Chambers Seven-Figure Logarithms of numbers up to 100000. Editor: James Pryde. Published by WR Chambers Ltd, London & Edinburgh, 1965.
Up until the mid 1970’s before the advent of inexpensive hand-held personal electronic calculators, engineers would use either a slide rule (there are a number of slide rules in this collection), log tables or mechanical calculators (see this collection 1994/002 and 2015/008) to undertake their calculations.
A standard ten inch slide rule would generally produce results to two significant figures and where more accuracy was required it was possible to use a cylindrical slide rule (eg a Fuller’s slide rule (see this collection 1994/001)) which could provide results to four significant figures. Where more accuracy was required log tables (four- or seven-figure) or mechanical calculators were used. Mechanical calculators were manufactured to be operated either manually or electrically. With the coming of the hand-held personal electronic calculators the use of log tables, slide rules and mechanical calculators declined rapidly.
Stamped “for ROBERT H CUTHBERTSON & PARTNERS” on front and back endpapers. Price “5/6” (5s 6d) on front flyleaf.
Logarithms were used where a greater degree of accuracy was required in calculations than could be provided by a slide rule.