Born in Annapolis Junction, Maryland on March 15, 1873, he received his B.A. in 1893 and his Ph.D. in 1897 from Johns Hopkins University. After obtaining his degree, he remained at Johns Hopkins for a few years and then worked briefly for the U.S. Department of Agriculture. In 1903, he took a position at the National Bureau of Standards (then only two years old). Noah Dorsey died in 1959. For six decades he was involved in the life of the scientific enterprises of the NBS. Most of this time was spent on electrical measurements. From 1914 to 1922, he worked on standards of radioactivity and x-ray measurements, and in 1921 his title was Chief of the Radium Section. His 1921 book, The Physics of Radioactivity, was extremely valuable at the time as a guide for all scientists in the emerging fields of medical physics, health physics and university based studies of radioactivity. The most extraordinary section deals with his detailed description of the burns he received from working with radium and radon sources and his cautionary statements on source handling.