adjustable to face the wind. The sails must of course be arranged to reef: should this precaution not be taken a gale of wind may sweep the whole erection away. The whole of the timber used should, if possible, be creosoted, or covered with an anti-rot composition, or, failing this, a good coating of tar will be beneficial.

Where mills of a large size are required it will be found far preferable to buy than to make, as in the best class of mills points are embodied in their construction, and their various parts so carefully studied out, to secure efficiency, that it would be impossible to produce them in the colonies at anything like the price charged here, even with freightage added.

Farmers and planters should, however, be able to construct a small machine for pumping, &c., without much difficulty, and we think if a little more attention were given to irrigation by means of wind power the productive power of the soil, in hot countries especially, would be largely increased. It has been urged that windmills in hot countries where there is usually little wind are failures. This is not so, as a well designed and constructed machine will work with a very light wind pressure; but a number of machines of imperfect construction having been erected and having failed to give satisfactory results, windmills as a whole have been unjustly condemned.

One of the best uses to which windmills can be put is pumping either from a well for drinking purposes or from a river for irrigation. With a suitable pump water can thus be raised from almost any depth. We shall elsewhere have something to say on the best form of pump to employ for this purpose. In calculating the power required in a windmill a considerable margin must be allowed for contingencies. Should a windmill of considerable size be used for pumping it would be as well to fit

duplicate pumps, so that when there was a stiff breeze both pumps might be employed, and when the breeze was light one might be disconnected and the other worked by itself.

As regards the selection of a windmill, the following points should always be borne in mind: 1. What power is required? 2. Where is it to be erected? 3. For what purpose is it to be used? 4. Is skilled labour for repairs, &c., available? Should the mill be required for pumping from a well, the following particulars should be given when writing to a manufacturer: 1. The depth of well or spring below the surface of the ground. 2. The least depth of water in it. 3. The height above the platform of the well to where you wish the water discharged. 4. The lateral or side distance (if any) from the supply to the place where the water is to discharge. 5. The amount or quantity of water wanted, or at least the purpose for which it is to be used; also the extent or quantity of water afforded by the supply or source. 6. The height at

which the mill must be erected to secure a free current of air; with all other particulars you can think of. It is important and should be observed that a windmill, deriving its force and power from the wind, should have as great an elevation as possible within reasonable limits, so as to obtain steady motion and the full benefit of light winds. 7. In case of a bored well, give the diameter. Should a considerable amount of power be required, and skilled labour be available, then a mill of the most improved or elaborate class should be selected; but in many cases-in the isolated settlements of Australia or South Africa-only the aid of a rough carpenter can be obtained. In these cases it would be folly to erect anything but of the simplest construction-viz., the old-fashioned four-arm vertical windmill-as these are cheap, easily repaired, and require little or no attention, and for rough pumping or

irrigation purposes cannot well be surpassed. Although this type of windmill is of the simplest, it should nevertheless be thoroughly well designed and made, to secure efficiency. If a mill is left several days without attention, as is often the case when employed for drainage or irrigation purposes, it must be arranged to both face the wind automatically and to reef its own sails, as should a sudden gale occur it may be made to revolve at a tremendous speed, possibly firing its bearings, or be swept away altogether.

In the most advanced types of windmills several important improvements have been introduced. The chief of these, which is believed to be of American origin, is an annular arrangement of the sails: these are divided into sections, which swing on pivots, and are acted on by the wind something as it does on an umbrella. For bringing the sails automatically round to meet the wind a small back fan-sail running at a high speed is usually employed.

Efficient means of lubricating the shaft bearing should be taken a mixture of powdered plumbago and tallow or castor oil (if available) and powdered sulphur will be found to answer well. These should be of a rather stiff consistency, having a larger base of sulphur or plumbago as the shaft and mill are increased in size. Windmills in some instances have been introduced on board sailing ships, and are used for pumping purposes, we believe with considerable success.

It has been calculated that a windmill with four sails, each 24 feet in length and 6 in breadth, with a wind at a velocity of 20 feet per second, is equal to 4 horse-power. Taking this as a basis, other sizes and powers may be estimated.

CHAPTER VI.

PUMPING MACHINERY.

ONE of the most important classes of machinery, and one that has been brought to a high state of perfection, is now to be briefly considered. The two chief classes of pumps are the suction-in which the water is raised by means of a partial vacuum produced in the barrel-and the force pump, which acts by compression instead of exhaustion.

A variety of bucket, chain, and other kinds of water lifts are used, which we shall briefly notice. The common lift pump is not capable of raising water from a greater depth than 30 feet below where it is fixed; it can, however, be made to force water to almost any height above its own level.

When it is required to raise water from greater depths the force pump is employed.

A considerable number of hand-power pumps especially designed to meet the requirements of colonists have been. introduced, and we are afraid some of these are of very imperfect and inferior construction. To secure efficiency they should in all cases have bored barrels and gun-metal valves and buckets, and where low prices is not an object a brass lining to the pump barrel is a decided improvement. All pumps should be arranged so that the valves and working parts can be easily examined should they choke or get out of order.

A good form of pump for estate and colonial purposes is the ordinary single, double, or treble barrel pump, espe

cially if for permanent use in one situation. These are of simple construction, easily repaired, and require comparatively small power to work them. The chain or bucket pump, too, for lifts not exceeding 40 feet, is extremely useful, and will raise a large amount of water. Should

steam power be employed it would of course depend greatly upon what was the character of the work in hand as to the best type of pump to employ. For irrigation purposes the centrifugal pump, driven by a band, has much to commend it. For drainage purposes, where the lift does not exceed 8 or 10 feet, and where pumping may be carried on intermittently, a dash-wheel water lift, driven by a self-adjusting windmill, will raise a large quantity of water with scarcely any attention, and its simplicity is much in its

favour for use in isolated districts.

The barrel pumps are constructed in a variety of forms, and for light purposes can be arranged to work by hand by means of a crank shaft with handle and fly-wheel; these will not, however, lift from a greater depth than about 30 feet. They will nevertheless be found very useful for the supply of small villages, &c. Should the well from which the water is drawn be of considerable depth, the pump must be fixed on a staging down the well and worked by a connecting rod or rods. Very great care should be exercised in fixing the pump plunger and connecting rod exactly in a vertical line: should they be out of plumb the valves will probably soon be broken to pieces—in fact, in one case we have known a valve to be broken to pieces and be brought to the surface with the stream of water. Where a considerable supply of water is required we recommend the use of a double or treble barrel pump, worked by a horse or bullock gear, or a windmill, or both alternately, or they may be arranged to work by manual power by means of levers. If the supply required is very large a steam pump should be employed.