THOMAS CORWIN MENDENHALL (1841-1924) SIGNED CARD, “Yours faithfully, T. C. Mendenhall/Florence Italy/Nov 2, 1909”, on a card 4.25 x 2.25, by the American scientist: physicist and meteorologist who was the first professor hired at Ohio State University (1873) where he taught physics and mechanics, superintendent of the U. S. Coast and Geodetic Survey, and father of author profiling. He was also the president of Rose Polytechnic Institute in Terre Haute, Indiana (1886-89). He invented the Gravimeter, which measures the strength of a gravitational field. In 1887 Mendenhall published one of the first attempts at stylometry also known as author profiling, the quantitative analysis of writing style, which was used as a technique in determining the Shakespeare authorship question. The card is boldly signed and is in fine condition, with minor age toning.