Norman Robert Pogson and observations of the total solar eclipse of 1868 from Masuliptam, India

Norman Pogson's observations of the 1868 total solar eclipse were significant in many respects. He not only distinguished the helium emission line from the Fraunhofer sodium D line, but also discovered the FeXIV green line. Until recently, he was never properly credited with these discoveries by historians of astronomy. In this paper, we discuss in detail the observations made by Pogson and his small team at Masulipatam, after describing the background of their preparation for the expedition. We also describe how they were helped by some and sidelined by others, and how various factors led to the discoveries that they being hidden from colleagues. It was only with the publication of Nath's book The Story of Helium and the Birth of Astrophysics in 2013 that Pogson's achievements in 1868 became widely known and were able to take their rightful place in the annals of science.