POWERHOUSE COLLECTION

Faber Castell 2/82 N Biplex slide rule

Object No. 2010/1/332

Over the 19th and much of the 20th centuries the slide rule was the primary instrument for calculation used by many people engaged in the trades and in engineering. Although originally invented in the 17th century, and widely used for gauging (or estimating the quantities of certain products such as alcoholic spirits) it took until around 1850 for the slide rule to become generally popular with those for whom mathematics was a daily task. This was largely brought about through the increase in accuracy made possible by the development of the dividing engine and Amédée Mannheim's 1850 standardisation of the arrangement of scales utilised. His scales were the "C" and "D" scales, ranging from 1 (the index) to 10 and used for multiplication and division, and the "A" and "B" scales, ranging from 1 (the index) to 100 and used for squares and square roots. New arrangements of scales appeared in the 20th century with the Rietz arrangement in 1902 and the Darmstadt arrangement in 1934. The Rietz scales added a log "L" scale, a "CI" or C inverted scale which was useful for calculations involving the reciprocal of a number, and the trigonometric scales: sine "S", tangent "T" and "ST" for the small angles were the sine and tangent are the same, to the front face of the stock. The Darmstadt arrangement added a series of Log-Log scales. This object is an example of a slide rule with a large number of scales and an extra wide body to accommodate them. It was specifically targeted at Engineers, Physicists and others for whom high level mathematical calculation was a regular task. It was manufactured from injection moulded plastic, known as Geroplast, and was made by Faber-Castell around 1962. Slide rules manufactured by A.W. Faber and Faber-Castell were among the best made and most successful slide rules of the 20th century. The Faber company began as a maker of lead pencils in 1761 and expanded during the following century until in 1862 the then head of the company Lothar Faber was made a peer by King Maximilian of Bavaria, becoming Lothar von Faber. At this time the A.W Faber Company began to expand their product range. Lead pencils remained their main product until, in 1882, they commenced the manufacture of wooden slide rules using the Mannheim scales, selling them in Germany, France, England and the United States. A.W. Faber stopped making slide rules in 1976 since the electronic calculator had taken over the market for hand-held calculating instruments. Refs: Peter Hopp, Slide Rules, their History, Models and Makers, Mendham, New Jersey: Astragal Press, 1999. http://www.answers.com/topic/a-w-faber-castell-unternehmensverwaltung-gmbh-co?cat=biz-fin - Company History: A.W. Faber-Castell Unternehmensverwaltung GmbH & Co. Time Line for A.W. Faber and Faber-Castell http://www.sliderulemuseum.com/SR_Dates.htm#Faber - Dieter von Jezierski, Slide Rules - A Journey Through Three Centuries (Astragal Press). Stephen Jones 30 January 2008