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SECTION VI.-WINDMILLS.

CHAPTER LXXXIII.

WIND AS A MOTOR IN THE MINING DISTRICTS.

Already the scarcity and dearness of fuel for steam machinery is a heavy expense upon mining and metallurgical operations in many of the sparsely wooded or desert mining regions of the great interior basin of this continent. In different districts, different expedients have been adopted or proposed for relief from this great and growing burden. Water-power is, of course, scanty in those places where there are no trees. If there were more water in the country, there would be more trees, and so more fuel. Devices for saving fuel in the generation of steam are much in vogue among the engineers; and, without stopping here to condemn or recommend anything of this kind by name, I would say, in general, that the construction of the boiler and fire-places is a matter of great importance in the mining districts of the far West, since a small saving in fuel, or time and labor, represents a large saving in money, where wood and wages are so high. At Virginia City, Nevada, the mill-men are helping themselves with a railroad, by means of which they will be able to obtain fuel from the inexhaustible forests of the Sierra. Along the line of the Pacific railroad, from Laramie on the east to Corinne or Elcho on the west, the fine coal of the Rocky Mountain and Wasatch beds will doubtless be introduced as a substitute for wood. It cannot be surpassed as a steam-coal; and some of the beds, it is hoped, will be found suitable for metallurgical purposes-if not for blast fur naces, at least for reverberatories.

But there are regions, for example, through Central Nevada, stretching from Cortez to Pahranagat, which are remote from railroads, waterpower, and coal-beds, and which, if their mines are developed with the vigor they deserve and will repay, are certain to experience great distress for want of motive power to drive the machinery of their mines and mills. The feeble, scattered growth of pine-nut trees in the mountain cañons of these districts will not long support an active industry. We have heard a good deal, since the new philosophy of heat came in, of utilizing the heat of the sun. Captain Ericsson's famous letter on the solar engine, which he proposes to construct, and by which he expects to transform radiant heat into horse-powers by the thousand, is fresh in the minds of most readers. Other (and possibly less trustworthy) inventors have plans for availing themselves of the electricity generated in the earth or the elements. Some time ago, an aspiring chemist claimed our admiration for his process for reducing ores by means of thunder-storms. But it has been abundantly shown that electricity, as a motor, is too costly to be used with profit; and, as for Captain Ericsson's solar engine, we do not yet hear of it on a large working scale. Moreover, there are one or two reasons for preferring a somewhat dif ferent utilization of the heat-power of the sun. The philosophers are agreed that great loss of power inheres in all our engines for converting heat into motion. Nature produces motion more cheaply than we can;

and our water-wheels avail themselves of her quiet economy. But there is a more direct medium than flowing water between heat and motion, namely, moving air; and in all the range of mechanical motors the windmill is perhaps at once the most neglected and the most promising.*

The windmill's weak point is its dependence upon the weather; but the solar engine would be still worse in this respect, for, taking the year together, we may say that it blows oftener and longer than it shines. Twelve hours out of twenty-four there is no sun, though considerable wind. Water-powers are also, in a less degree, open to the same objection. They stop for dry weather, cold weather, and very wet weather. Nothing but steam may be thoroughly depended upon at all times to do the full duty expected of it. But this advantage of steam is measurable in money; and at some times, in some places, the price of fuel may be so great as to overbalance it.

Moreover, it might be well worth while, in some cases, to employ some of these motors, even though a steam-engine should stand idle, waiting to be used when sun or air or water failed. Stamp mills are at present frequently built so as to be geared as need dictates, either to a waterwheel or to an engine; and it is one of the disadvantages of the "directacting steam stamp" that it must have steam, and can never be employed with cheaper motors. Besides, we are not at the end of our resources concerning the storage and equal distribution of the fitful sources of wind and sunshine. By the elevation of water into a reservoir, or by the raising of heavy weights, it would be possible to accumulate power while the motive forces were acting, and thus obtain a regular supply for what would otherwise be wasted hours. The practice of hydraulic miners who buy water of ditch companies, and let it run from the ditches into their private reservoirs for twenty-four hours, so that during the ten or twelve hours of labor they can use it in a double stream, is precisely the reverse of that to which we refer; but it proves the practicability of both. The hydraulic miner wishes to obtain a greater force during a less time, and to that end accumulates the results of a steady power during a longer time. It would be scarcely more difficult, by employing great power for a short period, to obtain results which could be beneficially distributed through the whole day. Our inventors might profitably turn themselves to the consideration of the best mechanical contrivances to facilitate this exchange of force and time. But, finally, there are many kinds of work to which machinery is applied in mining that need not be continuously performed. If windmills perform the duty of draining the low coasts of Holland, or irrigating the arid plains of California, there is no reason why they should not be so constructed and arranged as to do the pumping in many of our mines, where the depth is not great nor the amount of water excessive. I might even say that if the grist-mills could wait (as in the good old times they were fain to do) for a fair wind to do the grinding, even a quartz-mill might be run, though with much vexatious interruption, on the same rude plan. Cessations for want of wind would be less common than the reader might suppose. Precisely those regions where scarcity of fuel and water-power might lead to the expedients we are discussing are noted for their perpetual winds.

