Object StatementCircular slide rule with pouch, instruction booklets and leaflets, Gilson A-B, duplex, multi-cursor, metal / plastic / paper, made by Gilson Slide Rule Co, Stuart, Florida, United States of America, 1940
Physical DescriptionSlide rule, Gilson A-B, circular, duplex, multi-cursor, a double sided disk of white enamelled metal with a large central bolt that hold two pairs of cursors on either side. One side is called the "Atlas" Slide rule and the other is the "Binary" Slide Rule. It is housed in a leatherette sheath and comes with instruction booklets for both types. Included in an envelope (dated 1953) are leaflets for the two types of slide rules.
The Binary Slide rule side has multiple scales from the standard set arrayed around the circle of 63cm circumference (at the outer edge) for greater precision.
Scales are: from the outer ring: C, CI (C inverted), A, K, L, LL4, LL3, LL2, LL1, B, and then a set for machinists including scales in mm and 64ths of an inch.
The Atlas Side Rule has three scales on it: the outer one is effectively 62cm (20 inches) long, the main one is a long spiral giving a precision equivalent to a straight scale 18.24 metres (60 feet) long, and the inner scale appears to be use for counting rotations around the long coil.
MarksName on slide rule, on observe, in upper center, painted in black ' Atlas Slide Rule ', on reverse, in upper center, printed in black ' The Binary Slide Rule / Made in the USA / Copyrighted 1940 ' in small text.
Manufacturer and name on one instruction booklet, on cover, printed in black ' Instructions for using the Binary Slide Rule / Printed in U. S. A. / Gilson Slide Rule Co., Box 993, Stuart, Fla. / (Slide Rule Makers Since 1915) '. On second instruction booklet, printed in black ' Instructions for using the Atlas Slide Rule / Printed in U. S. A '.
Stamp, notes and address on envelope, in upper left corner ' After 10 days return to Gilson Slide Rule Co., Box 993, Stuart, FLA.', in upper center ' Stuart, FLA / 6 pm Apr 20, 1953 ', in lower center ' J. M. Fenton / 22 Vandon Court / Petty France / London, S.W.L, England. '.
White paper lable on pouch, handwritten in black ' Bromely 1983-9 '.