EXPERIMENTS BY THE FRANKLIN INSTITUTE OF PENNSYLVANIA TO ASCERTAIN THE VALUE OF WATER AS A MOVING POWER.

First Report.

(Continued from Page 132.) Frame supporting the Wheel.

N, O, P, Q, represents the frame supporting the water-wheel: this frame was formed on one side of the wheel, (Figs. II. and III.) by a double row of uprights, and on it the head-block, n", n' (Fig. II.) was placed to sustain the plumber block, o', on which one end of the axis of the wheel rested; on the other side (Figs. I. and III.) a single row of uprights braced from the floor, and connected at top and bottom, formed the frame; this was surmounted by the head block, n, n', upon which rested the plumber block, o, carrying the axis of the wheel. The frame was disconnected from the forebay.

Reservoir for collecting and measuring

the water used, Tail race, &c.

A reservoir, R, S, T, Q, (Figs. I. II., and R, R, Q, Q, Fig. III.) for collecting and measuring the water used in experiment, was made by planking the interior of part of the frame just described; the sides and ends of the reservoir were carried to the height of six feet, and the floor was laid upon the cross-sills, into which the uprights of the frame were tenanted.

This reservoir having been formed accurately into a rectangular prism, its capacity was calculated by measuring the length, breadth, and depth: to test the accuracy of the result, the reservoir was filled up to a certain level, with water carefully weighed, the number of pounds which the whole reservoir would contain calculated, a nd found to differ but 20lbs. in 30,000, from the weight obtained by means of the capacity.

To indicate the level of the water in this reservoir, with a view to determine the quantity used in any experiment, a hollow tin vessel, p, p', (Fig. I.) was used as a float; a tube passed through the axis of the float, forming a stem, which was allowed to slide freely in a vertical direction upon an iron rod, or guide, attached to the bottom of the reservoix the stem, q, q' of the float ex

tended to a convenient height above the lower floor, N, O, and was graduated into divisions, each of which represented a quantity of water within the reservoir of 1000 lbs. in weight. A light bar of iron, r, r', was attached to the upper timber of the wheel frame, having at its upper end, r, a loop embracing the stem of the float; to this loop was affixed a sliding plate of brass, r, "", the edge of which could readily be placed opposite to that mark, on the float rod, which might happen to be next_above the loop; this mark then served as a point from which to estimate the quantity of water used in any experiment without, before commencing, actually emptying the reservoir. The number of divisions on the stem of the float which had passed the top of the slide during an experiment, showed within certain limits of accuracy, the quantity of water which. had entered the reservoir; but for greater nicety of determination, a gauge plate minutely divided was applied to the top of the slide by the use of which the quantity of water in the reservoir could be obtained to within 5 lbs.

To

The water after leaving the wheel was conducted through a slightly-inclined tail-race, U, R, to the reservoir. prevent agitation of the surface of the water, within the reservoir, which would have resulted from the fall of water introduced from the tail-way, a flume R, s, s', Q, (Figs. I. H., and s, s, s', s', Fig. III.) of a square section, was constructed, extending from the race nearly to the bottom of the reservoir, between which and the termination of the flume the water must necessarily pass; there was also a platform of light boards, nearly as large as the floor of the reservoir, placed within, which rose and fell with the surface of the water; these precautions so far preserved the float from oscillation, that the operator could obtain without delay by inspecting the gauge rod, the weight of water collected in the reservoir.

To empty the reservoir, a waste valve, t, (Figs. II. and III.) was placed at one end; this valve could be opened by the lever, t', t', (Fig. II.) having its fulcrum at t'", acting upon the valve by the intervention of the rods, t't, t, t, (Fig. III.) and lever t1, t5; it was raised above the floor, so that the reservoir might never be entirely emptied, and that thus a level

W

W

z

IR

1.Q

DL

would always be afforded from which to reckon the quantity of water which entered during any experiment.

As only the water used in experiment was to be admitted to the reservoir, a valve u, u', (Figs. I. II. and III.) 15 inches in breadth, and in length equal to the breadth of the wheel, was placed in the floor of the tail-race; this valve, when open, allowed the water from the wheel to fall into a trough, u, u, v, v', v", v", (Fig. III.) which conducted it on the outside of the reservoir, by the trunk w, w', (Figs. II. and III.) to the waste trough. Guide boards were placed

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in the tail-way on each side of the valve, that all the water might pass through it when open. The closing and opening of this valve were effected by the action upon the stem x, x', (Figs. I and III. of a series of levers, (Figs. 111. and II.) x', x", y, y', y, z, connected by vertical rods, a", y, and y', y", and terminating in the stem z, z', on the side of the forebay shown in Fig. I.; by means of a handle, z", attached to this stem the operator on the first floor, N, O, O', was enabled to work the valve. When the valve was closed, the water flowed over it to the lower end of the tail-race, whence it passed, in the manner already described, to the reservoir. A bell, a, (Fig. I.) attached by a spring to the stem, z', ringing when the stem was moved, served to give notice of the closing or opening of the tail-way valve that is of the beginning or end of an ex' periment. As in closing the valve, in commencing an experiment, the small quantity of water between it and the wheel, not used in the experiment, entered the reservoir, so on opening it, at the conclusion, an equivalent quantity of the water which had been used ran to waste.