Certainly it seems a pity that men should suffer so much pains and loss by reason of the expense and difficulty of the motors to which they

* For valuable notes and suggestions in connection with this subject, I am indebted to Dr. P. H. Vanderweyde of New York, himself a native of the country of windmills, though for many years a well-known resident of the United States. Mr. Blake is not responsible for this chapter.-R. W. R.

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are accustomed, while every breeze that whistles over their heads is piping of power unheeded and running to waste. Possibly the highest science, as well as the most practical economy, may dictate a return to this motor of our fathers, and a development of its capacity in the light of that mechanical perfection which has been bestowed upon other machines. I would not be understood, however, as declaring any universal and hitherto unacknowledged superiority of windmills. It is enough to say that windmills are likely to be the best we can choose in certain cases where, before long, we shall have to choose that or nothing.

But if we would learn the best practical construction, and appreciate the great capacity, of windmills, we must look to those countries in which they have been most thoroughly studied and most widely employed. It is said that this device was brought from the Orient by the Crusaders, and introduced in the sixth century into France, Flanders, and Holland. Northern Germany, however, claims the invention, in the eleventh century, of the large post-windmills called Bock mills, which will presently be described.

But Holland is, above all, the country where this motor has been most extensively applied. The civilization of that state, nurtured into early maturity by the natural obstacles with which it was forced to contend, was for a long time in advance of that of the rest of Europe. The sea was at once its greatest benefactor and its devouring enemy. In regions possessed of a varied topography there is natural drainage, resulting in natural water power; but the low, flat surface of Holland at once demands the drainage and denies the power. Besides the necessity of power for pumping, there was also from early times grain to be ground for the food of the inhabitants, and timber to be sawed for marine and civil architecture. Long before the introduction of the steam-engine, in fact for more than a thousand years, the power of the wind has been employed by the industrious Hollanders in the performance of these duties; and even at the present day, though the great modern motor is. fully understood and appreciated in that country, the old favorite still holds its place, and Holland possesses the largest windmills and the largest steam pumping engines in the world.

Some notion of the amount of work performed by windmills in Holland may be derived from the statement that, between 1440 and 1850, more than a hundred large and small lakes, having a total area of a quarter of a million acres, were drained by this means, restoring this amount of most fertile soil to settlement and cultivation. In the drainage of the great Haarlem Lake, and of a few smaller ones, steam was introduced in 1845, but it is still an open question whether wind could not have been more economically employed. Holland possesses neither coal-mines nor forests; and steam, with all its advantages of uniform and continued availability, cannot compete in economy with wind. It has been used in the instances referred to, and is. employed as an auxiliary, or held in reserve in certain localities, where, in occasional_seasons of much rain, coinciding with little wind, the windmills in use have been found inadequate to perfect drainage.

It may be mentioned, in passing, that this region possesses large deposits of peat, and that dried peat or turf is a common fuel. The use of peat as a steam fuel has therefore been naturally a subject of much interest, and has received thorough investigation. It has been found inferior to coal, and though the densest varieties are superior (weight for weight) to wood, their greater bulk and too rapid combustion render them inconvenient and undesirable for this purpose.

Concerning the usefulness of windmills for operations requiring small

power, nothing need be said. They are extensively used on the Pacific coast in raising water for irrigation; and they might with advantage be employed generally by farmers and others for numerous domestic purposes, such as churning, turning grindstones, &c. I think their application would be more extensive in this country but for the numerous patented and more or less complicated modifications, which tend both to increase their cost and to limit their power.

There are two great classes of windmills, distinguished by the position of the sails. The vertical mills have their wings or sails so placed as to turn in a nearly vertical plane, about an axis nearly horizontal; and the horizontal mills have their wings turning about a vertical axis. The latter are far less effective, giving for the same surface of sails and strength of wind, according to Sir David Brewster, not more than onethird or one-fourth as much power as the former. They are seldom constructed, except in situations where the necessary height cannot be given to vertical sails. I have seen some of them along the Pacific railroad, employed for raising water into tanks for locomotive supply. As might be expected, they do not give satisfaction. The secret of their comparative inefficiency is the small surface exposed to the impulse of the wind at any one moment, and the interference of the wind passing through and striking the backs of the opposite sails. The mechanical contrivances intended to obviate this difficulty by a continual adjustment of the sails are liable to derangement. At all events, the vertical mills are more suitable where great power is desired, and this is the purpose to which I desire to call particular attention.

The vertical windmills may be divided again into two classes, in the first of which the whole mill building is revolved, so that the sails may

face the wind from any quarter, while in the second only a dome revolves, carrying the sails and their axis, while the building with its machinery remains stationary. The former are the post or Bock mills, to which allusion has already been made. Their construction may be understood from the accompanying illustration, which, with the two following, has been kindly lent me by Messrs. Western & Co., publishers of the Manufacturer and Builder, a pictorial monthly magazine of New York. A strong, conical tower of heavy timbers, from ten to twenty feet high, rests upon five piers of masonry. At the apex of this framework is a pivot or column of iron, fitting into a corresponding socket or box in the floor of the mill. Upon this column the mill rests and revolves. The building is entered by means of a staircase extending nearly to the ground, on the side opposite the sails, and so strongly built and braced as to furnish a convenient point for attaching the ropes or chains which anchor the mill in any desired position. A dozen posts are set firmly

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