brass surveyor's cross with compass
Date: late 19th century
Inventory Number: DW0265
Classification: Surveyor's Cross
Subject:
Maker: French ?
Cultural Region:
Dimensions:
19 × 9.2 × 9.2 cm (7 1/2 × 3 5/8 × 3 5/8 in.)
box: 10.9 × 21.5 × 12 cm (4 5/16 × 8 7/16 × 4 3/4 in.)
Accessories: mahogany box with brass hook closure and brass handle
DescriptionBrass surveyor's cross with staff mount and compass, probably French.
The body of the cross is composed of two drums. The bottom drum is approximately half as tall as the top drum. Around the bottom edge of the top drum and the top edge of the bottom drum are silver scales, together forming a vernier scale. The top drom has four vertical slits around its circumference; the bottom drum as two slits opposite one another. The position of the drums relative one another is changed by rotating a circular knurled knob projecting down from the bottom drum.
On top of the top drum is a brass compass with a black face and silver needles. The silver ring around the circumference of the compass is engraved with a scale ranging from 0 to 360. The face of the drum is marked with a cross, with the cardinal points labeled (N, E, S, O). Extending out radially between the marks for east and south is a gold or brass bar. The compass is secured to the top of the top drum by a brass pin through a rectangular slit in the side of the compass.
Projecting down from the bottom drum is a staff mount with a flared, knurled bottom. Stamped just above the base of the mount is the number 2.
The surveyor's cross is stored in a mahogany box with brass hook closures and a brass handle. The inside of the lid of the box is cracked.
The body of the cross is composed of two drums. The bottom drum is approximately half as tall as the top drum. Around the bottom edge of the top drum and the top edge of the bottom drum are silver scales, together forming a vernier scale. The top drom has four vertical slits around its circumference; the bottom drum as two slits opposite one another. The position of the drums relative one another is changed by rotating a circular knurled knob projecting down from the bottom drum.
On top of the top drum is a brass compass with a black face and silver needles. The silver ring around the circumference of the compass is engraved with a scale ranging from 0 to 360. The face of the drum is marked with a cross, with the cardinal points labeled (N, E, S, O). Extending out radially between the marks for east and south is a gold or brass bar. The compass is secured to the top of the top drum by a brass pin through a rectangular slit in the side of the compass.
Projecting down from the bottom drum is a staff mount with a flared, knurled bottom. Stamped just above the base of the mount is the number 2.
The surveyor's cross is stored in a mahogany box with brass hook closures and a brass handle. The inside of the lid of the box is cracked.
Signedunsigned
Inscribedstamped above the base of the mount: 2
FunctionA surveyor's cross is used to establish straight lines and to lay out grids and perpindicular angles while surveying. It can also be used to take more complicated measurements, using the theory of similar triangles.
To find the distance between the line between two points and a third point, the cross, on a staff, is taken between the first two points and adjusted until these are sighted through two slits on the top drum. The staff is then moved up and down the line between the first two points until the third point is visible through the perpindicular slits on the top drum. The distance from the staff to the third point may then be measured.
For more on the use of the surveyor's cross, see this article in the magazine Professional Surveyor.
To find the distance between the line between two points and a third point, the cross, on a staff, is taken between the first two points and adjusted until these are sighted through two slits on the top drum. The staff is then moved up and down the line between the first two points until the third point is visible through the perpindicular slits on the top drum. The distance from the staff to the third point may then be measured.
For more on the use of the surveyor's cross, see this article in the magazine Professional Surveyor.
ProvenanceAcquired by David P. Wheatland in Paris.