To this experiment it may be added, that wood, which has been impregnated with water, wherein vitriol has been dissolved, is very fit for resisting putrefaction, especially if afterwards it is brushed over with tar, or some kind of paint; in order to this, the wood must be rubbed with very warm vitriol water, and afterwards left to dry, before it is painted or tarred. Wood prepared in this manner will for a long time resist the injuries of the air, and be preserved in cellars and other low moist places. It is to be observed, that if a solution of vitriol is poured on such parts of timber where a sort of champignons are formed by moisture, and rubbed off, none will ever grow there again. By boiling, for some hours, the spokes of wheels in vitriol water, they are not subject to rottenness in the parts where they enter the stocks. After boiling them in this manner, they are dried as perfectly as possible, and then, in the accustomed way, painted with oil color. 1149. _Cheap and excellent Composition for preserving Weather Boarding, Paling, and all other Works liable to be injured by the Weather._--Well burnt lime will soon become slaked by exposure in the open air, or even if confined in a situation not remarkably dry, so as to crumble of itself into powder. This is called air-slaked lime, in contradistinction to that which is slaked in the usual way, by being mixed with water. For the purpose of making the present composition to preserve all sorts of wood-work exposed to the vicissitudes of the weather, take three parts of this air-slaked lime, two of wood-ashes, and one of fine sand; pass them through a fine sieve, and add as much linseed-oil to the composition as will bring it to a proper consistence for working with a painter's brush. As particular care must be taken to mix it perfectly, it should be ground on a stone slab with a proper muller, in the same manner as painters grind their white-lead, &c.; but where these conveniences are not at hand, the ingredients may be mixed in a large pan, and well beat up with a wooden spatula. Two coats of this composition being necessary, the first may be rather thin; but the second should be as thick as it can conveniently be worked. This most excellent composition for preserving wood, when exposed to the injuries of the weather, is highly preferable to the customary method of laying on tar and ochre.