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An English acre consists of 6,272,640 square inches; and an inch deep
of rain on an acre yields 6,272,640 cubic inches of water, which at
277,274 cubic inches to the gallon makes 22,622.5 gallons; and as a
gallon of distilled water weighs 10 lbs., the rainfall on an acre is
226,225 lbs. avoirdupois; counting 2,240 lbs, as a ton, an inch deep
of rain weighs 100.993 tons, or nearly 101 tons per acre. For every
hundredth of an inch a ton of water falls per acre.