Troughton & Simms dumpy level
Datecirca 1830
Inventory Number5208a
ClassificationSurveyor's Level
Subject
Maker
Troughton & Simms
1826 - 1923
Cultural Region
Place of Origin
Dimensionslevel: 19.7 × 12.2 × 37 cm (7 3/4 × 4 13/16 × 14 9/16 in.)
case: 12 × 48.7 × 14.9 cm (4 3/4 × 19 3/16 × 5 7/8 in.)
case: 12 × 48.7 × 14.9 cm (4 3/4 × 19 3/16 × 5 7/8 in.)
Material
Accessoriesmahogany case with brass hooks and hinges, and felt protectors; additional eyepiece; magnifier; adjustable mirror; tripod mount; foot plate (5208b); tripod (5208b)
DescriptionBrass dumpy level with the following major components (top to bottom): one large and one small spirit level; telescope tube; and compass.
The large spirit level, which is bolted to the top of the telescope tube, has two oval glass windows. Each window is printed with an unlabeled scale having twenty-five divisions. Each scale starts some distance in from the window's inner edge.
The small spirit level is mounted crosswise on a U-shaped brass plate extending from one of the large level's mounts. It has a single oval glass window.
The telescope tube has knurling around the eyepiece and the two ends of the larger portion of the tube. Near the eyepiece are two brass pins with holes in them, projecting out from the tube opposite one another. Beside one of the pins is a series of slits, each with a circular hole at one end. The objective end of the telescope has a pivoting brass cover. The telescope itself is mounted on two brass blocks on the level bar.
Also mounted on the level bar, between these blocks, is a compass with a black face. Overlapping the needle's tips is a silvered floating pivot ring, which can be released by turning a knurled knob projecting below the compass. Engraved on the ring is a scale with values ranging from 0 to 360 (clockwise), graduated into ones and halves. Bolted to the side of the compass ring is a brass loop which may be used to mount a small magnifying glass.
Attached to the dumpy level as shown is a brass tripod mount not original to this instrument. The mount is conical, with two wide textured rings near its bottom edge.
The instrument is stored in a mahogany case with brass hooks and hinges, and felt protectors. Also in the case are a magnifier for the compass, an additional eyepiece, and an adjustable mirror for use in reading the bubble level.
The large spirit level, which is bolted to the top of the telescope tube, has two oval glass windows. Each window is printed with an unlabeled scale having twenty-five divisions. Each scale starts some distance in from the window's inner edge.
The small spirit level is mounted crosswise on a U-shaped brass plate extending from one of the large level's mounts. It has a single oval glass window.
The telescope tube has knurling around the eyepiece and the two ends of the larger portion of the tube. Near the eyepiece are two brass pins with holes in them, projecting out from the tube opposite one another. Beside one of the pins is a series of slits, each with a circular hole at one end. The objective end of the telescope has a pivoting brass cover. The telescope itself is mounted on two brass blocks on the level bar.
Also mounted on the level bar, between these blocks, is a compass with a black face. Overlapping the needle's tips is a silvered floating pivot ring, which can be released by turning a knurled knob projecting below the compass. Engraved on the ring is a scale with values ranging from 0 to 360 (clockwise), graduated into ones and halves. Bolted to the side of the compass ring is a brass loop which may be used to mount a small magnifying glass.
Attached to the dumpy level as shown is a brass tripod mount not original to this instrument. The mount is conical, with two wide textured rings near its bottom edge.
The instrument is stored in a mahogany case with brass hooks and hinges, and felt protectors. Also in the case are a magnifier for the compass, an additional eyepiece, and an adjustable mirror for use in reading the bubble level.
Signedengraved on side of telescope tube: Troughton & Simms, London
Curatorial RemarksTwo glossy black and white photographs of instrument in instrument file, 5208a&b. Also in file is handwritten information on tripod adaptation.;
This object was previously numbered DW0198.;
See another Troughton & Simms dumpy level, 5208a.
FunctionFor use in surveying, to measure contours.
After mounting the dumpy level on a tripod (see 5208b) at his starting location, the user levels the instrument by means of the spirit levels and the leveling screws (5208b). Then he sights a stadia rod through the telescope, moving the rod as needed until the target is centered behind the telescope's cross hairs. The difference in height between the telescope and the rod target indicates the gain in elevation over the horizontal distance between the two.
The compass attached to the level bar may be used to indicate direction of measurement, or to calculate horizontal angles.
Attached to the dumpy level as shown is a brass tripod mount not original to this instrument.
After mounting the dumpy level on a tripod (see 5208b) at his starting location, the user levels the instrument by means of the spirit levels and the leveling screws (5208b). Then he sights a stadia rod through the telescope, moving the rod as needed until the target is centered behind the telescope's cross hairs. The difference in height between the telescope and the rod target indicates the gain in elevation over the horizontal distance between the two.
The compass attached to the level bar may be used to indicate direction of measurement, or to calculate horizontal angles.
Attached to the dumpy level as shown is a brass tripod mount not original to this instrument.
ProvenanceDavid Wheatland purchased from Margaret Zervas, Long Island, NY, October 25, 1966. Donated to CHSI February 1977.
Troughton & Simms
Date: circa 1840
Accessories: mahogany box with brass hinges and hooks
Object number: 5232
Herman E. Fessel
Date: circa 1870
Accessories: mahogany case; sunshade; dust cover; tripod (5145b)
Object number: 5145a
P. & R. Wittstock
Date: circa 1900
Accessories: mahogany case; 2 sunshades; dust cover
Object number: 5146a
Keuffel & Esser Company
Date: circa 1909
Accessories: mahogany case with brass corner protectors and lock; key; sunshade; dust cover; tripod (5147b)
Object number: 5147a
Frederick Eckel
Date: circa 1885
Accessories: mahogany case (top very worn); lens hood; sunshade; tripod, see 5151b
Object number: 5151a
Peter & John Dollond
Date: 1780-1800
Accessories: mahogany box with brass hooks, hinges, and handle; tripod (see 5240b)
Object number: 5240a
Buff & Berger
Date: circa 1880
Accessories: mahogany case; sunshade; screws; dust cover; tripod (5144b)
Object number: 5144a
Adie & Son
Date: circa 1850
Accessories: case; dust cap and sunshade; eyepiece
Object number: 5209
Iszard-Warren Co., Inc.
Date: circa 1910
Accessories: mahogany case with brass corners and lock; key missing; leather strap; screwdriver; dust cover; sunshade; tripod, see 5150b
Object number: 5150a
John H. Temple
Date: circa 1870
Accessories: mahogany case; sunshade; tripod (5142b)
Object number: 5142a
Buff & Berger
Date: circa 1890
Accessories: mahogany case with lock (key not found); leather strap; screwdriver; dust cover; sunshade; tripod, see 5149b
Object number: 5149a
