Accession No
3012
Brief Description
two Hill’s slide rules, by Aston and Mander Ltd., English, 1/4 20th Century
Origin
England; London
Maker
Aston and Mander Ltd.
Class
calculating
Earliest Date
1900
Latest Date
1925
Inscription Date
1917
Material
plastic (ivorine and one other); metal (steel)
Dimensions
3012.1 length 176mm; width 51mm; 3012.2: length 180mm; breadth 51mm
Special Collection
Steward collection
Provenance
Collection purchased from member of the Steward family, 1974.
Inscription
‘ASTON & MANDER LTD MAKERS LONDON’ (obverse of 3012.1)
‘ASTON & MANDER 1917 LTD.’ (reverse of 3012.2)
‘HILL’S SLIDE RULE’ (reverse of both)
Description Notes
Two rectangular white plastic slide rules bound with steel screws.
Obverse: top half of stock carries scale of yards 3012.1 divided 100 - 7000, numbered 100, 200...1000, 2000, 3000...7000; 3012.2 divided 100 - 12000, numbered 100, 200...1000, 1500, 2000, 3000...12000. Slide carries three scales: first is degree scale divided 5´ - 8˚, numbered 5´, 10´...40´, 50´, 1˚, 1˚ 30´, 2˚, 3˚...8˚; second scale divided 1 - 90 and back to 160 (equivalent to 20), numbered 1, 2...10, 15, 20, 30...90, 90, 120, 140, 150, 160; third scale for 3012.1 divided [0] (?) - 80 numbered 20, 30 ... 70, 75, 80; third scale for 3012.2 divided 10˚ - [80˚], numbered 10, 15, 20, 30...70. Lower part of stock carries scale of yards divided 5 - 300 numbered 5, 10, 15, 20, 30 ... 100, 200, 300 (150 marked on 3012.2); 100 - 300 subdivided to 10. 3012.2 also has scale divided 5˚ - 80˚, numbered 5, 10, 20...70, 75, 80, subdivided to 5˚.
Reverse: scale marked ‘800x’ divided 1 - 14 numbered by 1. Also range tables for ‘18 pounder Q.F.’ and list of ‘orders’.
Condition good; 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:42299
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