"In a lateral drain 200 feet long, the pipes being thirteen inches long, there will be 184 joints, each joint having an opening of six-tenth square inch area; in 184 joints there is an aggregate area of 110 square inches; the area of the opening at the end of a two-inch pipe is about three inches; 110 square inches inlet to three inches outlet; thirty-seven times as much water can flow in as can flow out. There is, then, no need for the water to go through the pores of the pipe; and the fact is, we think, quite fortunate, for the passage of water through the pores would in no case be sufficient to benefit the land to much extent. We tried an experiment, by stopping one end of an ordinary drain-pipe and filling it with water. At the end of sixty-five hours, water still stood in the pipe three-fourths of an inch deep. About half the water first put into the pipe had run out at the end of twenty-four hours. If the pipe was stopped at both ends and plunged four feet deep in water, it would undoubtedly fill in a short time; but such a test is an unfair one, for no drain could be doing service, over which water could collect to the depth of four feet." 1-1/2-INCH DRAIN-PIPE. Area: 1.76709 inches. ==================================================================== FALL | VELOCITY | DISCHARGE || FALL | VELOCITY | DISCHARGE in |per second| in gallons || in |per second| in gallons 100 feet.| in feet. |in 24 hours.||100 feet.| in feet. |in 24 hours. ---------+----------+------------++---------+----------+------------ ft. in. | | || ft. in. | | 0.3 | 0.71 | 5630.87 || 5.3 | 3.75 | 29704.51 0.6 | 1.04 | 8248.03 || 5.6 | 3.84 | 30454.28 0.9 | 1.29 | 10230.73 || 5.9 | 3.93 | 31168.06 1.0 | 1.52 | 12054.81 || 6.0 | 4.00 | 31723.21 1.3 | 1.74 | 13799.59 || 6.3 | 4.10 | 32516.36 1.6 | 1.91 | 15147.83 || 6.6 | 4.18 | 33150.76 1.9 | 2.10 | 16654.68 || 6.9 | 4.25 | 33705.91 2.0 | 2.26 | 17923.61 || 7.0 | 4.33 | 34340.38 2.3 | 2.41 | 19113.23 || 7.3 | 4.41 | 34974.85 2.6 | 2.56 | 20302.86 || 7.6 | 4.49 | 35609.30 2.9 | 2.69 | 21333.86 || 7.9 | 4.56 | 36154.45 3.0 | 2.83 | 22444.17 || 8.0 | 4.65 | 36878.23 3.3 | 2.94 | 23150.71 || 8.3 | 4.71 | 37354.08 3.6 | 3.06 | 24268.25 || 8.6 | 4.79 | 37988.55 3.9 | 3.16 | 25061.34 || 8.9 | 4.85 | 38464.40 4.0 | 3.28 | 26013.03 || 9.0 | 4.91 | 38940.25 4.3 | 3.38 | 26806.11 || 9.3 | 4.98 | 39495.39