Accession No
5402
Brief Description
slide rule in card slip case, by Maurice Damien, French
Origin
France
Maker
Damien, Maurice
Class
calculating
Earliest Date
Latest Date
Inscription Date
Material
metal (aluminium?); paper (card); plastic
Dimensions
case length 290mm; width 51mm; thickness 26mm
Special Collection
Provenance
part of a group of slide rules used by Denys Bliss inventer of the segmented skirt which is used in hovercraft all over the world.
Inscription
RÈGLE A CALCULUS MAURICE DAMIEN
MADE IN FRANCE (gold embossed on case)
UNIVERSAL RULE DAMIEN, MADE IN FRANCE S.P.15 .BTEE S.G.D.G. (printed on back of rule)
KK21 (stamped into verso of slide)
Description Notes
Cardboard slip case mended with sellotape containing metal slide rule with a plastic cursor moves along scale; black line for index itself. The cursor is in two pieces, having come unglued at a join.
Stock has bevelled edges, one numbered by centimeters1-27 divided to 1 subdivided to 1mm, the other by inches (0)-10 by 1 to 1/32ths.
Upper part of stock:
log scale 1-1000 divided 1,2,3...1(0),2(0),3(0)...100,2(00),3(00)...1000
log scale 0.8-100 numbered (0.)8,(0.)9,1,2,3,π,4,...10,20,...100
Slide has log scale 0.8-100, numbered (0.)8,(0.)9,1,2,3,π,4,...10,20...100
log scale reading from right to left 1-10, numbered 1,(1.)1,(1.)2...2,3,4...10
log scale reading left to right 0.9-11, numbered (0.)9,1,(1.)1,(1.)2...2,3,π,4...10, (1)1
verso of slide:
‘S’ (sine) 6-80 divided 6,7,...20,25...40,50...80
‘S&T’ 40’-530 numbered 40’, 50’, 10, 130...530
‘T’ (tan) 6-45, numbered 6, 7...20, 25...45
Lower part of stock:
log scale 0.9-11, numbered (0.)9,1,(1.)1,(1.)2...2,3,π,4...10, (1)1
equal spaced scale marked ‘Quot +1’ and ‘Prod -1’ 0-10 numbered by 1, subdivided to 0.02
Reverse of the rule is printed with physical data, constants and unit conversion factors- Relationship between units, density of some solids, density of some liquids, density of some gasses, breaking stress, coef. of linear expansion, british units.
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.
FM:46097
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