Died: 17 August 1944

Thomas Lumsden's father was William Lumsden (born in Penicuik in 1858) who was a wood turner. His mother was Mary Scott Arnott (born in Glasgow in 1857). He had two older siblings Janet (1889-1935) and Andrew (born 1898).

Thomas Lumsden attended Public Schools from 1901 to 1906, then George Heriot's, Edinburgh, from 1906 to 1912. He passed the Leaving Certificate and Edinburgh University Preliminary Examinations in Latin at Lower level and English at Higher level in April 1911, then Mathematics at Higher level in April 1912, passing Dynamics, and Science (also at Higher level) in September of that year. After having passed the Preliminary Examination for Edinburgh University, he first matriculated in October 1912.

During his first session at university, Lumsden studied Mathematics, Natural Philosophy , and Chemistry. He then took Political Economy before beginning Honours courses in Mathematics and Natural Philosophy in session 1914-15. He was ranked second top student and awared a First Class Certificate in the Advanced Honours Class in Mathematics in June 1915. At this point World War I was taking place and Lumsden had to take a break in his studies to undertake war service. He returned to Edinburgh University to take a course in Honours Natural Philosophy in 1918-19. He graduated with an M.A. with First Class Honours in Mathematics and Natural Philosophy in July 1919.

After graduating Lumsden was appointed as an Assistant in Natural Philosophy at the University of Edinburgh (under the Nichol Foundation) for session 1919-20. Robert T Dunbar was a fellow assistant in Natural Philosophy during this year. Lumsden then went to the University of Birmingham where he was appointed as a Lecturer in Mathematics in the following year.

Thomas Arnot Lumsden married Florence Milne Falconer in Abernyte, Perthshire on 4 August 1924.

Lumsden served his country during World War II and was killed in action. The following notice of his death appeared in the newspapers:-

1. Biographical Index of Staff and Alumni (University of Edinburgh).
2. Graduates in Arts, 1884-1925 (University of Edinburgh).
3. Graduates in Arts (University of Edinburgh).