Carl Georg Barth

Carl Georg Lange Barth (February 28, 1860 – October 28, 1939) was a Norwegian-American mathematician, mechanical and consulting engineer, and lecturer at Harvard University.

[3] In 1899, efficiency expert Frederick W. Taylor hired Barth to work with him at Bethlehem Steel Company.

[4] Carl G. Barth... discovered the law governing the tiring effect of heavy labor... such work consists of a heavy pull or a push on the man's arms... For example, when pig iron is being handled (each pig weighing 92 pounds), a first-class workman can only be under load 43 per cent.

An account of their application of slide rules was published in the Transactions of the American Society of Mechanical Engineers in 1904.

[2] Barth edited articles submitted to International Correspondence School of Scranton, Pennsylvania publication, the Home Study Magazine.

Carl G. Barth, 1911.
One of Carl G. Barth's speed-and-feed slide rules