Water-power is the most satisfactory of all kinds of stationary farm power, when a steady stream of water may be harnessed to a good water-wheel. It is not a difficult engineering feat to throw a dam across a small stream and take the water out into a penstock to supply water to a turbine water-wheel. In the first place it is necessary to measure the flow of water to determine the size of water-wheel which may be used to advantage. In connection with the flow of water it is also important to know the fall. Water is measured by what is termed a "weir." It is easily made by cutting an oblong notch in a plank placed across the stream, as a temporary dam which raises the water a few inches to get a steady, even flow of water through the notch so that calculations may be made in miner's inches. The term "miner's inch" is not accurate, but it comes near enough for practical purposes. Measuring the volume of water should be done during a dry time in summer. The fall of the stream is easily measured by means of a carpenter's level and a stake. The stake is driven into the ground at a point downstream where water may be delivered to the wheel and a tailrace established to the best advantage. Sighting over the level to a mark on the stake will show the amount of fall. When a manufacturer of water-wheels has the amount of water and the fall, he can estimate the size and character of wheel to supply. The penstock may be vertical or placed on a slant. A galvanized pipe sufficient to carry the necessary amount of water may be laid along the bank, but it should be thoroughly well supported because a pipe full of water is heavy, and settling is likely to break a joint. Galvanized piping for a farm penstock is not necessarily expensive. It may be made at any tin shop and put together on the ground in sections. The only difficult part about it is soldering the under side of the joints, but generally it may be rolled a little to one side until the bottom of the seam is reached. The most satisfactory way to carry power from the water-wheel to the farm buildings is by means of electricity. The dynamo may be coupled to the water-wheel and wires carried any required distance. The work of installing electric power machinery is more a question of detail than mechanics or electrical engineering. The different appliances are bought from the manufacturer and placed where they are needed. It is principally a question of expense and quantity of electricity needed or developed. If the current is used for power, then a motor is connected with the dynamo and current from the dynamo drives the motor. A dynamo may be connected with the water-wheel shaft at the source of power and the motor may be placed in the power-house or any of the other buildings.