Accession No
6154
Brief Description
2 slide rules by Pickett & Eckel, 1959 (c).
Origin
Maker
Pickett & Eckel
Class
calculating
Earliest Date
1959
Latest Date
1959
Inscription Date
1959
Material
Hide (leather); plastic; metal
Dimensions
Length 228mm; width 74mm; height 33mm
Special Collection
Hookham collection
Provenance
Donated by an individual on or before 07/08/2007.
Inscription
‘Pickett’ (top of holder to larger rule)
‘Pickett
PAT.PEND’ (top of holder to smaller rule)
‘MODEL
N 1006-ES
TRIG’ (on movable part of smaller rule)
‘MODEL
N1010-ES
TRIG’ (on movable part of larger rule)
Description Notes
Two yellow, plastic-coated metal duplex slide rules, one half the size of the other. Perspex cursors. Both stored in leather holders, the larger one being reinforced with plastic.
6154.1: 150mm rule; model N 1006-ES Trig.
On one side: top scale marked Ln, divided 0 - 2.3, numbered by 0.1, subdivided 0.01; bottom scale on top slide (DF) and top scale on movable part (CF) are both divided π - 9 then 1 - π, numbered by 1, subdivided 0.05 in π - 5 and 1 - π and subdivided 0.1 elsewhere; bottom scale on movable part (C) and top scale on bottom slide (D) are both divided 1 -9, numbered by 1, subdivided 0.02 in 1 - 2, 0.05 in 2 - 5 and 0.1 elsewhere; bottom scale on bottom part marked L, divided 0 - 1, numbered by 0.1, subdivided by 0.005.
On other side: top scale (K) is divided 1 -9 three times; bottom scale on top slide (A) and top scale on movable slide (B) are both divided 1 - 9 two times; middle scale on movable slide is divided 6 - 45 (T) and also 6 - 90 (S); bottom scale on movable slide (C) and top scale on bottom slide are both divided 1 - 9, numebred by 1, subdivided 0.02 in 1 - 2, 0.05 in 2 - 5 and 0.1 elsewhere.
6154.2: 3000mm rule; model N 1010-ES Trig.
On one side: top scale (DF) and top scale on movable part (CF) are both divided π - 9 then 1 - 9 then 2 - π; bottom scale on movable slide (C) and top scale on bottom slide (D) are both divided 1 -9 then 2 - 9, numbered by 1; bottom scale (L) is divided 0 - 1, numbered by 0.1.
On other side: top scale (K) divided 1 -9 three times; bottom scale on top slide (A) and top scale on movable slide (B) are both divided 1 - 9 two times; middle scale on movable slide is divided 6 - 45 (T) and also 6 - 90 (S); bottom scale on movable slide (C) and top scale on bottom slide are both divided 1 - 9, numebred by 1, subdivided 0.02 in 1 - 2, 0.05 in 2 - 5 and 0.1 elsewhere.
Good condition.
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.
Calculations are determined by aligning a point along the central movable strip with a mark on one of the scales on one of the two fixed strips, and then observing the relative positions of other points along the scales. 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). Moving the top scale to the right by a distance of log(x) aligns each number y, at position log(y) on the top scale, with the number at position log(x) + log(y) on the bottom scale. Because log(x) + log(y) = log(xy), this position on the bottom scale gives xy, the product of x and y.
Scales A and B are two-decade logarithmic scales used to find square roots and squares of numbers. Scales C and D are single-decade logarithmic scales. Scale K is a three-decade logarithmic scale usde for finding cube roots and cubes of numbers. CD and DF are ‘folded’ versions of the C and D scales, starting from π rather than unity, thus simplifying multiplying or dividing with π. DI is an inverted D scale, running from right to left to simplify 1/x steps. Scale S is used for finding sines and cosines on the D scale, and scale T for finding tangents on the D scale and cotangents on the DI scale. L is a linear scale used along with the C and D scales for finding base-10 logarithms and powers of 10.
07/08/2007
Created by: S Davis on 07/08/2007
FM:45070
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