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WHITELAW AND STIRRAT’S PATENT WATER MILL.* Fig. 1 is a side elevation of the new water-mill, in which "figure some of the parts are drawn in section. Fig. 2 is a plan showing the arms and other parts of the machine. The main pipe a a carries the water which drives the machine into its arms, from a reservoir or any suitable place on a higher level than the arms; b b are the arms, which are hollow; the water passes into them at the centre part c, and escapes out at the jet-pipes dd; ee is the main or driving shaft of the machine, which is shown cast in one piece with the arms; fis a bevel pinion, and g a bevel wheel; by means of which wheel and pinion the rotary motion of the machine is communicated to the hori zontal shaft h, which again communicates the power of the machine to any machinery which it may be intended to work; Hi is a large bracket fixed to the wall or building kk; this bracket supports the shaft ee, while the bracket l carries one end of the shaft h. The per pendicular plane which passes through the parts represented in section in the elevation, Fig. 1, passes through the points m in in the plan, Fig. 2. The top journal or bearing n of the main shaft has a number of collars on it; for, if there were but one collar, it would require to be made larger in diameter than the collars shown in Fig. 1, in order to get a sufficient quantity of bearing surface; but if the diameter of a collar be increased, the friction will be greater, as then the rubbing surface is more distant from the centre of motion; so, if a sufficient quantity of bearing surface is obtained by a number of collars, there will-be less friction than if only one is used to resist the pressure. q q are holes through which the water escapes from the basin under the arms into the tailrace after it has left the machine. As the arms have a rotary motion, and the pipe a a is fixed to the building under it, there must be means provided to prevent the escape of water at the place where the main-pipe meets the arms. A contrivance suit able for this purpose is shown in Fig. 1; it consists of a ring or pro jection round the underside of the aperture c, and of a part p turned cylindrical at the place where it fits into the pipe a a. A leather, * AY c arc indebted for this description to a pamphlet by James AVhitelaw, and for tl.c use of the wood engravings to the Editor of the Mechanics’ Magazine. similar to what, is used in packing the large piston in a Bramah press, is inserted into the recess w w, turned inside of the top part of the pipe a a, in order to prevent the escape of water betwixt the pipe and the cylindrical part of p. It will now be clear that if the part p, and the ring on the underside of c, are accurately turned and ground upon each other at the place where they meet, the pressure of the water in the main pipe will act upon the under edge of p, and press it in contact with the projecting part round the aperture c, and in this way keep the joining of those parts water-tight. There is a flanch outside of p, with holes bored in it, to receive steadying-pins fixed to the top part of the pipe a a; these pins are seen in Fig. 1; they prevent the part p from revolving, and are fitted so as to allow p to rise or fall. There is another use for the flanch roundp, which is this:—a little rope-yarn is wrapped betwixt it and the main pipe, to prevent the part p from sliding down whenever there is not a sufficient pressure of water in the main pipe to support it. The pipe a a is bored out to receive the party?, which is fitted so as that it will slide easily up or down in the bored part; rrrr are the stay-bolts which support the arms; s s are valves, and s t s t are levers which work upon the centres 11, and form a connexion of these centres with the valves. There is a. lever on the top, and one on the bottom side of each valve. The rods u u form a connexion with the levers s t s t, and the springs r v v v, fixed to the arms. The end next the valve of each jet-pipe (see Fig. 2) is a circle drawn from t as a centre; and each valve is curved to fit and work correetly upon the end of its pipe. The levers sis t arc adjusted so that the valves s s will work w ithout rubbing upon the ends of the jet-pipes, in order to get quit of the friction as much as possible; but it is not essential that the valves should be correctly water-tight. It will be clear, that if the machine revolves so fast as to make the united centrifugal forces of the valves s s, the rods u u, the levers s is /, and the springs, greater than the weight that will bend the springs v v vv to the distance shown in Fig. 2, the valves will recede from the centre of the machine till the force of the springs gets sufficient to overcome the centrifugal force of the valves, &c. Therefore, the centrifugal force will cause the valves to cover the ends of the jet-pipes, and so allow less water to escape, and thus diminish the force of the water on the machine whenever it goes quicker than the proper speed. If the springs are considerably bent
