In the late 1870s, he worked in the
Cavendish Laboratory at Cambridge under
James Clerk Maxwell. In 1880, he became the first professor of physics at the
University of Birmingham. He was the developer and
eponym of the
Poynting vector, which describes the direction and magnitude of
electromagnetic energy flow and is used in the
Poynting theorem, a statement about energy conservation for
electric and
magnetic fields. This work was first published in 1884. He performed a measurement of
Newton's gravitational constant by innovative means during 1893. In 1903 he was the first to realise that the
Sun's radiation can draw in small particles towards it: Poynting wrote most of it. He was awarded an
honorary MSc in Pure Science in 1901 by
Birmingham University. Poynting lived at 11 St Augustine's Road,
Edgbaston with his family and servants for some years. He previously lived at 66 Beaufort Road,
Edgbaston (demolished) and died of a diabetic coma, aged 61, at 10 Ampton Road, Edgbaston in 1914. In 1880, he married Maria Adney Cropper. He was survived by his widow, a son, and two daughters. ==Legacy==