Rust, denotes the calces, or vulgarly the flowers of metals, which are generally produced by exposure to moist air, or in damp situations ; though the former may also be obtained artificially, by corroding or dissolving metals, in a proper Menstruum (which see) ; and in which case it is termed a magistery.

Having already pointed out (vol. iii. p. 30), a few general methods of preserving iron from rust, we shall, at present, only add a receipt by which the latter may be removed. It consists in combining a certain proportion of quick-lime with mutton fat, into balls, which must be rubbed on the utensil, till it has entirely obhiterated the rust: after this coating has remained for a few days on the metal, it is removed with coarse flannel or other rags j when another composition, made of equal parts of charcoal, red calx of vitriol, and drying oil, is applied by continued friction, till the surface be restored to its pristine brightness.

Rust. - In addition to the hints given in the articles Iron, Steel, and likewise p. 434 of this Supple-ment, tor preserving those metals from the injurious effects of rust, we think it usetul to add the following: As experience proves, that the application of common oil, as well as that of paint, is but an imperfect security against the corrosive effects of air and moisture, we are informed, that articles manufactured of iron are not liable to be attacked by the rust, if this metal be previously poured into melted lead; then suffered gradually to cool; and this simple process be repeated several times.

Another mode of coating Iron, with a view to prevent the formation of rust, is said to be obtained by the application of spermaceti, while the metal is hot : thus, a kind of bronze will be the result. - A more permanent varnish, however, is that of rubbing iron in a state nearly red-hot, with the horny hoofs of cattle, which are previously dipped in a small portion of oil-: this process is asserted to afford the best defence from the destructive influence of air and humidity.