Thomas Young - The Last True Know-it-all

new biography, Andrew Robinson argues that Young is a good contender for the epitaph “the last man who knew everything.” Young has competition, however: The phrase, which Robinson takes for his title, also serves as the subtitle of two other recent biographies: Leonard Warren’s 1998 life of paleontologist Joseph Leidy (1823-1891) and Paula Findlen’s 2004 book on Athanasius Kircher (1602-1680), another polymath. B Young, of course, did more than write encyclopedia entries. He presented his first paper to the Royal Society of London at the age of 20 and was elected a Fellow a week after his 21st birthday. In the paper, Young explained the process of accommodation in the human eye —on how the eye focuses properly on objects at varying distances. Young hypothesized that this was achieved by changes in the shape of the lens. Young also theorized that light traveled in waves and he believed that, to account for the ability to see in color, there must be three receptors in the eye corresponding to the three “principal colors” to which the retina could respond: red, green, violet. All these hypotheses were subsequently proved to be correct. C Later in his life, when he was in his forties, Young was instrumental in cracking…