Edward H. Johnson, a metallurgist in Johannesburg, was a foundation member in 1894 of the Chemical and Metallurgical Society of South Africa (from 1902 the Chemical, Metallurgical and Mining Society of South Africa). He served on its council in 1898/9, then as joint vice-president to 1906 and finally as president for 1906/7. During these years he contributed several papers on the extraction and metallurgy of gold to its Proceedings and its Journal, for example, "The reduction of zinc-gold slimes" (June 1897); "The stamp milling of gold ores in its relation to cyaniding" (December 1897); "A means of economising water in concentration" (October 1898); "The smelting and refining of zinc-gold slimes" (with W.A. Caldecott*, July 1902); "The precipitation of gold from cyanide solutions" (as co-author with Caldecott, July 1903); and 'The classification of tailing pulp prior to cyaniding" (1910/11).
In 1905 Johnson worked as metallurgist and cyanide manager at the May Consolidated Gold Mining Company in Germiston. He was an early member of the South African Association for the Advancement of Science and at its annual congress in Johannesburg in 1904 read a paper on the reduction works of Transvaal gold mines. The next year, when the association met jointly with the British Association for the Advancement of Science in South Africa, he wrote a chapter on "South African metallurgy" for the volume Science in South Africa (Flint & Gilchrist, 1905) compiled before the meeting.
In 1912 Johnson contributed to A textbook of Rand metallurgical practice, the principal author of which was R.S.G. Stokes*. He was still a member of the Chemical, Metallurgical and Mining Society of South Africa when the society celebrated its fortieth aniversary in 1934, and was still listed as a living past president in 1940.