Manuel Eissler, mining engineer, metallurgist and expert on explosives, published his first book, The modern high explosives, in New York in 1884. Many later editions followed over the next 30 years. By 1890 he was on the Witwatersrand and in November that year was appointed as a member of a four-man commission of inquiry, appointed by the government of the South African Republic (Transvaal), to investigate complaints by the mining industry that the granting of a monopoly concession to Eduard Lippert to manufacture and sell dynamite had led to poor quality explosives and high prices. The commission found both quality and price to be acceptable, but complaints continued.
Eissler produced a further book on explosives, A handbook of modern explosives (2nd ed., London, 1897), which was a practical treatise on the manufacture of dynamite, gun-cotton, nitroglycerine, and other such products. However, his main field of expertise appears to have been metallurgy. His book on The metallurgy of gold was published in 1888 and in several later editions. He also wrote The metallurgy of silver (1889), The metallurgy of argentiferous lead (1891), and The hydrometallurgy of copper (1902). Meanwhile he had been giving attention to the extraction of gold from refractory ores and in 1895 published The cyanide process for the extraction of gold and its practical application on the Witwatersrand gold fields in South Africa (London, 1895, with subsequent editions in 1898 and 1902). He also contributed an extensive paper on the same topic to the Transactions of the Institution of Mining and Metallurgy (1894/5, Vol. 3, pp. 41-105). By 1899 he was an associate of the Chemical, Metallurgical and Mining Society of South Africa, and was still listed as such in 1903.