The liquid is filtered and the lead salts separated by means of a current of hydrogen sulphide.
"The Medicinal Plants of the Philippines"
T. H. Pardo de Tavera
The combination of two volumes of H with one volume of S is found to produce two volumes of hydrogen sulphide.
"An Introduction to Chemical Science"
R.P. Williams
12, 1888 474,591 Extracting Gold from sulphide Ores .
"Edison, His Life and Inventions"
Frank Lewis Dyer and Thomas Commerford Martin