The water carried up by the wheel when in motion, was returned to the tailrace by the guard, b, b', u', (Figs. I. II. and III.) placed for this purpose, and conducted to the reservoir, or allowed to run to waste according to the position of the valve.

Water-Wheel.

V, W, U, X, (Fig. I.) represents the water-wheel used during the first series of experiments; this wheel was 20 feet in diameter, and 20 inches in breadth, being 16 inches in the clear, between the rims or cants. The rims were attached to the arms in the usual manuer. The axis of 12 inches in diameter, into which the arms entered, was surrounded, for a certain portion of its length, as shown in Plate III., by a barreling of 24 inches in diameter, the gudgeons, 3 inches in diameter, turning upon brass bearings, fitted into cast-iron plumber blocks; the whole rested on the head blocks n, n', n", n"", (Figs. I. and II.) capable of sliding upon the upper beam of the frame supporting the wheel, by which arrangement the wheel might be removed from

the breast when alterations were required.

On the inside of the head block, at n, Fig. I., an iron pin was fixed, connecting two straps, also of iron, in the manner of a joint hinge; these straps embracing the barreling of the shaft had their ends, d and d', connected by a wooden lever, d', d", turning upon a fulcrum, d", equi-distant from the ends which the lever connected; the pin forming the fulcrum passed through a post attached to one end of the head block; by depressing the erd d", of the lever, d', d", the straps were caused to press against the barrel with such force as to regulate, at the pleasure of the experimenter, the retrograde movement of the wheel produced by the descent of the weight which had been raised in any experiment; by elevating the same end of the lever, the straps were removed from contact with the barrel, which was thus permitted to revolve freely.

The buckets of the wheel having been varied in the different experiments will be described in detail in an after part of this report.

Apparatus relating to the Measure of
Effect.

Y, Y', Y", and Z, Z', Z", (Figs. I, and III.) represents two masts, or heavy posts, one of which was stepped upon the ends of two adjacent cross-sills of the forebay, at Y, the other at Z, upon a strong piece of timber, bolted to the side of the frame, supporting the wheel. From the cap, Y", Z", (Fig. III.) connecting these posts, were suspended two iron pedestals, e, e', and f, f', in which, in brass bearings, turned the gudgeons of a roller, or drum, e', f'; the gudgeons were 1 inch and 7-8ths in diameter. The drum, 16 inches in diameter, was covered with hoop iron, to prevent its abrasion by the chain which passed over it. The chain was attached at one end to the barreling of the shaft of the water wheel, and passing over the drum above, the other end, g, was fastened to a basket, g, g', of iron in which were placed the various weights used in the experiments. To prevent inequality in the weight raised during any part of an experiment, from the winding of the chain upon the barrel, a similar chain. the lower part of which always rested on

the ground, was fastened to the bottom of the basket.

The chain was kept from riding and chafing, as it wound upon the barrel, by depressing slightly the end f', of the roller, thus giving the chain a tendency to move, in winding, towards the depressed end. The chain was brought back to its original position, at the higher end of the drum, during the descent of the basket, by inclining that part between the drum and barrel in an angle, to the axis of the drum, measured towards the elevated end, less than a right angle: to give this inclination a pulley, k, (Figs. III. and I.) was fixed in an iron frame, k', k", capable of sliding in horizontal guide grooves; by drawing the frame towards 1, the pulley was made to press against the chain effecting the object proposed. The iron frame k', k", was drawn towards 1 by a rope, one end of which was attached to the frame at k", while the other passed over a fixed pulley, 1, and was attached to an axle turned by the arms, m, m', and m, m". The frame was carried back to the end, n, when the power ceased to be applied at the arms, m, m', m, m", by a weight n', acting by the rope, n', n k', passing over the pulley n, and attached to the frame at k.

The measure of effect adopted was, as has been stated, the weight raised, and the height through which it was raised; to determine this height a mark was fixed to the chain at a point convenient for beginning the experiments, and a second to serve as a point of termination. To enable the operator to judge accurately of the arrival of these points on a level with his eye, an indicator, p, p', p", (Fig. I.) being a miniature crane, was attached to the side of the forebay frame, the horizontal arm being placed at the proper height above the lower floor O, O'; the habitual position of the indicator was, as shown in Fig. I., with the horizontal bar resting against the forebay frame. Just before the arrival of the lower mark upon the chain, at the level of the indicator, it was turned at right angles to the side of the forebay; when the mark reached the indicator, the stem, z, z', of the lever for manoeuvring the gate in the tail race, was raised into the position represented in the figures, ringing the bell a; the ringing of this bell, and the closing of the