Page:Popular Science Monthly Volume 18.djvu/234

222 allows this to be done by hand when desired, through a lever upon the lower end of the rod 25. This movement is the one which takes place when the wind-pressure upon the small vane is sufficient, the wheel swinging round toward the rudder-vane an amount proportional to the pressure. When this pressure is great the wheel swings parallel with the rudder and presents only its edge to the wind, as in the case of the other vane-mill. The weight 13 is movable upon the lever 26, and the wheel is therefore capable of nice adjustment.

Windmills have gone very largely into use in the Western States, where the wind can be counted on with tolerable certainty. They are also used to a considerable extent in the East, both in the country and in the cities. Makers of wheels claim that in most localities they will work up to their full power seven hours out of the twenty-four, and a good portion of the remaining time will give some part of their full capacity. When a steady and continuous power is required, either at a definite time or whenever you happen to want it, the windmill is not suitable; but for all uses in which such conditions do not hold, such as pumping water, it is admirably adapted. It is for this purpose employed on railroads, the farm, country seats, and to some extent in cities where the water-pressure is insufficient to carry the water to the upper stories of buildings, as many as five hundred being employed in New York City alone for this purpose. On the farm it would seem that a mill might be employed for a variety of purposes besides the pumping of water. Such operations as sawing wood, chopping feed, and perhaps churning, might readily be done by wind-power, by timing them to the periods when experience showed it could best be depended upon. With a well-constructed automatic mill of from two to five horse, such work could probably be performed with less trouble than in any other way. The only expense after the first cost is that for repairs and lubrication, neither of which is large. The power of any wheel depends, of course, on the velocity of the wind. They are usually rated with the wind at twenty miles an hour, and on this basis the powers of those made range from one eighth to forty horse, the smaller size being eight and a half feet in diameter and the latter sixty. The first cost of a good mill is from twenty-five to fifty per cent, higher than a steam engine of corresponding power, with boiler.

While the windmill is peculiarly well adapted for pumping and allied purposes, it is not at all suited to most of the uses for which a small power is required. Water-power, on the other hand, is excellently adapted to such uses. Water-wheels are simple, easily managed, and the most efficient of known motors. They are especially suitable for use in the household, and, where sufficient water can be procured under a proper pressure, are at once the cheapest and most convenient motor for the shop. Water-wheels of large power, such as are required in manufacturing operations, can only be used in particular localities; but those of comparatively small power can, owing to the very general