_Browns_ and _Fawns_ owe, in all probability, their colour to the _iron_ which their dyes contain. Iron is so universally diffused throughout nature, that it, very likely, enters into the composition of many other colours; it exists in blood, in water, and in innumerable vegetable and animal substances, as well as in earths and many minerals. Hence we ought not to be surprised that _blue_, _red_, and _fawn_ produce _olives_ from the darkest to the lightest; as well as _slate_ and _lavender_ when the shade is very light. _Fawn_ and _yellow_ produce the _feuille-morte_ or _dead-leaf_. _Fawn_ and _red_ produce _cinnamon_, _tobacco_, _chestnut_, _&c._ _Fawn_ and _black_ produce _coffee_, _maroon_, _&c._ _Blue_, _yellow_, and _black_ produce all the _dark greens_, even to black. _Blue_, _fawn_, and _black_ produce _dark olives_ and _greenish greys_. _Red_, _yellow_, and _fawn_ produce _orange_, _gold colour_, _withered-leaf_, _carnation_, _burnt cinnamon_ and _tobacco_ colours of all kinds. _Yellows_, _fawn_, and _black_ produce _hair colour_, _nut-brown_, _&c._ This enumeration is meant only to give a general idea of the ingredients proper for the production of shades composed of several colours. Where red forms a component part of the colour wanted, the goods must have a preparation of alum and argol, strong or weak, according to the fulness or weakness of the red which forms a part of the compound dye, such as the half or quarter of the quantity which is required for a full colour of red; the same as to yellow, and, in proportion, when red and yellow are joined. _On the_ YELLOW _of the Quercitron or American bark._ The quercitron bark is said to yield from eight to ten times more colour than weld, and about four times more than old fustic; this was, however, Dr. Bancroft's account, who had a strong interest in this dyeing drug, as stated in the first chapter. He also asserts, that one pound of bark with muriate of tin, will dye forty pounds of woollen a bright golden yellow, which afterwards becomes a beautiful and durable scarlet, with a fourth part less cochineal than is usually employed on other occasions for such a colour. But Bancroft did not succeed in doing away the old method of saving tartar and cochineal. His fullest _yellow_ upon cloth, the author has, however, often tried and found it rich and golden; the process is as follows: Cloth one hundred pounds; bark in powder, and in a bag, ten pounds; muriate of tin, or _murio-sulphate of tin_, (_for which see forward_,) ten pounds. The bark in the bag must be first immersed in the proper sized vessel for six or eight minutes; then add the solution of tin and stir it well for two or three minutes, when the cloth must be put in, and kept in motion by two or three men working over the winch from end to end; then proceed to boil; and, in _fifteen minutes_ boiling, the highest yellow is produced; a longer time would turn the yellow brown.