The annoyance attending this process by the evolution of the immense quantities of smoke from the ignited matter, besides the entire waste of the volatile products, induced the late Earl Dundonald, many years since, to introduce a plan for preventing the former, and saving the latter. One of these tar works, as they were called, was erected at Mr. Wilkinson's great works at Bradley, another at Tipton, and a third at the Level Colliery and iron works upon Dudley-wood. Being erected in the vicinity of large iron and coal works, the iron masters furnished the tar works with raw coal, and received in return the cokes produced by such coal, the proprietors being compensated by the volatile products, viz. tar, pitch, varnish, and ammonia.