This varnish is prepared by taking of good linseed oil 1 gallon, and of umber half a pound, and boiling them together until the oil becomes very brown and thick, when they are strained through a cloth and boiled again until the composition is about the consistency of pitch, when it is fit for use. Having prepared this varnish, clean well the copper or iron plate or vessel that is to be varnished (japanned), and then lay vermilion, mixed with shellac varnish, or with drying oil, diluted with turpentine, very thinly on the places intended to imitate the clean parts of the tortoise shell. When the vermilion is dry brush over the whole with the above umber varnish diluted to a due consistency with turpentine, and when it is set and firm, it must be put into a stove and undergo a strong heat for a long time, even two weeks will not hurt it. This is the ground for these beautiful snuff boxes and tea boards which are so much admired, and these grounds can be decorated with all kinds of paintings that fancy may suggest, and the work is all the better to be finished in an annealing oven.