WEST LAFAYETTE , Ind. – A permanent display on the first floor of Purdue University’s Potter Engineering Center contains about 200 slide rules, ranging in length from a few inches to 7 feet, with some dating to the 19th century. The collection also includes slide rules belonging to four astronauts who are Purdue alumni – Neil Armstrong, Jerry Ross, Richard Covey, and Roy Bridges. Purdue alumnus Eugene Cernan, the last man to walk on the moon, also promised to contribute his slide rule to the collection.

William Oughtred invented slide rules in1632 based on previous work by Scottish mathematician John Napier and English mathematician Edmund Gunter.

There was a point in time when the slide rule was king,” said James Alleman, Ph.D., professor of civil engineering at Purdue, who began collecting the slide rules from alumni15 years ago. The collection includes slide rules made of metal, wood, bamboo, paper, and plastic. During a period of about 400years, anything anybody built that was of any magnitude would have required a slide rule.

There are a lot of human stories here. If these slide rules could talk – because of all the alumni who donated these things – I am sure they would each tell remarkable stories about projects they were used on.”