In the days before adding machines and graphing calculators, Hoy D. Orton (1842-1877) was himself a lightning calculator. He gave demonstrations and lectures, dazzling all with his ability to add long columns of numbers and compute interest – simple and compounded – quickly, accurately, and in his head. The Times-Picayune proclaimed that Orton’s free lecture should be “attended by all who are interested in the mysteries and wonders of mathematics” (19 Jan. 1870).
