Lionel William Macer, British surveyor and mining engineer, was the son of Moses Macer and his wife Susan Pigott, born Day. He came to South Africa in or before 1910, for in that year he resided in Pilgrim's Rest, Mpumalanga. In 1913 he became a member of the Geological Society of South Africa. He was associated with the Transvaal Gold Trust and was a leading member of the Mines and Claimholders Association of Pilgrim's Rest. Two articles by him were published in the Pilgrims Rest Goldfields, Mines and Claimholders Quarterly (no dates available): 'Dykes and sills' (Vol. 1, pp. 11-13), and 'The persistence of ore in depth' (Vol.1, pp. 13-16). In 1915 he applied for a United States patent (which was registered in April 1917) for new and useful improvements in rail-joints. Later he contributed a 'Note on the footwall beds of the Far East Rand' to the Journal of the Chemical, Metallurgical and Mining Society of South Africa (1917/8, Vol. 18, pp. 70-73).
On 29 January 1910 in Ilford, England, Macer married Ada Elizabeth Franklin, with whom he had two sons and a daughter. At the time of his death he resided in Histon, near Cambridge, England.