Accession No

2395

Brief Description

excise rule by T. Webb, c.1800

Origin

3 Infirmary Street; St. James’s; Bristol; England

Maker

Webb. T

Class

calculating

Earliest Date

1800

Latest Date

1800

Inscription Date

Material

boxwood; metal (brass)

Dimensions

length 302mm; breadth 35mm; thickness 28mm

Special Collection

Provenance

Purchased from Harriet Wynter, London, England, 11/1978.

Inscription

‘T. Webb * Maker No. 3 Infirmy Street St James’s * BRISTOL *’ (one edge)

Description Notes

Boxwood slide rule with inlet brass gauging points.
Face A: single radius log scale begins on upper part of stock and continues on lower; marked ‘D’, divided 1 - 10, numbered 1, 1[.]1...2, 3, 3[.]1, 3[.]2, 4, 5...10; gauging points marked ‘WG’, ‘AG’, ‘MS’ and ‘MR’. Slide has single radius log scale marked ‘A’, divided 1 - 10, numbered 1, 1[.]1...2, 3...10; gauging points marked ‘W’ and ‘C’. Reverse of slide carries list of gauge points and conversion factors.
Face B: upper part of stock has single radius log scale marked ‘A’, divided 1 - 10, numbered by 1; gauge points marked ‘MB’ and one unmarked one. Slide has single raidus log scale 1 - [9.5], numbered by 1. Lower part of stock has inverted single radius scale divided [2.15] - [22.5], numbered 3, 4...10, 2[0]. Reverse of slide has three scales: first is scale of inches, divided [0] - 12, numbered by 1, subdivided to 0.1; second scale marked ‘Spheroid’, divided [0] - [7.5], numbered by 1, subdivided to 0.1; third scale marked ‘2d variety’, divided [0] - [6.5], numbered by 1, subdivided to 0.1.
Edge A: double radius log scale beginning on upper stock and continuing on lower, marked ‘Seg. Lyg’, divided [0.2] - 100, numbered 1, 2...10, 20...100. Slide has single radius log scale marked ‘B’, divided 1 - [9.5], numbered by 1. Reverse of slide carries conversion factors.
Edge B: double radius log scale beginning on upper stock and continuing on lower, marked ‘Seg. St.’ and ‘SS’, divided [0.8] - 100, numbered 1, 2...10, 20...100. Slide has single radius log scale marked ‘B’, divided [0.5] - 10, numbered by 1. Reverse carries tables of conversion factors (?).
Each slide is bound in brass at one end.

Condition fair (warped and marked in some places); complete.

References

Events