File:Typographical slide rule.jpg

White plastic typographical slide rule. On front rule shows text in different point sizes and reads 'the typographical slide rule is indispensable to all who are engaged in the printing and publishing trades on account of its ability to carry out all types of typographical calculations'. On the reverse there are various measures with a moveable central rule to show different calculations to the printer.

Accession Number: SH.2009.399

Slide rules were used extensively in many industries prior to the advent of portable handheld electronic calculating devices. Slide rules provided quick and accurate calculations for sophisticated mathematical problems.

This object was used by printers to calculate the size and weight of stock needed for particular jobs in relation to the number of words per page and the spacing and font size. This process was called cast off - the calculation of the extent of a book; the number of pages required to print a text in a certain typeface and point size, done by counting the characters and spaces

This slide rule was made by Faber-Castell. A.W Faber were a German company who began making slide rules in 1882, Celluloid covered wooden rules appeared after 1897. The company changed to Faber-Castell in 1906 and continued production of slide rules until 1976.

This rule was used at Holmes McDougall. The Holmes McDougall Group were based at Allander House, 137 - 141 Leith Walk. They were primarily educational publishers concerned with the publication of high quality primary and secondary educational books for use in schools both in the UK and abroad. The company slogan was 'The Teachers' Publisher'. The company had a magazine division based in Glasgow which published weekly and monthly titles including the Scottish Farmer, Climber and Rambler, The Great Outdoors, Business Scotland and the Scottish Field.