Abney reflecting level and clinometer
Date: circa 1910
Inventory Number: 5116
Classification: Level
Maker: Troughton & Simms (1826 - 1923)
User: Department of Geology and Geography, Harvard University (1890 - 1961)
Cultural Region:
Place of Origin:
Dimensions:
5.5 × 12 × 2.5 cm (2 3/16 × 4 3/4 × 1 in.)
case: 13.5 × 7 × 4 cm (5 5/16 × 2 3/4 × 1 9/16 in.)
Accessories: rectangular brown leather case with strap
DescriptionBrass sighting tube with clinometer and bubble level attached.
The sighting tube is square in cross-section, with a round eyepiece with knurling. There is a brass pin at the opposite end of the tube.
Bolted to the left side of the tube is a semicircular clinometer. The scales are in exposed brass. The outer scale has values descending from 60 to 0, then ascending from 0 to 60. The shorter, inner scale has values ranging from "1TO1" to 10.
Attached to the top center of the clinometer is a three-piece construction consisting of a wheel, a hanging vernier scale, and a spirit level.
The wheel and the hanging scale are on the scale side of the clinometer. The scale, with values descending from 60 to 0, then ascending from 0 to 60, meets the lower scale on the clinometer to form a vernier scale.
The spirit level tube sits on top of a level bar against the opposite side of the clinometer. The tube has a single oval window with a line down its center. There is an exposed brass pin at either end of the spirit level tube. A mirror in the sighting tube, visible through an oval cutout directly below the spirit level tube, allows the user to see the position of the bubble through the sighting tube.
The instrument is stored in a rectangular brown leather case. The flap closure is held shut by a brass knob on the body of the case. The case is accompanied by a leather strap with a brass buckle.
The sighting tube is square in cross-section, with a round eyepiece with knurling. There is a brass pin at the opposite end of the tube.
Bolted to the left side of the tube is a semicircular clinometer. The scales are in exposed brass. The outer scale has values descending from 60 to 0, then ascending from 0 to 60. The shorter, inner scale has values ranging from "1TO1" to 10.
Attached to the top center of the clinometer is a three-piece construction consisting of a wheel, a hanging vernier scale, and a spirit level.
The wheel and the hanging scale are on the scale side of the clinometer. The scale, with values descending from 60 to 0, then ascending from 0 to 60, meets the lower scale on the clinometer to form a vernier scale.
The spirit level tube sits on top of a level bar against the opposite side of the clinometer. The tube has a single oval window with a line down its center. There is an exposed brass pin at either end of the spirit level tube. A mirror in the sighting tube, visible through an oval cutout directly below the spirit level tube, allows the user to see the position of the bubble through the sighting tube.
The instrument is stored in a rectangular brown leather case. The flap closure is held shut by a brass knob on the body of the case. The case is accompanied by a leather strap with a brass buckle.
Signedengraved on sighting tube near eyepiece: TROUGHTON & SIMMS / LONDON
FunctionFor use in calculating the angle of depression or elevation between two points.
The user stands at one point and sights a rod target or other indicator atthe second point. Then he turns the wheel until the spirit level's bubble, as viewed through the sighting tube, is centered. The corresponding reading on the clinometer gives the angle of depression or elevation.
The user stands at one point and sights a rod target or other indicator atthe second point. Then he turns the wheel until the spirit level's bubble, as viewed through the sighting tube, is centered. The corresponding reading on the clinometer gives the angle of depression or elevation.
ProvenanceFrom Harvard University's Geology Department, January 17, 1967.