Manufacturers should do more educational work and talk less about the wonderfully marvelous and marvelously wonderful. Salesmen should study mechanics instead of oratory. Tractor efficiency should be rated practically instead of theoretically. The few actual reports of performance have emanated from tests with new machines in the hands of trained demonstrators. Manufacturers include belt power work among the virtues of farm tractors, and they enumerate many light jobs, such as running a cream-separator, sawing wood, pumping water and turning the fanning-mill. Well, a farm tractor can do such work--yes. So can an elephant push a baby carriage. If manufacturers would devise a practical means of using electricity as an intermediary, and explain to farmers how a day's energy may be stored in practical working batteries to be paid out in a week, then we could understand why we should run a 20 horsepower engine to operate a cream-separator one hour at night and another hour in the morning. [Illustration: Figure 114.--Straight Transmission Gear, forward and chain drive reverse, for traction engine.] CHAPTER IV DRIVEN MACHINES FARM WATERWORKS Every farm has its own water supply. Some are very simple, others are quite elaborate. It is both possible and practical for a farmer to have his own tap water under pressure on the same plan as the city. When good water is abundant within 75 feet of the surface of the ground the farm supply may be had cheaper and better than the city. Even deep well pumping is practical with good machinery rightly installed. Farm waterworks should serve the house and the watering troughs under a pressure of at least 40 pounds at the ground level. The system should also include water for sprinkling the lawn and for irrigating the garden. If strawberries or other intensive money crops are grown for market there should be sufficient water in the pipes to save the crop in time of drouth. These different uses should all be credited to the farm waterworks system pro rata, according to the amounts used by the different departments of the farm. The books would then prove that the luxury of hot and cold running water in the farmhouse costs less than the average city family pays. _Three Systems of Water Storage._--The first plan adopted for supplying water under pressure on farms was the overhead tank. The water was lifted up into the tank by a windmill and force pump. Because wind power proved rather uncertain farmers adopted the gasoline engine, usually a two horsepower engine. The second water storage plan was the air-tight steel water-tank to be placed in the cellar or in a pit underground. The same pump and power supplies the water for this system, but it also requires an air-pump to supply pressure to force the water out of the tank. The third plan forces the water out of the well by air pressure, as it is needed for use. No water pump is required in this system; the air-compressor takes its place.