The motion thus caused in this part of the machinery, operating upon its duplicate parts on the other side, of course produces by its

action, a corresponding movement; and the slider in the trough v, moved by the action of the mercurial tube p, being removed from its position, allows the water to fall into the other pipe w, and as it ascends, suffers the float y to descend, and rising into the main cylinder, thus lifts again the beam at b, and its connexions, and forces down the cap e on the top of the other cylinder.

After the vacuum is effected in the cylinders, the air must be admitted, to allow the water to be discharged, and the caps to be raised: this is accomplished by means of a sliding valve in the air pipe mm, acted upon by chains tt, attached to the floats in the reservoir, and as motion is given to them, the valve is made to slide backwards and forwards, so as to allow of the free admission of atmospheric air.

Chains uu, with suspended weights, open the cocks in the pipe kk, and produce the alternate flow of the gas, and regulate and modify its supply.

In the pipes gig and hjh are clacks, or valves, to prevent the return of the water, when the air is admitted into the cylinders.

Mr. Brown claims to be the inventor of the combination above described for effecting a vacuum, however much it may be varied by the mechanical means with which it may be used; and also, the inventor of applying a vacuum produced by the combustion of inflammable gas, to raising water, and to the production of motion in machinery by the pressure of the atmosphere.

Specification of a patent granted to Thomas Howard, for an engine to be set in motion by the vapour of alcohol, ether, or other volatile liquids.

I ERECT two metal cylinders (A B, drawing No. 1,) made firm and secure by any of the ordinary methods. These cylinders communicate with each other at the lower part, by a horizontal tube, or sinaller cylinder, or otherwise, so as to form a free passage at C, from one to the other. Then such a quantity of fixed oil, mercury, or other fluid, or substance becoming fluid, but not evaporating at the degree of heat to which it will be there exposed, is introduced into these cylinders, as will fill the base of the one, the intermediate passage, and nearly the whole of the other cylinder, to serve as a medium of heat necessary for generating the vapour for working the engine. Within one cylinder B, is placed a piston, exposed above to the pressure of the atmosphere, and having a rod and stuffing, in the usual manner. In the other cylinder A, is placed a thin metallic dish, floating freely upon the oil, or other fluid before mentioned. This latter cylinder has a top fastened down quite air-tight, through the centre of which top, is brought a tube E, proceeding from the condenser (hereinafter described,) the lower end of which tube within the cylinder, terminates in a nosle pierced with many small holes. This tube is passed through a piece of cork, wood, or other imperfect conductor of heat, fixed into the top of the cylinder with a ring

screwed down above it, in which the tube is made secure by a small screw F, in order that all these parts may be air-tight. In the top of the cylinder A, is an oblong orifice, closed by a valve G, of the like

form, which opens inwards by a rod H, striking the valve near one end with the advantage of a lever (as a door,) at which end is a small hollow, for the purpose of receiving the rod; at the other end, the valve is confined to its seat by a crane-neck spring, bending over, above it (as in the drawing No. 1, near G:) the rod is entirely detached from the valve, so that the rod has the power only to open the valve; the advantage of which is, that any accidental irregularity in the motion of the rod, will not derange the valve itself. The valverod passes through an air-tight stuffing box I, in the usual manner. A safety valve K is placed on the top of the cylinder A. There is an orifice through the piston, into which is fitted a plug, or stopper; by means of which the height of the oil, or other fluid, hereinbefore described, above the piston (which should always be kept a little above the piston,) may be regulated when necessary. The oil, or other fluid, may at any time when required, be withdrawn from the cylinders by a cock, N, near the bottom, and may be again introduced by the top of the piston cylinder through the orifice in the piston. The degree of heat necessary for the purpose of working my Vapour Engine, is obtained by means of a sufficient number of lamps, 0, 0, 0, 0, on the principle of the Argand lamp, and on a large scale, when required. These lamps are supplied with oil, or other inflammable liquid, or gas, and placed below the cylinders, and the chimnies of which lamps are passed into, and through, a thin metallic or other covering, which covering is carried round both the cylinders (except the upper part of the piston cylinder,) at a small distance from the cylinders, so as to confine and carry the heated air entirely round them. The lamp chimnies should be made of metal, with a hole therein, covered with talc, through which the flame may be seen, for the purpose of regulation. There is a tube or chimney, P, at the top of the last mentioned covering, which tube may be more or less closed by a top or register, Q, the better to regulate the heat of the air within the covering. By means of a small forcing pump, R, which is set in motion, and the length of its stroke regulated by any of the ordinary methods in use, in the steam engine, the tube E, which enters the top of the vapour cylinder, is supplied from the condenser with the liquid, which is afterwards to be converted into vapour, within the cylinder A. The liquid to be employed may be either alcohol, ether, essential oil, or other liquid which evaporates more rapidly, and at a lower temperature than water. I do not, however, confine myself to any particular liquid or liquids, for even water may be used if the heat be sufficiently raised. The degree of heat to which it is proper to raise the oil, or other fluid medium within the cylinders, must be varied according to the nature of the liquid to be evaporated, and to the extent of power required. In order readily to ascertain, and be enabled to regulate correctly the degree of heat within the cylinder, a thermometer is attached to any convenient part, with its bulb passed through the cylinder into the oil or other fluid medium. From the nosle of the tube E, above described, a sufficient quantity of the liquid before mentioned is thrown by the action of the forcing pump, R, not gradually, but quickly,

