English-Style Sector

Description
This yellowed ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The lower arm is broken. The scales run from top to bottom on each arm. On one side, each arm has a sine scale, running from 10 to 80 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 3 to 45 degrees; log sine, running from 1 to 70 degrees; and logarithmic numbers, running from 1 to 10 twice. A double line separates these scales from the inner, diagonal set of scales. The top face of the instrument has a scale of equal parts that divides one foot into 100 increments and runs from 90 to 10. There is no maker's mark.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typically found on 18th-century English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 12 to 1 and divided to tenths of an inch. Compare to MA*321755, MA*333937, and 1985.0580.06.
This sector may have been used at the New York Meteorological Observatory in Central Park, established and directed by Daniel Draper from 1868 to 1911.
References: Christopher J. Sangwin, "Edmund Gunter and the Sector," January 21, 2003, http://web.mat.bham.ac.uk/C.J.Sangwin/Sliderules/sector.pdf; Robert S. Harding and Jeffrey L. Tate, "Draper Family Collection, ca. 1826–1936," Archives Center, National Museum of American History, http://amhistory.si.edu/archives/d8121.htm.
Location
Currently not on view
Currently not on view
Object Name
sector
date made
19th century
Physical Description
ivory (overall material)
brass (overall material)
Measurements
overall: .3 cm x 16 cm x 3.5 cm; 1/8 in x 6 5/16 in x 1 3/8 in
place made
United Kingdom: England
ID Number
MA*335351
accession number
304826
catalog number
335351
subject
Science & Mathematics
Mathematics
Sectors
Rule, Calculating
Sectors
See more items in
Medicine and Science: Mathematics
Sectors
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of John William Christopher Draper and James Christopher Draper
Additional Media

Visitor Comments

Add a comment about this object

**Please read before submitting the form**

Have a comment or question about this object to share with the community? Please use the form below. Approved comments will appear on this page and may receive a museum response (but we can't promise). Please note that we generally cannot answer questions about your own artifacts or tell you how much they are worth.

Have a question about anything else, or would you prefer a personal response? Please visit our FAQ or contact page.

Personal information will not be shared or result in unsolicited e-mail. See our privacy policy.

Image CAPTCHA
Enter the characters shown in the image.