BOLT, _v._ To spring out with speed and suddenness. To gib, or diverge from the course. BOLUS, _s._ A medicine made up into a soft mass larger than pills. BONE, _s._ The solid parts of the body of an animal. The bones of birds are nearly all hollow, and communicating with the lungs, are thence filled with air, so as to render them more buoyant for flight. The breast bone (_sternum_) extends much lower than in quadrupeds, and is distinguished by a ridge like the keel of a ship, except in the ostrich, &c., which do not fly. The bones of the wings are similar to the fore-legs of quadrupeds.—_Rennie._ BOOM, _v._ To rush with violence. To make a noise like a bittern. BOONK (_Ardea minuta_, LINN.), _s._ This is a very rare bird, and few instances only are recorded of its being killed in England. A male was shot near Bath, in the autumn of 1789, perched on the stump of a tree on the bank of the Avon. In the month of May, 1808, a female was shot contiguous to the river Creed, and Dr. Fleming tells us that one was shot at Sunda, Orkney, in 1805. It is more frequent in some parts of the European continent, particularly in Switzerland, and, as Temminck informs us, in Holland.—_Montagu._ BOOT, _s._ A covering for the leg. All boots for going in the wet, answer much better if kept at least half a year before they are worn; and they should afterwards never be suffered to get too hard. Water boots should be invariably worn over an extra pair of coarse yarn stockings, without which you do not give them a fair trial. So far from being hard to the feet, they are the softest possible wear, and may be made very light. They should always be made to draw, when required, very far above the knees, in order to protect them from cold or wet. Various dressings are recommended, though, perhaps, almost any grease may answer; but the first and most effectual application might be tar, tallow, and bees’ wax, melted, (not too warm) and then poured into the boots; which, after having this shaken into every part of them, should be hung up to let it run out. By this dressing, and the sacrifice of the first pair of stockings that follows it, we may walk in the river with more comfort than a Bond-street lounger would cross the street after a shower. This recipe, however, though a double defence, I do not mean to say is absolutely necessary. As another good recipe, I should prefer the following one:— RECIPE. Drying oil 1 pint Yellow wax 2 ounces. Turpentine 2 ounces. Burgundy pitch 1 ounce. Melt those over a slow fire, and then add a few drachms of essential oil of lavender (or thyme). With this your boots are to be rubbed with a brush, either in the sun, or at some distance from the fire. The application must be repeated as often as the boots become dry again, until they are fully saturated.