Late in summer and early in autumn, the bark does not peel as it does early in the summer, when it often starts from the tree which is injured by going into trees and stepping on limbs with hard shoes. The sap will ooze out of some trees early in summer, which not only injures them generally, but it often causes the wounded part to decay. But in late pruning, the wood, when the branch is cut off, becomes sound and well seasoned; and though it may not heal over so readily as when cut early in summer or spring, it remains in a healthy state. 1137. _To preserve Wood in Damp Situations._--Two coats of the following preparation are to be applied, after which the wood is subject to no deterioration whatever from humidity. Twelve pounds of resin are to be beaten in a mortar, to which three pounds of sulphur and twelve pints of whale oil are to be added. This mixture is to be melted over the fire, and stirred during the operation. Ochre, reduced to an impalpable powder, by triturating it with oil, may then be combined in the proportion necessary to give either a lighter or a darker color to the material. The first coat should be put on lightly, having been previously heated; the second may be applied in two or three days, and a third after an equal interval, if from the peculiar dampness of the situation it should be judged expedient. _Remark._--It is highly probable (though the experiment has not been tried) that this composition would be improved by adding a small portion of the liquid leather, which is now commonly sold in London, being the refuse of the purification of fish oil by tar. Where the work will bear the expense, and is not exposed to a heat of more than 130 degrees of Fahrenheit, the best composition is the following: Equal parts of turpentine (the fluid resin, not the essential oil), bees'-wax, black resin and maltha, or coal tar, boiled together till they cease to rise--that is, till the white cream or scum proceeding from the separation of the essential oil disappears. Apply it warm with a turpentine brush--two or three coats, to cover the cracks or pores left by the brush. This lute was first proposed by Chaptal, without the addition of the coal tar, which is a great improvement. A piece of wood covered with three coats of it, and immersed for two years in water, was found to be quite dry on cutting off the lute. Take care not to allow water to fall into the pan, as it would make the hot materials explode. If the composition catch fire, put on the cover directly, and remove the pan for an instant from the fire. 1138. _Cause and Prevention of the Dry Rot._--The cause of the dry rot in wood is moisture; and to prevent well-dried timber from decaying above or under ground, is done by charring it well.