altazimuth theodolite
Date: 1760-1795
Inventory Number: 5224
Classification: Theodolite
Subject:
Maker: George Adams (I) (1709 - 1772)
Maker: George Adams (II) (English, 1750 - 1795)
Cultural Region:
Place of Origin:
Dimensions:
30.2 x 26 x 20.5 cm (11 7/8 x 10 1/4 x 8 1/16 in.)
Bibliography:
Adams of Fleet Street: Instrument Makers to King George III
Description:
The 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
FunctionThis is an instrument used in surveying to measure simultaneously the altitude and azimuth angle of a determined position.
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.
XRF analysis of the metals was done by Katherine Eremin and Sara Schechner in August 2007.