Poulsen immensely improved this process by placing the arc in an atmosphere of hydrogen, coal-gas or some other nonoxidizing gas, and at the same time arranging it in a strong magnetic field.'
The electric arc is formed between cooled copper (positive) and carbon (negative) electrodes in an atmosphere of hydrogen or coal-gas.
Petroleum products are also largely utilized in gas manufacture for, (1) the production of " air-gas," (2) the manufacture of oil-gas, and (3) the enrichment of coal-gas.
Crismer, and others, all conclusively show that acetylene is much less toxic than carbon monoxide, and indeed than coal gas.
His first research, carried out in Liebig's laboratory at Giessen, was on coal-tar, and his investigation of the organic bases in coal-gas naphtha established the nature of aniline.