appear to us to have been indebted in a great degree, to this fine example.

In the body of the still, (that part where the vapour is generated) there is no improvement proposed, but an enlarged capacity of its globular head, to cause the watery particles to fall back into the still; this part of the apparatus we have omitted in our diagram, as it requires no additional explanation; the engraving, therefore, relates wholly to the apparatus for condensation.

a is the termination of the neck of the still which conveys the vapour into the " upper drum" b, whence it is divided among a number of small vertical tubes c, which the patentee says, should not exceed of an inch in their interior diameter. As the tub inclosing this apparatus is filled with cold water, the condensation immediately commences in the upper drum, and is completed in its subsequent progress through the vertical tubes, and the "lower drum" d. From thence the fluid runs down a central neck e, into the trapf, from the upper part of which trap it enters the cooling worm. It is evident that the trap is in working, always partly filled with liquid, and the neck e being immersed therein, any vapour which may have escaped condensation can pass no further. The trapf has a funnel-shaped bottom, from which a pipe h passes through the coils of the worm, and through the side of the tub, where it is furnished with a cock, for the purpose of drawing off any impure spirit which may be separated from the wash in the first stage of the process; and to discharge what may remain in the trap when the process is over. To the trap fis also attached another pipe i, called

the safety pipe, for the purpose of allowing" the egress and ingress of atmospheric air from and to the condenser, to prevent both pressure and a vacuum therein." The coils of the cooling worm are made octangular; the worm itself is made flat, and of considerable breadth; a transverse section of it is exhibited in the separate figure k, which shews it to be in the form of a parallellogram, whose longest sides are four inches, and its shortest half an inch wide. This octangular worm after making six complete turns, assumes a circular shape and diverges off to pass through the side of the tub; at its end outside the tub, which is made a little tapering, is fitted, and is to be occasionally applied, a crane necked pipe, which pipe may be elevated or depressed at pleasure, for the purpose of keeping three or more of the coils of the worm full of liquid. This crane necked pipe is intended to be applied in hot weather, or hot climates, to cool the spirits more effectually, and prevent their evaporation by subjecting the same in a greater degree to the effect of the cold water in the worm tub.

An additional apparatus to be used in hot climates of undoubted utility is likewise recommended by the patentee, and claimed by him as his invention. It consists of another pipe m, into which the discharging end of the crane-necked pipe is made to enter, and which pipe after passing the end of the trough n is made of a very broad flat shape, and running the whole length of the trough (which may be of any extent;) it is then to return by a very slight descent, so as to run back very gently into the funnel of the pipe which conveys it into the receiver.

The trough n is to be filled with Glauber's salts and nitre, or any saline mixture capable of producing intense cold, for the more effectual cooling of the spirit; the trough may be placed upon wheels and axles for the convenience of bringing it to, and conveying it from its required situation.

The patentee further recommends, but does not claim it as a patent right, that the ash-pit of this still, as well as of stills generally, be furnished with a plate iron door, in which is to be introduced near its top one or more registers as shewn in the separate figure at o, the apertures in which are to be sufficiently large when open to admit the necessary volume of air to feed the fire, but which may be closed more or less to produce the required draught, and thereby enable the distiller to check or increase the ebullition at pleasure and with the greatest facility.

History of the Steam Engine, Chap. IV.
Continued from p. 287.

MURRAY'S AIR PUMP.-NUNCARROW'S ENGINE.

At the same time Mr. Murray described a new air-pump, in which the air in the condenser was discharged from the air-pump without an effort to open the valves, or press through a body of water, and

in which the air and water were discharged, separately, in different ways; this he effected by discharging the air alone by one bucket, and the water alone by another, or by an eduction pipe of 28 feet in length. A represents the condenser; B the air-pump; C the air piston; D the air valve which is opened and shut by the working parts of the engine, and has an elastic rod; E the valve for discharging the air; F the exhausting" pipe, having a free communication betwixt the condenser and the top of the air pump, when the valve D is open; G the eduction pipe; K a bucket for lifting the water upwards as in a common pump; La foot valve for preventing

a return of the water during the descent of the bucket K; M the barrel of the pump for discharging water alone. This, together with an inspection of the preceding diagram, will serve to shew the nature of his invention. The utility of the separate discharge of the air and water is unquestionable; but whether this will compensate for the increased expense and complexity can only be ascertained in practice. Mr. Murray's scheme, however, has been again made the subject of a patent, a short time ago, by Mr. George Stephenson, of Newcastle.

In the same year (1801) Mr. Bramah obtained a patent for an improvement in the fourway cock, by causing it to make a continuous revolution instead of a partial one (as used previously). By this method the wear was more regular, which rendered the cock durable, and it was likewise more certain and correct in its action.

Mr. John Nuncarrow's engine, for giving motion to a water-wheel, by a fall obtained by the power of steam, acts upon the same principle as those of Papin and Savery, but as his machine possesses many great advantages over theirs, we shall offer no apology for its insertion.

A is the receiver, which may be made either of wood or iron. BBB BB are wooden or cast iron pipes, for conveying the water to the receiver, and thence to the penstock. C the penstock or cistern; D the water wheel; E the boiler, which may be either iron or copper; F is the hot well for supplying the boiler with water; G G are two cisterns under the level of the water, in which the small bores B B and the condenser are contained. H H H is the surface of the water with which the steam engine and water wheel are supplied; a a is the steam pipe through which the steam is conveyed from the boiler to the receiver; the feeding pipe, for supplying the boiler with hot water; cecce the condensing apparatus; d d the pipe which conveys the hot water from the condenser to the hot well; e e e valves for admitting and excluding the water; ff the injection pipe, and g the injection cock; h the condenser.

It does not appear necessary to say any thing here on the manner in which this machine performs its operations without manual assistance, as the method of opening the cocks, by which the steam is admitted into the receiver and condensed, has been already well described by several writers. But it will be necessary to remark, that the receiver, penstock, and all the pipes, must be previously filled before any water can be delivered on the wheel; and when the steam in the boiler has acquired a sufficient strength, the valve as at c is open, and the steam immediately rushes from the boiler at E into the receiver A, the water descends through the tubes A and B, and ascends through the valve e, and the other pipe or tube B into the penstock C. This part of the operation being performed, and the valve c shut, that at a is suddenly opened, through which the steam rushes down the condensing pipe c, and in its passage meets with a jet of cold water from the injection cock g, by which it is condensed; a vacuum being made by this means in the receiver, the water is driven up to fill it a second time through the valves e e, by the pressure of the external air, when the steam valve at c is again opened, and the operation repeated for any length of time the machine is required to work.