and at once, upon the dish, which being previously heated by the oil (or other fluid medium,) on which it floats, quickly converts the liquid thrown on it into vapour, which vapour receives an increase of expansive power by the heat of the cylinder, and pressing upon the oil (or other fluid medium,) and dish floating thereon, forces the oil through the horizontal passage C, into the piston cylinder, and raises the piston to its highest point of elevation. The valve G in the vapour cylinder being now opened, the vapour escapes by a tube S, into a separate vessel Z, (as in the steam engine of Watt,) and is there condensed; the piston then returns by the pressure of the atmosphere, and the dish is carried again to the top of the vapour cylinder. The valve G is now closed, and a fresh portion of liquid is thrown by the forcing pump upon the dish, to be converted into vapour, and the operation is repeated as before. The dish is not absolutely necessary, as the liquid may be thrown upon the oil (or other fluid medium;) but I prefer a dish, which should be made of copper, with a flat bottom, the internal surface of which should not be polished. A sliding valve o, is placed across the horizontal tube, or passage, between the two cylinders, so as, occasionally, either entirely or partially, to close the passage from one cylinder to the other, by means of which the motion of the engine may be easily regulated or stopped. In the top of the cylinder A, is fixed a tube S, by which the vapour is conveyed from the cylinder to be condensed; and this tube should be divided, and a ring of cork, wood, or other imperfect conductor of heat a, should be placed between the two parts, which should then be screwed up together, air-tight. By means of this arrangement, the transmission of the heat from the cylinder to the condenser is interrupted. The other end of the tube is inserted into, or communicates with, a circular tube or hollow ring, V V, into which a number of smaller tubes, marked severally U, made of copper or other metal, as thin as the required strength will permit, are fixed and arranged in a circle. These smaller tubes are also inserted into another vessel below, W, which forms a reservoir for the vapour when condensed. The liquid formed by the condensed vapour may, by means of a pipe with a cock d placed in the bottom of the vessel, be withdrawn when required. The outer and upper part of the condenser has upon it a circular basin or open vessel X, into which water is thrown by a pump or otherwise, as may be convenient. The smaller tubes severally marked U, are each wrapped round and covered on their external surface with flannel, or other porous substance of the like nature, which is carried over into the upper ring or basin X, from whence, being previously wetted, the water is absorbed, and the flannel or other porous substance used, acting like a syphon, conducts it down the outside of these tubes into a vessel Y below them, from which it may be allowed to run off, or be pumped again into the upper vessel X, if required. Within the hollow circle formed by these smaller tubes, severally marked U, is a machine upon the principle of a fan, kept in rapid motion by the engine or otherwise. By this means a continued stream of air is thrown upon the wet flannel, or other porous substance, and the heat is conseVOL. V.-No. 1.-JANUARY, 1828.-4