At page 128 we alluded to an improvement made by Mr. Hancock, in the furnaces of boilers, which was patented by him on the 15th January, 1834 ; the object of which is to remedy the_inconvenience experienced by forma tion and adhesion of clinkers upon the fire-bars, by which the combustion of the fuel is checked, and, consequently, the production of the steam, as well as the velocity of the carriage, considerably lessened. By the present contrivance, Mr. Hancock draws out the foul floor of bare, and replaces them by a clean set, which operation, he states, is performed in much less time than is required to imperfectly clear by the rake. In the figure on the preceding page, F repre sents the space occupied for the fire-place, in a vertical plane, and A is the ash-pit. a is a floor of bars, in one casting, and in their position for use ; the outer bars on each side are cast with teeth underneath, forming racks; and there is a fixed rail under each rack, one of which is peen at b : these sup port the racks, and, consequently, the whole floor of bars, which are removed by turning the spindle of the pinion c, of which there are two, one at each end of the spiddle, so as to operate upon both sides of the grating at When a floor of bars has become foul, a clean floor is attached to it, as partly shown by the hooked joint at 9, by which, as the foul floor is drawn out, the clean one is drawn in.
A patent for improvements in boilers for locomotive engines was obtained by Mr. James Fraser, on the 7th May, 1833, upon the basis of which it is said he constructed a steam carriage, but of the completion or per formance of which we are at present uninformed. Annexed is a transverse section of the boiler ; the fire-place is at a, and the smoke, &c. is conveyed through an eccentrically-curved tube b b, imparting its heat to the sur rounding water, in its progress to the chimney. There are cross pipes, which pass quite through the flue-tube at various places, as shown by the dotted lines, that the circulation of the water or passage of the steam may not be impeded. The patentee has included in his patent some other modifications of his plans, wherein a great number of small flue-tubes are used to distribute the heat throughout the water, and to serve as supports to the fire-place and flues.
A very ingenious proposition for making use of the power of a horse, moving at his slow working pace, to communicate a high velocity to carriages upon a railway, through the medium of a new arrangement of pulleys and ropes, was invented by Mr. Joseph Saxton, of London, for which he obtained a patent, on the 20th June, 1833. The invention consists in the application of pulleys of different diameters, termed " differential pulleys ; " the principle of the action. of which will be comprehended by the following illustration : Fig. 1 (in the following page) represents a combination of two pulleys, their diameters being as 6 to 7; a being the larger pulley, and b the smaller one; c d is an endless rope, passing over the sheaves e e; the part c of the endless rope first takes a turn round the larger pulley a, and the part d also takes a turn round the smaller pulley b. If then the rope d be moved in the direction if the upper arrow, it will draw the lower part of the pulley b in the same direction ; meanwhile, the part c of the endless rope will be moving in the direction of the lower arrow, and will move the lower part of the puttey a in the same direction with this part of the rope ; consequently, the two pulley s a b (which are fixed together) would turn on the mean point f, as a fulcrum ; g is the centre of the two pulleys. Let it then be supposed, that the part d
of the endless rope be moved from h to i, it will be evident that the centre g of the differential pulleys a b would be moved to the point j, and, quently, if any object were connected to the centre of those differential pulleys, it would be propelled from g to by the endless rope e d being moved the much smaller distance of h to s, indicated by the dotted lines; and these distances will be as 13 to 1.
14.2 represents the contrivance applied to an ordinary carriage, having four wheels, as usual, two of which, k k, are shown. a and b are the differential pulleys, placed on an axis g (see Jig. 3); m is a frame which carries the differential pulleys, and turns in bearings a n, affixed to the carriage. The pro jetting ann m is forked at the outer end, as shown in Pigs. 2 and 3, at a a; and the tbrked ends serve as bearings to the axle g of the difibrential pulleys, the pulley a being permanently fixed to the axle y, whilst the pulley b is capable of turning loosely on this axis, when it is not retained by the pin g, which locks the two pulleys a and b together at the times required. By disconnecting these pulleys, the power will no longer tend to drive the carriage. R (Pig. 2) is a lever, turning on a fulcrum S : the upper end of this lever is formed into a handle, and placed under the control of a person sitting in front of the carriage ; the other end of this lever receives the flinch of a sliding socket 1 within it, as shown in Fog. 2; st is a bent lever, having its fulcrum at v, on the forked frame o, as shown in . 3. One end of this cranked lever et has a crotch, whichreceives the Ranch 1 of the sliding socket; and the other end of the lever u has also a crotch to slide the socket w, on the axis g, backwards and forwards hi an arm, fixed to the sliding-socket sr, and carrying the pin q, by which the wheels b are fastened together: a spiral spring is placed on the pin q, to force it in, when a part of the pulley which is cut away, comes opposite to the bolt; there is also a spring to prevent a sudden concussion. In lig. 2, c d is an endless rope, the part c taking a turn round the pulley a, and the part d taking a turn round the pulley b, as described in Fig. 1. This endless rope is sup porte4 at intervals of the road, on sheaves, and peones round a rigger at each to which is attached an apparatus for preserving it sufficiently tight. Now suppose the ping to be passed through the two pulleys a b, to retain them together, end the endless rope d be moved in the direction of the arrow, a similar action will take place to that described in IVA ; that is, the carriage (being attached to the centre g of the differential puller a and b) will be pro. pe1ed forward on a railway with a much greater velocity than the rope travels; and the distance so travelled by the carriage, in compariaon through which the rope moves, will depend on the difference; of the diameters of the pulleys a b; and the nearer the respective diameters of the pulleys approach each other, the greater will be the relative velocity the carriage will travel, to the velocity with which the rope moves. In order to prevent the two parts of the rope rubbing against each other, in leading on, and of the differential pulleys, the axis g of these pulleys is placed at an angle a little varying from a right angle, with the direction of the motion of the carriage.