From a machine of this kind we may expect all that can be clone by a simple ladder ; but by the addition of a rope, pulley, and basket, it may be made capable of lowering goods, or helpless and infirm persons, and children. The pulley should be suspended from a round, at about three feet from the upper end, which round must in that case be made of iron. The rope should be rather more than twice as long as the ladder, and of a sufficient strength to bear four hundred weight. The basket should be very shallow, and surrounded by a strong sack-cloth, so as to be rather a sack with a basket bottom, and a hoop in the mouth to keep it extended ; this will fold, and lie close to the under side of the ladder, where it should always be lashed by the spare end of tl-c rope, the remainder being extended be tween the pulley and the lower end of the ladder, so as to be in no danger of entanglement. In this way, the opera tion of the ladder will not be at all impeded, and the rope will always be ready for action, by untying the end of the rope, and thus releasing the basket. This rope will be extremely useful to haul up the leathern pipe or hose of an engine ; and the fire-man ascending the ladder, will be able to direct the jet to the greatest effect into the win dows of the first, second, or third floor, the rope sustain ing the weight of the pipe, which would otherwise be too great for one man to hold when upon the ladder.
A machine is described in the Annual Register, some years ago, with a rope and hasket ; but a pole from 36 to 46 feet in length was used in place of the ladder. This pole had the pulley fitted into a mortise, at three feet from the upper end ; it had also at each end an iron cross bar fixed, to project perpendicularly on each side, one to bear against the wall, and the other upon the ground, and form a foot to keep the pole steady. To assist in raising the pole, two smaller poles or handles were connected with the great one, at two or three feet above its middle, by eyes which admitted a motion in every direction. Several persons could apply their force very advantageously at the ends of these poles, to elevate the great one ; and when it was raised, the poles formed legs like a tripod, to strength en the great pole, and prevent it from bending in the mid dle. It is stated that a pole of this sort was elevated, and two or three persons lowered from the upper windows of a house, into the street, in the space of 35 seconds, or rather more than half a minute. Still, as the pole was five inches diameter at the base, and three at the upper end, it could not, with the addition of the side poles and basket, be rendered very portable, and, from its length, it would be troublesome to turn the angles of narrow streets, and therefore we prefer the ladder with wheels, which is ex tremely easy of transportation, and which, from the facility of raising it by the balance weight, can be elevated to turn a narrow corner. If it is trussed, as we have described, it will have as much strength as the pole, when propped In the middle by the two short ones.
We think it is scarcely necessary to describe any other machines, except very briefly. The principle of several of them is to have two, three, or four ladders, fitted one upon the other, or rather one within the other, and provid ed with a tackle by which they can be elevated to the height of the window. The most complete of this kind is described by the Society of Arts, in their Transactions, vol. xxviii. The base of the machine is a four wheeled carriage, with a pair of shafts for a horse to draw it. The
lowest of the three ladders is fitted in the carriage by a bolt, on which it can be inclined sidewise at pleasure, to reach the window, and retained at any elevation by a frame with screws. The three ladders are made to fit one within another, and provided with iron clamps to confine them together. In the back of the frame, beneath the ladder, is a windlass, which receives the ropes for sliding up the ladders. These consist of two parallel ropes, proceeding from the windlass, and passing over two pullies, fixed at the upper end of the principal or lowest ladder, and the ends are made fast to the bottom of the second ladder. Therefore, by turning the windlass, the ropes are drawn, and the second ladder is elevated upon the first. The third ladder is likewise provided with two parallel ropes, passing over punks, at the top of the second ladder, and attached to the bottom of the third; but the opposite ends of these ropes, instead of being carried down to the wind lass, are made fast to any part of the lower ladder : in this way they have the same effect to raise up the third upon the second, when that is elevated upon the first by means of the windlass. The remainder of the apparatus is a windlass, in front of the machine, with two ropes passing over pullies at the top of the highest ladder, and suspend ing a box or chest, in which the goods are to be lowered down. The upper end of the ladder is provided with a bent iron bar, to lean against the window, and thus retain the top of the ladder at such a distance from the wall, as to admit the box to ascend and descend clear of it.
We have seen another machine on a different principle : its carriage supported an upright post, which was fitted to turn round in the manner of an axis. The top of it formed the fulcrum of a very long lever, which, at one end sup ported the basket, and at the other a considerable balance weight. The height of the vertical pillar was such as to raise up the centre of the lever to about half the height from which the descent was intended to be made. The lever then required to be sufficiently long to reach to the window, when elevated at an angle, and also to the ground when its end was depressed. The lever had an arch or toothed sector attached to it, beneath the centre, and this was worked by a pinion with wheel-work, by which two men, turning a handle and standing upon the platform, could command the elevation of the lever, and the basket attached to it. By raising the end to the height of the window, and turning the vertical axis round, they could make the end of the lever enter the window, and the per sons having put themselves into the basket, the end was to be a little raised ; then, by turning the vertical axis the basket was brought over the street, and lowered safely down by the men at the handle. The basket could again be elevated, and another person brought down with equal ease. The only objection to this machine is, that the lever would require to be of such a great length, and hav ing no support at its 'ends, would require a cumbersome framing, to render it sufficiently strong. A simple and effective mode of trussing would be Mr Smart's plan of dividing the rod lengthwise by a saw kerf, and introduc ing blocks to swell the beam in the middle, and give it stiffness, as we have before described of the ladder. A boom and stays, to act like the shrouds of a ship, would give it great strength without any increase of weight.