For each pair of 4-feet stones, with all the necessary dressing machinery, etc, there is required 15 horses' power.

One pair of 4-feet stones will grind about 5 bushels of wheat per hour. Each bushel of wheat so ground per hour requires .87 actual or 1.11 indicated horses' power, exclusive of dressing and other machinery.

Stones, 4 feet diameter, 120 to 140 revolutions per minute.

Dressing Machines, 21 inches diameter, 450 to 600 revolutions per minute.

Creepers, 3½ inches pitch, 75 revolutions per minute.

Elevator, 18 inches diameter, 40 revolutions per minute.

Screen, hi inches diameter, 300 to 350 revolutions per minute.

788 cubic feet of water, discharged at a velocity of 1 foot per second, are necessary to grind and dress 1 bushel of wheat per hour = 1.49 horses' power per bushel.

2000 feet per minute, for the velocity of a stone 4 feet in diameter, may be considered a maximum speed.