The acceleration of gravity affects falling water in the same manner as it affects a falling bullet. At any one second, during its course of fall, it is traveling at a rate 32.16 feet a second in excess of its speed the previous second. In figuring the size wheel necessary under given conditions or to determine the power of water with a given nozzle opening, it is necessary to take this into account. The table on page 51 gives velocity per second of falling water, ignoring the friction of the pipe, in heads from 5 to 1000 feet. The scientific formula from which the table is computed is expressed as follows, for those of a mathematical turn of mind: Velocity (ft. per sec.) = sqrt(2gh); or, velocity is equal to the square root of the product (g = 32.16,--times head in feet, multiplied by 2). SPOUTING VELOCITY OF WATER, IN FEET PER SECOND, IN HEADS OF FROM 5 TO 1,000 FEET Head Velocity 5 17.9 6 19.7 7 21.2 8 22.7 9 24.1 10 25.4 11 26.6 11.5 27.2 12 27.8 12.5 28.4 13 28.9 13.5 29.5 14 30.0 14.5 30.5 15 31.3 15.5 31.6 16 32.1 16.5 32.6 17 33.1 17.5 33.6 18 34.0 18.5 34.5 19 35.0 19.5 35.4 20 35.9 20.5 36.3 21 36.8 21.5 37.2 22 37.6 22.5 38.1 23 38.5 23.5 38.9 24 39.3 24.5 39.7 25 40.1 26 40.9 27 41.7 28 42.5 29 43.2 30 43.9 31 44.7 32 45.4 33 46.1 34 46.7 35 47.4 36 48.1 37 48.8 38 49.5 39 50.1 40 50.7 41 51.3 42 52.0 43 52.6 44 53.2 45 53.8 46 54.4 47 55.0 48 55.6 49 56.2 50 56.7 55 59.5 60 62.1 65 64.7 70 67.1 75 69.5 80 71.8 85 74.0 90 76.1 95 78.2 100 80.3 200 114.0 300 139.0 400 160.0 500 179.0 1000 254.0 _In the above example, we found that 376 cubic feet of water a minute, under 13.5 feet head, would deliver 7.2 actual horsepower. Question: What size wheel would it be necessary to install under such conditions?_