Accession No

0585

Brief Description

Hannyngton’s grid slide rule, by Aston and Mander, English, 19th Century

Origin

England; London; 25 Old Compton Street

Maker

Aston and Mander

Class

calculating

Earliest Date

1800

Latest Date

1900

Inscription Date

Material

wood (boxwood and two others); metal (white metal, brass); paper

Dimensions

length 793mm; breadth 196mm; thickness 25mm box length 820mm; breadth 220mm; height 45mm

Special Collection

Cavendish collection

Provenance

Hutchinson collection

Inscription

‘Arragned By Major General Hannyngton
Aston & Mander Sole Makers 25 Old Compton St. London. W.’ (underneath slide)
‘120-inch Rule’ (paper label inside box)

Description Notes

Boxwood scales set on black-painted wooden base. Multiple slide bound with white metal has 8 sections which slide between sections on the base. Stock has 11 sections of its scales; these are divided into two main scales, one running from 100 to 3150, the other from 134 to 2370. Stock scale marked ‘A’.
Slide scale marked ‘B’ and numbers run from 100 to 1020 but beginning of each scale overlaps the previous one.
Wooden box with brass hook fasteners and hinges.

Condition good (stock somewhat warped, box poor); complete.

References

Events

Description
Developed during the seventeenth century, the modern slide rule is based upon the design by William Oughtred (circa 1630). It is one of many calculation devices that is based on the logarithmic scale, a calculation method invented in 1614 by John Napier.

Before the rise of the pocket electronic calculator in the 1970s, the slide rule was the most common tool for calculation used in science and engineering. It was used for multiplication and division, and in some cases also for ‘scientific’ functions like trigonometry, roots and logs, but not usually for addition and subtraction.

A logarithm transforms the operations of multiplication and division to addition and subtraction according to the rules log(xy) = log(x) + log(y) and log(x/y) = log(x) - log(y). The slide rule places movable logarithmic scales side by side so that the logarithms of two numbers can be easily added or subtracted from one another. This much simplifies the alternative process of looking up logs in a table, thus greatly simplifying otherwise challenging multiplications and divisions. To multiply, for example, you place the start of the second scale at the log of the first number you are multiplying, then find the log of the second number you are multiplying on the second scale, and see what number it is next to on the first scale.

FM:42158