List of sources:
British Association for the Advancement of Science. Report of the seventy-fifth meeting... South Africa 1905, list of members.
FamilySearch: John Ray Cowell. https://www.familysearch.org/ark:/61903/1:1:QPHG-Y2KD
John Ray Cowell. In Grace's guide to British industrial history.
http://www.gracesguide.co.uk/John_Ray_Cowell
as on 2016-5-4.
Journal of the Mechanical Engineers' Association of the Witwatersrand, 1902-1903, Vol. 1.
Journal of the Transvaal Institute of Mechanical Engineers, 1905-1910, Vol. 4-8.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Cowell, John Ray.
Orr, J. Presidential address. Annual Proceedings of the Associated Scientific and Technical Societies of South Africa, 1938, pp. 15-86 (p. 21).
Shorten, J.R. The Johannesburg saga. Johannesburg: J.R. Shorten, 1970.
South African Association of Engineers and Architects. Proceedings, 1897-1898, Vol. 4.
South African who's who, 1908, 1909, 1919/1920, 1931/1932.