448px-PSM_V11_D660_William_Stanley_Jevons

Engraving of William Stanley Jevons, 1877

Engraving of William Stanley Jevons, 1877 (Popular Science Monthly, Volume 11). Author unknown. This image is in the public domain in the United States because its copyright has expired. Courtesy of Wikipedia Commons: http://en.wikipedia.org/wiki/File:PSM_V11_D660_William_Stanley_Jevons.jpg