In 1799, Malthus made a European tour with William Otter, a close college friend, travelling part of the way with Edward Daniel Clarke and John Marten Cripps, visiting Germany, Scandinavia and Russia. Malthus used the tour to gather population data. Otter later wrote a Memoir of Malthus for the second (1836) edition of his Principles of Political Economy.[40][41] During the Peace of Amiens of 1802 he travelled to France and Switzerland, in a party that included his relation and future wife Harriet.[42]
In 1803, he became rector of Walesby, Lincolnshire.[25]
In 1805, Malthus became Professor of History and Political Economy at the East India Company College in Hertfordshire.[43] His students affectionately referred to him as "Pop", "Population", or "web-toe" Malthus.
Near the end of 1817, the proposed appointment of Graves Champney Haughton to the college was made a pretext by Randle Jackson and Joseph Hume to launch an attempt to close it down. Malthus wrote a pamphlet defending the college, which was reprieved by the East India Company within the same year, 1817.[44]
In 1818, Malthus became a Fellow of the Royal Society.
