... that of the manufacture of phenyl arsinic acid, was carried out at Ludwigshafen in one of the existing azo dye sheds without any alteration of plant, just as a new azo dye might have been produced in the same shed. It is believed that another dye factory also produced this substance. At Ludwigshafen the conversion to diphenyl arsinic acid occurred. This was again carried out in the azo colour shed, ... — by Victor LeFebure • J. Walker McSpadden