Water being forced by the lower receptacle of the boiler, it flows through apertures in the short tuba into the lower ends of the spiral tubes, where ebul htion takes place, and the water mixed with the steam is driven upwards through the spiral sheet of tubes. The inclined position of these gives the water forced ' a tendency to flow back under the steam • that which is on decreases as it ascends, by being converted into steam : on arriving at the upper recep tacle, the steam, together with a small portion of water, enters the float cham ber, where the water falls to the bottom, and supports the float while the steam passes into the steam-pipe. When a greater quantity of water is accumulated than is evaporated in the float chamber, a rise of the float will be produced, and a proportionate decrease in the quantity of water pumped into the boiler, occasioned by the communication of the float with the steam-cock of the engine. By this arrangement it will be noticed that the float chamber is also the apa ratory," the upper portion constituting a steam reservoir, and the lower portion, which is in the centre of the fire, serves as a supplementary boiler. The steam pipe commences at the top of the float chamber, and is carried down by the side of and in contact with the inner casing, and also three or four times round the furnace chamber ; forming a protection to the casing, while the steam derives, in consequence an increase of expansive force.
The whole of the frame and engine is supported upon springs, and to allow of their application to the driving cranked axle, two strong rods are used, each of which is firmly jointed at one end to the frame, and attached at the other end to the cranked axle by bearings, by which the frame is allowed to rise and fall. The guiding operation is produced by means of a little wheel running behind (but centrally between) the two fore wheels, acted upon by a system of levers moved by the steersman. The apparatus consists of two rings of iron, of equal diameter, turned truly to each other; to the lower ring is attached by brass bearings, the axle of the guide-wheel, and a branch iron proceeds from the front of the upper ring to the axle of the two fore wheels,"where it is connected by two joints, that allow the guide wheel and its bearings to rise and fall freely, but prevents its side motion without moving the two fore wheels. By turning two handles opposite to the steersman's seat, a vertical spindle communicates the motion to cross levers below, which acting upon two rods connected thereto, and to the apposite sides of the under horizontal ring, the latter traverses under the upper ring, (which has no horizontal motion) and sets the guide-wheel to the required angle to the line of motion to make the turn in the road, in the same manner as setting the rudder to the stern of a boat. In the drawing of the carriage on the opposite page, those parts that are brought into view, considered in connexion with the foregoing description, will afford the reader a pretty correct notion of the general structure. The engines are situated in a case underneath the carriage body ; one of them is shown dotted in at a, which with its piston rod and connecting rod b gives motion to the cranked axle of the running wheels d of the carriage. To stiffen the wheel, there is a stout iron ring bolted to the
inside of the spokes, and having arms communicating with a central piece that is fixed to the nave. The boiler e is bolted to a strong iron framing, and is contained in a double case; • the angular dotted lines across it represent the inclinations from a vertical line of the spiral sheet of tubes ; and the dotted lines in the centre are intended to express (which theydo but imperfectly) the position andarrangement of the flost_and steam chamber ; f is the guiding spindle and g the steering wheel, surrounded by its two traversing rings, the upper ring being attached by a curved iron arm to the fore axletree, and the lower one to the axis of the steering wheel. Between the transit irons of the fore wheels, and the bar to which the guide-wheel is attached, there is a strong spiral spring, acted upon by a screw, to regulate the pressure, according to the state of the roads.
A patent was sealed on the 31st of August, 1830, for " certain improvements in locomotive carriages," by Mr. John Hanson, of Hudders field, in Yorkshire. The objects of the patent are twofold ; that of communicating the power of the engine from the crank axle to the four running wheels, by means of pitched chains and wheels ; and that of applying a ball and socket to the ends of the running wheel axes, inside the naves, so as to permit the wheels to roll in an inclined direction, as well asel to the sides of the carriage, in order may roll more easily over curved portions of the road.
In the first-mentioned division of the patent, we can discover nothing that is new in prin ciple, or better in detail, than what every mechanic is familiar with ; we therefore omit further notice of it in our condensed treatise. The second-mentioned claim of invention pos sesses some novelty, and is not without merit ; accordingly, we give it a place here. In the annexed cut is represented a vertical section of one of the wheels; a is the axis, terminated by a spherical ball b, into which is fixed a stout pin 4 that comes against a stop in the interior of the nave or box d, and causes the wheel to revolve with the axle. The wheel is kept at pleasure in the vertical position, by means of a frame, not shown in the drawing ; and this frame is placed under the control and management of the steersman, who site in front of the carriage, and who, by means of connected levers, inclines the frame to the right or left, and thus causes the wheels instantly to assume the same position, and make the deviating course required. It is obvious that a common axis would not effect this operation; and there is, perhaps, no better mode of attaining the object of the patentee, than the one he has adopted. The ball, it will be seen, has sufficient play by letting one side turn against a conical piece e, formed spherically on its inner edges, and bringing out a boss f from the outer plate, having at its end a concavity, which fits the sphericity of the ball; and as these opposite cavities may be made to recede or approach, by means of the screw-bolts g g, which connect them, they thus afford ready means of adjusting the surfaces, so as to make the axis work pleasantly.