Robertson slide rule
Datecirca 1805
Inventory Number0067
ClassificationSlide Rule
Subject
Maker
W. & S. Jones
fl. 1791 - 1859
User
John Farrar
1779 - 1853
Cultural Region
Place of Origin
Dimensions82.6 x 6.5 x 1.1 cm (32 1/2 x 2 9/16 x 7/16 in.)
Material
Bibliography
DescriptionThis slide rule is in the shape of a long rectangle and is made of fruit wood. Its grooved central slide is held together at both ends by riveted brass clamps. The slide is fitted with two precision adjusting screws. The number of graduated lines is large: A, B, C, D, CF, DF, CI, K, S, T, SRUM, TRUM, VBIN, SIN, NUM, TAN, MER, MD, DL, CHO, STAN.
Another set of lines is called Gunter's scale. It was a set of lines designed by Edmund Gunter in the seventeenth century to perform any number of calculations with logarithms. Following Gunter's design, the logarithmic scale was often used in navigation, where it facilitated calculations of spherical triangles.
This slide rule also has a moving cursor or index, which was introduced in the second half of the eighteenth century by John Robertson, Librarian for the Royal Society.
Another set of lines is called Gunter's scale. It was a set of lines designed by Edmund Gunter in the seventeenth century to perform any number of calculations with logarithms. Following Gunter's design, the logarithmic scale was often used in navigation, where it facilitated calculations of spherical triangles.
This slide rule also has a moving cursor or index, which was introduced in the second half of the eighteenth century by John Robertson, Librarian for the Royal Society.
In Collection(s)
Signedengraved on brass end clip: W & S Jones / 30 Holborn London
FunctionThe slide rule did not generally perform addition or subtraction. It was rather used to perform multiplication and division, or any other "scientific" functions such as roots, logarithms, and especially trigonometry. This particular slide rule was outfitted with graduated lines that emphasized its use in navigation.
ProvenanceHarvard College, 1805 purchase.
Historical AttributesIn W & S Jones's catalogue of 1822 one can read: "[Gunter's] Three-foot ditto [sliding navigation scales] improved by Robertson, with brass adjusting screws, &c. being the completest scale of the kind. [price] 1 15 0."
This is the same price Harvard paid when it received this particular slide rule in 1805, which was labeled in the following way in the invoice: "An improved Robertson's gunters with improved adjusting screw–1.15.0".
The slide rule also appears in an inventory of apparatus of the Hollis professorship of mathematics and natural philosophy, taken in 1807 when John Farrar became Hollis professor.
Digital Equipment Corporation
Date: circa 1980
Object number: 1998-1-1042
English
Date: 1775-1800
Accessories: case contains the following nine instruments: one ivory and brass sector; one ivory and brass parallel rule; one brass protractor; two pairs of dividers, one with pen holder, pencil holder, and inking wheel (for drawing dotted line) attachments; and pen.
Object number: 5458