Various alterations and improvements have been made from time to time in the construction of Fire-engines. The contrivers of some of these improvements, as Messrs. Bramah, Dickenson, Simpkin, Rowntree, and Phillips, have secured their inventions from infringement by patents; the specifications of most of which may be seen in the Repertory of Arts and Manufactures. In the year 1785 the silver medal and twenty guineas were conferred by the "Society for the Encouragement of Arts," &c. on Mr. Furst, as a reward for his contrivance to increase the effect of engines in extinguishing fires; of which the following is a short description: from a platform rises an upright pole or mast, of such height as may be judged necessary; a gaft slides upon it in an ascending direction, and along both is conveyed the leather hose from the engine. The branch or nose-pipe of the engine projects at the extremity of the gaft; towards which an iron frame is fixed, whence two chains are suspended; and from these hang ropes, which serve to give an horizontal direction to the branch; while other ropes, that run through proper pullies, and are thus conveyed down the mast, serve likewise to communicate a vertical motion to it. By these means, the branch or nose-pipe of the engine is conducted into the window of any room where the fire more immediately rages; and the effect of the water discharged is applied in the most efficacious manner to the extinguishing of the flames.

A very cheap and simple fire-engine is that invented in America by Mr. Benjamin Dearborn, who communicated it to the American Academy of Arts and Sciences, from whose Memoirs for 179 we extract the following particulars:

Fig. 4 p. XV. AB and CD are the edges of two planks, confined by four bolts; a b and c d are two cylindrical barrels, in each of which a piston, with a valve, is fastened to the spear e, and is moved up and down alternately by the motion of the arms EE. Beneath each barrel a hole is made through the

plank AB, which is covered with a valve. The arms EE are suspended on the common centre f: there are also arms parallel to these on the opposite side: gg are the ends of handles which are fastened across the ends of the arms. Ath a bolt goes across from arm to arm, to which the piece ik is affixed, and on which it plays; the lower end of this piece is fastened to the top of the spear e. clf is a standard for the purpose of supporting the arms, to which there is a correspondent one on the opposite side; both are notched into the edges of the planks, where they are secured by a bolt, which passes through them at 7, and hás a nut or fore-lock on the opposite side. HI, HI, are square braces, answering the purpose of ducts, through which the water ascends from the barrels, passing through the plank at m. KL, are irons in the form of a staple, in order to confine the braces the lower ends of these irons meet, and are secured by a bolt passing through them, and MNno, which is a piece that goes up through a mortice in the centre of the planks. This piece is square from the lower end, till it reaches the top of the braces; whence they become cylindrical to the top, the upper end being perforated sufficiently low down, in order to communicate with the braces. OP is an iron ring that surrounds the tube, and has two shanks which ascend through the head, which screws on the top at pq; rs is a ferule nailed round the tube.

KL,

Fig. 5. is the same engine; the arms and standards being taken off, in order to delineate more clearly the mode of securing the braces; an object which is completely effected by a wedge driven into the mortice a: beneath the upper plank b is a hole for admitting a passage to the bolt, which secures the standards. In this figure a side view of the head is given, with the pipe in a perpendicular direction.

The machine is confined within a box, set on wheels, as in the common fire-engines. The whole is made of wood, excepting the spears of the pumps, and a few bolts, &c. The advantages of this machine are, that it can be made in any place where common pumps aremanufactured; that the interior work will not exceed one-fourth of the price of those which are constructed on the usual plan; and that they are incomparably more easy to work than the common ones: circumstances which strongly recommend the American fire-engine to the attention of the public.

FLAX-MILLS have been constructed in great variety: but one of the best we are acquainted with is described in Gray's Experienced Millwright, in nearly the following terms.

CC,

Fig. 1. pl. XVI. is the plan. AA, the water-wheel. the shaft or axle upon which it is fixed. BB, a wheel fastened

upon the same shaft, containing 102 teeth, to drive the pinion D, having 25 teeth, which is fixed upon the middle bruisingroller: E, a pinion in which are 10 teeth, turned by the wheel B, which is fastened upon the under end of the perpendicular shaft that carries the scutchers. MM, the large frame that supports one end of the shaft c, and the perpendicular axle. NN are frames in which the rollers turn that break or bruise the rough flax. IA and L, the machine and handle to raise the sluice when the water is to be let on the wheel AA to turn it round. GG, doors in the side-walls of the mill-house. IK, windows to lighten the house. HH, stairs leading up to the loft.

Fig. 2. Elevation. AA, the water-wheel upon its shaft cc, on which shaft the wheel BB is also fixed: this latter wheel containing 102 teeth, to turn the wheel E, having 25 teeth, which is fastened upon the middle bruising-roller. FF is a vertical shaft, upon the lower end of which is fixed a pinion having 10 teeth, which is driven by the wheel B. There are two arms that pass through the shaft F; and upon these arms are fastened, with screwed iron bolts, the scutchers that clear the refuse off the flax. DD, the frames which support one end of the axle c, the vertical shaft, and the breaking rollers: L, a weight suspended by a rope, the other end of which is fastened to a bearer, as is seen in fig. 3. ss a lever, the short arm of which is attached to the frame that the gudgeons of the upper roller turn in; and by pushing down the long arm, the upper roller is, when necessary, so raised as to be clear of the middle one. NN, the end walls of the mill-house. RR, the couples or frame of the roof. H, a door in the side-wall. 1K, windows.

