Mechanics.

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the Float G forward; and though it be an obliqueForce, it will always avail something so long as ittouches the Float; and cannot be esteemed a NegativeQuantity, as some have asserted.

26. Since many may be curious to know how theForce of Impulse and Gravity of the Water in the Buc-kets of an Ovcrjhot-Wheel is to be computed or estimatedto a Mathematical Exactness, I shall here give theMethod, and illustrate it by a Scheme. Let ABC, fsV.be the Buckets of an Overshot-Wheel, (having twen-ty-four in all) inclined to the Periphery in an Angle offorty-five Degrees : Those with Dots or Points repre-sent the Buckets with the different Quantities of Waterthey contain, among which the largest Dots in theMiddle represent the Centres of Gravity of the severalBodies of Water. Now suppose the Water comes uponthe uppermost Bucket A in the horizontal DirectionXA, though by its Curvature at entering the Bucketit cannot strike the Side of the Bucket directly, yet,since the Side of the Bucket obstructs and sustains thesaid whole horizontal percussive Force, and that underan Inclination of forty-five Degrees, we may concludethat half that percussive Force is spent in turning aboutthe Wheel.

27. As to the Force arising from every descendingBucket of Water, it may be easily determined by find-ing the Bulk of the Water in each Bucket, and multi-plying that in the perpendicular Distance of the Lineof Direction of the Centre of Gravity from the Centreof Motion. Hence, with respect to the first BucketA, since its Centre of Gravity acts in the DirectionVN, that is, perpendicularly on the Centre of Motion,that Product, or the Weight of that Bucket of Water,will avail nothing to move the Wheel round, as beingwholly supported on the Axis of Motion.

28. But the Water in the second Bucket B gravitat-ing in the Direction R O, at the perpendicular DistanceN O from the Centre, if we multiply its Mass orWeight into the Distance N O, we shall have its Mo-mentum or Force to move the Wheel; and so of anyother. Here we may observe, that as the Water in theBuckets decreases, the Distances increase from theCentre, in the upper descending Quadrant; and since

the