surveyor's compass
Date1850-1870
Inventory Number5202a
ClassificationSurveyor's Compass
Subject
Maker
Horace Minot Pool
1803 - 1878
Maker
H. M. Pool & Brothers
fl. 1840 - 1870
Maker
J. & H. M. Pool
fl. 1828 - 1878
Cultural Region
Place of Origin
Dimensions22.5 x 35.3 x 12.8 cm (8 7/8 x 13 7/8 x 5 1/16 in.)
blue board box: 25.4 × 40.6 × 20.6 cm (10 × 16 × 8 1/8 in.)
blue board box: 25.4 × 40.6 × 20.6 cm (10 × 16 × 8 1/8 in.)
Material
Accessoriestripod (5202b)
DescriptionThe brass instrument has two removable sighting vanes, which attach by means of knurled thumbscrews underneath. Both vanes have a narrow slit and four circular apertures. On one arm, there are crossed bubble levels, forming a "T".
The wind rose is silvered and bilevel. There are eight cardinal points with North marked by a five-pointed star and south with the maker's name. The points are reversed (running clockwise, N, NW, W, SW, S, SE, and NE). Degrees are engraved on the raised divided scale (0°-90°-0°-90°-0°), divided every 30' and labeled every 10°. Magnetic needle is blued and consists of a simple bar with a short cross. The pivot is jewelled. There is a needle brake operated by a thumb screw under the compass box.
The instrument has a tripod socket with a knurled locking screw.
The wind rose is silvered and bilevel. There are eight cardinal points with North marked by a five-pointed star and south with the maker's name. The points are reversed (running clockwise, N, NW, W, SW, S, SE, and NE). Degrees are engraved on the raised divided scale (0°-90°-0°-90°-0°), divided every 30' and labeled every 10°. Magnetic needle is blued and consists of a simple bar with a short cross. The pivot is jewelled. There is a needle brake operated by a thumb screw under the compass box.
The instrument has a tripod socket with a knurled locking screw.
Signedon wind rose: H. M. Pool. / EASTON MASS.
FunctionThe surveyor's compass is an instrument used in surveying (or in navigation in rare cases) to measure horizontal angles, what is called bearing or azimuth.
For a nice discussion of this intrument, see the following website.
For a nice discussion of this intrument, see the following website.
ProvenanceDavid Wheatland purchased from Saul Moskowitz, Marblehead, Massachusetts, November 16, 1972. Donated to CHSI February 2, 1977.
Charles Pool
Date: 1820-1835
Accessories: carrying case; ball-and-socket joint; extra needle; plumb bob; glass vial; brass plates
Object number: 5194
H. M. Pool & Brothers
Date: circa 1845
Accessories: tripod (5197b)
Object number: 5197a
J. Pool & Company
Date: circa 1850
Accessories: carrying case
Object number: 5200
H. M. Pool & Brothers
Date: 1853-1858
Accessories: belt grip; dial cover plate; lifter arm; carrying case
Object number: 5188
Chamberlain & Ritchie
Date: 1850-1854
Accessories: carrying case; tripod (5129b)
Object number: 5129a
Andrew Yeates
Date: circa 1840
Accessories: case, second eyepiece, plumb bob
Object number: 5235
George Adams (I)
Date: 1750-1772
Accessories: carrying case; cover plate (missing)
Object number: DW0687
See also/See also
