (5163b)
Object number: 5163a
Buff & Buff Manufacturing Company
Date: circa 1910
Accessories: carrying case; sunshades (2); dust cap; trivet; tripod (5177b)
Object number: 5177a
W. & L. E. Gurley
Date: circa 1910
Accessories: carrying case; dust cap; small tool; sunshade; key; plumb bob chain; tripod (5176b)
Object number: 5176a
Frederic W. Lincoln Jr. & Company
Date: circa 1880
Accessories: carrying case; sunshade; dust cap; tripod (5164b)
Object number: 5164a
William J. Young & Sons
Date: 1870-1875
Accessories: carrying case; dust cap; sunshade; leather belt strap; tripod (5165b)
Object number: 5165a
See also/See also
