Improver and popularizer of the industrial use of compound slide rules in scientific management, Barth was a Norwegian-American mathematician and mechanical engineer. He was born in Christiania, Norway, and graduated from the University at Christiania. He later attended the Royal Norwegian Navy technical school at Horten. In 1877, he started an apprenticeship in the navy yard at Karljohansvern in Horten.
In 1899, efficiency expert Frederick W. Taylor hired him to work at Bethlehem Steel Company. Barth helped to develop speed-and-feed-calculating slide rules. In 1902, he and Taylor went to work for William Sellers at the machine tool firm of William Sellers & Company of Philadelphia. An account of their application of slide rules was published in the Transactions of the American Society of Mechanical Engineers in 1904.
In 1905, Barth embarked on his independent career as a consulting engineer and became an early consultant on scientific management, later teaching at Harvard University. He edited articles submitted to the International Correspondence School of Scranton, Pennsylvania publication, the Home Study Magazine. In 1909, he undertook the installation of scientific management in the Watertown Arsenal at Watertown, Massachusetts.