Fig. 3. Section. AA, the great water-wheel fixed upon its shaft, and containing 40 aws or float-boards to receive the water which communicates motion to the whole machinery. BB, a wheel fastened upon the same axle, having, as before mentioned, 102 cogs, to drive the wheel c of 25 teeth which is fixed upon the middle roller, No. 1. The thick part of this roller is fluted, or rather has teeth all round its circumference. These teeth are of an angular form, being broad at their base, and thinner towards their outward extremities, which are a little rounded, to prevent them from cutting the flax as it passes through betwixt the rollers. The other two rollers Nos. 2. and 3. have teeth in them of the same form and size as those in the middle roller, whose teeth, by taking into those of these two rollers, turns them both round. The rough flax is made up into small parcels, which being introduced betwixt the middle and upper rollers, pass round the middle one; and this either having rollers placed on its off side, or being inclosed by a curved board

that turns the flax out betwixt the middle and under rollers, when it is again put in betwixt the middle and upper one, round the same course, until it be sufficiently broken or softened, and prepared for the scutching machine. The bearer in which the gudgeon of the roller No. 1. turns is fixed in the frame at c; and the gudgeons of the rollers Nos. 2. and 3. turn in sliders that move up or down in grooves in the frames ss. The under roller is kept up to the middle one by the weights DD, suspended by two ropes going over two sheeves in the frames ss; their other ends being fastened to a transverse bearer below the sliders in which the gudgeons of the roller No 3. turn. The weights DD must be considerably heavier than the under roller and sliders, in order that its teeth may be pressed in betwixt the teeth of No. 1. to bruise the flax when passing between the rollers. The whole weight of the roller No. 2. presses on the flax which passes between it and No. 1. There is also a box fixed on the upper edge of its two sliders to contain a parcel of stones, or lumps of any heavy metal, so that more or less weight can be added to the roller, as is found necessary. oo, is the large frame that supports one end of the shaft which carries the two wheels A, B, and vertical axle FF; on the lower end of which is fixed the pinion turned by the wheel B, and having 10 teeth. In the axle F are arms upon which the scutchers are fastened with screwed bolts, as seen at GG, fig. 2. These scutchers are inclosed in the cylindrical box EE, having in its curved surface holes or porches at which the handfuls of flax are held in, that they may be cleaned by the revolving scutchers. HH, the fall or course of the water. TT, the sluice, machine, and handle, for raising the sluice to let the water on the great wheel. The gudgeons of the axles should all turn in cods or bushes of brass. KK, the side-walls of the mill-house. GG, doors. LL, windows.

FLOUR-MILLS are put into motion in various ways: sometimes the first mover is wind, at others water, at others the force of steam, at others the muscular energy of animals. See Footmill, Hand-mill, Wind-mill, &c.

The mechanism of the grinding part of most of these is nearly the same, and well understood: so that it will not be necessary to enter much into minutiæ, but merely to present a general description of a well-constructed mill, with any first mover; and subjoin to this description some remarks, rules, and tables.

In plate XVII. we have given a section of a double Flourmill, reduced from Gray's Experienced Millwright, with the following account. AA, the water-wheel. BB, its shaft or axle. cc, a wheel fixed upon the same shaft, containing 90 teeth or cogs, to drive the pinion No. 1. having 23 teeth, which

is fastened upon the vertical shaft D. No. 2. a wheel fixed upon the shaft D, containing 82 teeth, to turn the two pinions FF, having 15 teeth, which are fastened upon the iron axles or spindles that carry the two upper mill-stones. EE, the beam or sill that supports the frame on which the under mill-stones are laid. GG, the cases or boxes that enclose the upper millstones; they should be about 2 inches distant from the stone all round its circumference. TT, the bearers, called bridges, upon which the under end of the iron spindles turn. These spindles pass upward through a hole in the middle of the nether millstones, in which is fixed a wooden bush that their upper ends turn in. The top part of the spindles, above each wooden bush, is made square, and goes into a square hole in an iron cross, which is admitted into grooves in the middle and undersurface of the upper mill-stone. By this means that stone is carried round along with the trundles FF, when turned by the wheel No. 2. One end of the bridges TT is put into mortises in fixed bearers, and the other end into mortises in the bearers that move at one end on iron bolts, their other ends hanging by iron rods having screwed nuts, as UU; so that when turned forward or backward they raise or depress the upper mill-stones, according as the miller finds it necessary. ss, the feeders, in the under end of each of which is a square socket that goes upon the square of the spindles above the iron cross or rind, and having three or four branches that move the spout or shoe, and feed the wheat constantly from the hoppers into the hole or eye of the upper mill-stone, where it is introduced betwixt the stones; and by the circular motion of the upper stone acquires a centrifugal force; and proceeding gradually from the eye of the mill-stone towards the circumference, is at length thrown out in flour or meal. RR, the sluice, machine, and handle, to raise the sluice, and let the water on the wheel A to drive it round. No. 3. is a wheel fixed upon the shaft D, containing 44 teeth, to turn the pinion No. 4. having 15 teeth, which is fastened upon the horizontal axle н. On this axle is also fixed the barrel K, on which go the two leather belts that turn the wire engine and bolting mill. L, an iron spindle, in the under end of which is a square socket that takes in a square Onl the top of the gudgeon of the vertical shaft D. There is a pinion м, of 9 teeth, fixed on the upper end of the spindle L, to turn the wheel MM, having 48 teeth, which is fastened upon the axle round which the rope zz rolls, to carry the sacks of flour up to the cooling benches. By pulling the cord oo a little, the wheel MM and its axle are put into motion, in consequence of that wheel and its axle being moved horizontally, until the teeth of the wheel are brought into contact with those of the pinion at