brass protractor
Datecirca 1740
Inventory NumberDW0731
ClassificationProtractor
Subject
Maker
French
?
Cultural Region
Dimensionsinstrument: 0.5 × 31.8 × 8.3 cm (3/16 × 12 1/2 × 3 1/4 in.)
case: 1.9 × 34.3 × 10 cm (3/4 × 13 1/2 × 3 15/16 in.)
case: 1.9 × 34.3 × 10 cm (3/4 × 13 1/2 × 3 15/16 in.)
Material
Accessoriesfitted case with embossed leather exterior and coarse canvas interior
DescriptionThe protractor is stored in a leather embossed case with coarse canvas interior lining. The case is shaped like the compass with a long skinny neck and half-bulbous body. The interior is contoured to fit the instrument. The case is held closed with two brass hooks on the bottom edge of the case that fit into two brass loops on the top edge of the case.
The protractor consists of a brass half circle. The curved edge of the protractor is marked with three adjacent degree scales. The outermost scale has 180 engraved lines, one for each degree. The second scale has an engraved line every five degrees, and the innermost scale has an engraved line for every ten degrees and an engraved numeral, beginning with 180 degrees and decreasing in tens to 10 (0 is not marked with a numeral). There are two brass crossbars, one connecting the 155 degree mark to the 125 degree mark and another from the 180 degree mark to the 0 degree mark. There is a long, pivoting brass arm attached to the center of the latter crossbar. It is unmarked with some ornamental contouring at each end.
The protractor consists of a brass half circle. The curved edge of the protractor is marked with three adjacent degree scales. The outermost scale has 180 engraved lines, one for each degree. The second scale has an engraved line every five degrees, and the innermost scale has an engraved line for every ten degrees and an engraved numeral, beginning with 180 degrees and decreasing in tens to 10 (0 is not marked with a numeral). There are two brass crossbars, one connecting the 155 degree mark to the 125 degree mark and another from the 180 degree mark to the 0 degree mark. There is a long, pivoting brass arm attached to the center of the latter crossbar. It is unmarked with some ornamental contouring at each end.
Signedunsigned
FunctionProtractors are mathematical instruments used to measure and plot angles. In each case, the center of the 180 degree to 0 degree crossbar must be aligned with the vertex of the angle in question. The pivoting brass arm can be used as a rule when plotting an angle edge, or as a measurement aide, when aligned with an angle edge.
ProvenanceDavid Wheatland purchased from Lorenzo Paolozzi, Rome, Italy, September 1954 (#12). Donated to CHSI August 17, 1988.
Keuffel & Esser Company
Date: 1900-1950
Accessories: original cardboard sleeve case
Object number: 1997-1-1625
Elliott Brothers
Date: 1855-1870
Accessories: mahogany storage case lined with blue velvet
Object number: DW0460
French
Date: 1700-1750
Object number: DW0656
Walter Balcke
Date: 1952-1964
Accessories: mahogany box; cardboard instruction card
Object number: 1997-1-1601
Walter Balcke
Date: 1952-1964
Accessories: mahogany case; two circular protractors; clear plexiglass rule with serated edge
Object number: 1990-5-0028
Charles W. Dixey
Date: circa 1830
Accessories: silver framed green shagreen case
original curatorial cards and photos
Object number: DW0288
Gabriel & Edward Davis
Date: 1830-1850
Accessories: circular mahogany case with one straight edge
Object number: DW0386
