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Date: circa 1925

Inventory Number: 1998-1-1383

Classification: Slide Rule

Subject:

Cultural Region:

Place of Origin:

Dimensions:

0.2 × 16 × 16 cm (1/16 × 6 5/16 × 6 5/16 in.)

DescriptionSlide chart composed of three off-white paper discs and two clear celluloid (?) indicators (with indicating lines etched on their surfaces) joined at the center by a brass fastener. The largest disc is between two smaller discs; one indicator is on top of each smaller disc. The slide chart's markings were all written by hand.

Three scales are printed around the circumference of the face of the larger disc. Around one half of the outer circumference is an "F" scale, composed of two logarithmic scales (values 1 to 10) placed side by side. Around the other half of the outer circumference is an "L" scale, and carries values 0 to 1.15. Inside these two scales, and adjacent to the top smaller disc, is a logarithmic "G" scale with two sets of values. The values inscribed within circles range from 1 to 89; the other set of values descends (clockwise) from 89 to 1.

Three additional scales are printed around the circumference of the top smaller disc. Around one half of the outer circumference is a logarithmic scale, "H", with values ranging from .02 to 3. Just clockwise of the line for 3 is an additional line, labeled [infinity]. Around the other half of the outer circumference is a logarithmic "K" scale with two sets of values. The values inscribed within circles descend (clockwise) from 89 to 0; the other set of values range from 0 to 90. Near the beginning of the "K" scale is an arrow pointing outward, labeled "L". Printed inside the "H" scale is a "J" scale composed of two logarithmic scales (values 1 to 10) placed side by side. The left half of the "J" scale is also marked with a second set of values; these descend from 0.9 to 0.

Printed around the circumference of the back of the larger disc are three scales. The outermost scale, "A", has three sets of values. The values inscribed within circles range from 0 to 1.4. Those inscribed within squares range from 0 to 28. The remaining values range from 0 to 7.

Printed inside the "A" scale is an unlabeled scale carrying values from 0 to 2.645. The innermost scale on the back of the largest disc is a "B" scale with values ranging from 0 to 1.15.

Sex scales are printed around the circumference of the bottom smaller disc. Around half of the outer circumference is a "C" scale labeled with two sets of values. The values inscribed within circles decend (clockwise) from 90 to 0; the other values ascend from 0 to 90. Around the other half of the outer circumference is a "E" scale, with three sets of values. The values inscribed within circles range from 0 to .9. Those values inscribed within squares range from 0 to 18. The remaining values range from 0 to 4.5.

Printed inside the "C" and "E" scales is an unlabeled scale with values ascending from 0 to [pi]/2, then descending from [pi]/2 to 0. Inside this scale is are three very small unlabeled scales. The leftmost scale has values descending from 1.57 to 0. The center scale is marked with two sets of values. The values inscribed within circles descend from 90 to 0; the other values ascend from 0 to 90. The rightmost scale carries values from 0 to 1.57.

Three scales are printed around the circumference of the face of the larger disc. Around one half of the outer circumference is an "F" scale, composed of two logarithmic scales (values 1 to 10) placed side by side. Around the other half of the outer circumference is an "L" scale, and carries values 0 to 1.15. Inside these two scales, and adjacent to the top smaller disc, is a logarithmic "G" scale with two sets of values. The values inscribed within circles range from 1 to 89; the other set of values descends (clockwise) from 89 to 1.

Three additional scales are printed around the circumference of the top smaller disc. Around one half of the outer circumference is a logarithmic scale, "H", with values ranging from .02 to 3. Just clockwise of the line for 3 is an additional line, labeled [infinity]. Around the other half of the outer circumference is a logarithmic "K" scale with two sets of values. The values inscribed within circles descend (clockwise) from 89 to 0; the other set of values range from 0 to 90. Near the beginning of the "K" scale is an arrow pointing outward, labeled "L". Printed inside the "H" scale is a "J" scale composed of two logarithmic scales (values 1 to 10) placed side by side. The left half of the "J" scale is also marked with a second set of values; these descend from 0.9 to 0.

Printed around the circumference of the back of the larger disc are three scales. The outermost scale, "A", has three sets of values. The values inscribed within circles range from 0 to 1.4. Those inscribed within squares range from 0 to 28. The remaining values range from 0 to 7.

Printed inside the "A" scale is an unlabeled scale carrying values from 0 to 2.645. The innermost scale on the back of the largest disc is a "B" scale with values ranging from 0 to 1.15.

Sex scales are printed around the circumference of the bottom smaller disc. Around half of the outer circumference is a "C" scale labeled with two sets of values. The values inscribed within circles decend (clockwise) from 90 to 0; the other values ascend from 0 to 90. Around the other half of the outer circumference is a "E" scale, with three sets of values. The values inscribed within circles range from 0 to .9. Those values inscribed within squares range from 0 to 18. The remaining values range from 0 to 4.5.

Printed inside the "C" and "E" scales is an unlabeled scale with values ascending from 0 to [pi]/2, then descending from [pi]/2 to 0. Inside this scale is are three very small unlabeled scales. The leftmost scale has values descending from 1.57 to 0. The center scale is marked with two sets of values. The values inscribed within circles descend from 90 to 0; the other values ascend from 0 to 90. The rightmost scale carries values from 0 to 1.57.

Signedtop disc, center: COMPLEX SLIDE RULE / DESIGNED BY / W. L. EVERITT / UNIVERSITY OF MICHIGAN

FunctionFor solving mathematics problems, likely in connection with electrical engineering. Slide rules with logarithmic scales, like those (F through K) on the face of this slide chart, are used to solve multiplication and division problems, as well as problems involving squares, square roots, and multiple factors.

Curatorial RemarksEveritt received his master's from the University of Michigan in 1926.

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