As to narrow spaces, it is evident that where the bars can go the coach can go, as they are wider than the wheels; and consequently, if they are cleared, all is safe. The swing-bar is an excellent invention, as a horse works in it from either shoulder, and therefore quite at his ease. A sharp and experienced driver may calculate exactly the space sufficient to pass between two bodies at rest, and may therefore pass with confidence and at ease. As, however, in streets, he must meet many carriages driven by inexperienced or intoxicated fellows, who do not for a moment move in any direct line, he should allow them ample room, and proceed with the utmost caution. A driver must be incessantly on the look-out, must watch every vehicle that approaches, and give it more room than it may seem to require. ASCENDING AND DESCENDING. In going up hill, it is in general best to trot up at first, and to walk afterwards. In going down hill, it is best to keep the wheelers tight in hand, to let the leaders just clear the bars, and to come gently down. In the latter case, a turn of the reins of the wheel-horses may be made round the little finger. (Plate XLIV. fig. 4.) Although, however, it may be necessary to catch up wheel-horses, and make them hold back their coach down hill, there is nothing in which a light finger is more essential to safety. The manner in which some persons haul at horses’ mouths, when descending with a load, considerably adds to the difficulty, by trying the strength of the tackle. But this is not all: these persons should be aware that all this force employed on their horses’ mouths is so much added to the pressure of the coach; in proportion to it is that pressure increased. The horses are then drawing by their heads! The objections to a locked wheel, with a top-heavy load, have already been stated. If, however, with a heavy load, and upon a smooth hard road, a wheel must be locked, it should be that next a ditch, or other dangerous part. In going down hill, a coach always strikes on the side on which the wheel is not locked. The coachman should therefore keep as much as possible on that side of the road on which the wheel is locked: by crossing the road, if he meet or have to pass any thing, the coach will not strike; and by holding that way, at any time, it will prevent overturning. The coach naturally strikes in a direct line from the perch-bolt.