Accession No
2087
Brief Description
cylindrical slide rule by Stanley 1/4 20th C
Origin
Great Turnstile; London; England
Maker
Stanley
Class
calculating
Earliest Date
1900
Latest Date
1925
Inscription Date
Material
metal (brass); wood (mahogany); paper; cloth (baize)
Dimensions
length 435mm; diameter 89mm box length 456mm; breadth 115mm; height 103mm
Special Collection
Provenance
Donated by Grace Masters c/o A.F. Hoffler, England, 28/8/1975
Inscription
‘STANLEY Maker LONDON’ (bottom of movable section)
‘FULLER’S SPIRAL SLIDE RULE’ (top of movable section)
‘ENTD. STATS HALL’ (bottom of movable section)
‘STANLEY,
GREAT TURNSTILE
LONDON
ENGLAND.’ (paper label inside lid of box)
Description Notes
Brass cylinder with flared mahogany ends. Cylinder coated with varnished paper. Second larger cylinder moves up and down over main cylinder. Brass index attached to one end, and brass scale extending along length of cylinder, divided 0.02 - 0.98, numbered by 0.02. Mahogany handle is fixed to bottom end.
On outer cylinder: scale of equal numbers at top, divided 0 - 0.02, numbered by 0.001, subdivided to 0.0001. Below this a spiral log scale divided 100 - [1000], numbered by 1; 100 - 650 subdivided to 0.1, remainder subdivided to 0.2.
Inner cylinder carries conversion tables, table of natural sines, ‘rules for numbers of figures in the quotient’ and explanation of use for finding powers and roots.
Fitted mahogany box with brass hinges and hook fasteners, partially lined with blue baize; contains brass shield with angled rod (corroded) which is attached to the outside of the box and supports the handle of the rule.
Condition good; complete
References
Events
Description
This instrument is a cylindrical slide rule, a variation on the most common type, also shown in this drawer, and described below.
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.
Cylindrical slide rules allow calculations to be done that would otherwise require a linear slide rule of many times its length.
FM:43836
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