fixed, eeee, to work into the bevelled wheel; fig. 132, whose teeth decline from the centre in proportion as these work from it, which declination must be reversed when the sails turn in the contrary way, gudgeons to run into irons either projecting from the ring or fastened to the shaft-head like the other cylinders. The gudgeons g keep these cylinders steady in the cross iron h at the point of the whips, and stays of any shape or number will keep them from springing.

and

Now, suppose the mill fully clothed, as at 3, all the parts of the machinery revolve with it undisturbed until a lever, fig. 136, which is fastened to the braces or fencing, by the centre pin a, fig. 137, on which it turns, and whose end b is weighted to hang down towards the breast of the mill, is brought into an horizontal direction by pulling a string attached to the end a within-side the mill, which end b stops the stud b, projecting from the inner surface or back-front of the spur-wheel, fig. 135; consequently the four spur-nuts a, at the end of the spindle, fig. 134, and seen at aaaa, fig. 135, roll round the spur-wheel, and the bevelled nuts 6 at the other end of the spindle work into the bevelled wheels of the outside cylinders iiii, at 1, 2, 3, in a straight direction behind them, and so turning the cylinders roll the cloth on them till it is rolled up to the whip. The lever is then driven sideways (its spring c returning it again) from the stud in the back face of the spur-wheel by the following contrivance:

A screw, b, fig. 138, is cut on the gudgeon of any one of the cylinders behind the sail, and a piece of iron, c, is tapped to fit it. The end of this iroa runs into a slot in the iron d, made fast to the shaft-head, to prevent the iron e from turning with the cylinder, but allows it to slide up and down so as to press on that on the iron a, which has the eye in it, and raises the end a just high enough to drive the lever aside when the cloth is all rolled up, the thread of the screw adjusting it to what number of revolutions you choose to employ for that purpose. The point-end of the irona, is that part of it which pushes aside and passes the lever, fig. 136, and moves on its centre c, and must be carried under the spur-wheel so as to act behind it for that purpose. By letting go the string the miller may at any time leave the cloth on the sail where he chooses, likewise the sails may be clothed, or any part thereof, by a lever, similar to a, stopping the stud a, on the edge of the bevelled wheel, fig. 132, and driven off in a manner similar to the spur-wheel.

Fig. 139 is a stay of wood, fixed to the stock or whip at n nnn, 1, 2, 3, to prevent the cylinders from springing too much. In the inside there is left room enough for the cloth to be rolled upon the cylinder through its lips in the eye of this stay. In order to keep the strings, which go over the edge of the shrouds oooo, &c. tight in all weathers, a cord, passing over a spring of any sort or shape, placed under the sail, is fastened to and wound about the upper ends of the cylinders, in a direction contrary to the strings and cloth. To prevent the strings from being driven downwards by the centrifugal force, a ring or two are left on to run along the rods in the old manner as p, Nos. 2, 3.

The width of the cloth, diameter of the cylinders, and number of revolutions you choose to employ to roll up your cloth, must determine the size of the wheels. In order to fold the cloth instead of rolling it, one end of it must be fastened to the whip and lines passed across the outside of it through loops fastened to its edge, and consequently over the edge of the shrouds, and connected with the cylinder or

roller, of any shape, placed under the sail, or elsewhere, the other ends of the lines must be connected with the said cylinder or roller; and when the cloth is drawn up in folds towards the whip, so much of these lines will be rolled on the cylinder one way, and off from it the other, as will be sufficient to let out the cloth again when the same cylinder, turning the contrary way, draws the cloth on the sail. By this mode the patentee gets rid of four cylinders, with their appendages, the work being in other respects the same as in rolling the cloths; but since folding gives a surface much inferior in many respects to rolling, and induces inconveniences and accidents from which the rolled surface is free, he advises the rolling, rather than for a small saving to endure the inconveniences of folding.

If a sudden gust of wind should arise in the absence of the miller, so as to drive the mill faster than a given velocity, a pair of centrifugal balls, like the governor of a steam engine, may be so placed as to adjust the lever so that it may immediately unclothe itself.

BAINES'S VERTICAL WINDMILL SAILS.

MR. ROBERT RAINES BAINES, of Myton, Kingston upon Hull, secured to himself in June 1815, by patent, an improvement in the construction of vertical windmill sails.

Fig. 140 represents six sails; the stocks or arms marked A are the same as used for common vertical windmills; the sails marked B are made of canvass, and fastened to the front sides of the said stocks or arms along the edges marked a, a, and to the rods or bars marked D, at or near the point marked b, and are also extended by the rods or bars marked E, which are inserted into or fixed to the backs thereof, and by rods or bars marked m, which are inserted into or fastened to the edges of the said sails; each sail is also connected by a bar or rod marked F, as hereinafter described, with the next following sail. The shafts or rods marked C are fastened to the stocks or arms marked A, at or near d, d, by loops or otherwise, so as to allow them to move as hinges do. The bars or rods marked D are each of them connected with the shafts or rods marked C by a joint, which will allow the said bars or rods marked D to move from the wind independent of the shafts or rods marked C, in case it should blow against the back sides of the said sails, but will not allow the said bars or rods marked D to move from the wind independent of the said shafts or rods marked C, when the wind blows against the front sides of the said sails. The bars or rods marked F connect the corners marked e of each sail with the corner of the next following sail at or near the point marked b, leading behind such following sail, and which bars or rods are fastened by hooks, or other proper means, at or near their points, bent to such an angle that if the wind should blow against the back sides of the said sails and force them forward, the said bars or rods will be unhooked and set at liberty A rim or circle marked G is fixed by screws or otherwise upon the said stocks or arms marked A, for the purpose of supporting the fulcra or props marked II. At I is represented the head or end of a rod or bar which passes through

the centre of the axletree of the mill, and to which weight may be applied, in the manner well known to mill-wrights, to regulate the said sails towards or from the wind. The bars or cranks marked K are fixed to the shafts or rods marked C, at such an angle, and in such a manner as will, when and as they are acted upon by the levers or bars marked L, either suffer the said bars or rods marked D and the sails to recede from the wind until the said sails present only their edges to it, or will force the said bars or rods marked D towards the wind, until they present to it their breadth. The levers or bars marked L are connected at one of their ends with the head of the aforesaid rod marked I, and at the other ends with the bars or cranks marked K, and form levers resting or acting upon the fulcra or props marked H, and are governed or regulated in their action by the said rod, the head of which is shown at I. The said rods, bars, cranks, loops, and rim, may be made of iron, or other suitable material or materials, and connected at their proper places by joints or otherwise, (so as to fix them or allow their action,) by modes well known to mill-wrights.

CUBITT'S METHOD OF EQUALIZING THE MOTION OF THE SAILS * OF WINDMILLS.

MR. WILLIAM CUBITT, of North Walsham, Norfolk, engineer, took out a patent for this invention in May 1807, which the specification thus describes:

"My invention consists in applying to windmills an apparatus or contrivance which shall cause the vanes, constructed or formed in a new and peculiar manner, to regulate themselves, so as to preserve an uniform velocity under those circumstances in which the wind would otherwise irregularly impel them, as is the case with the sails or vanes of mills of the present construction. I accomplish this object by forming the vanes (for the sake of lightness) with fewer cross bars or shrouds than in the common method, and filling up the remaining open space with small flat surfaces, formed either of boards or sheet iron painted, or any other fit substance, (though I prefer and recommend them to be made of a framing of wood, covered over with canvass.) I hang or suspend the same on their ends by gudgeons, pivots, centres, or any other convenient method, so as to open and shut like valves, (for which reason I shall hereafter so call them,) preferring always to have the centre of motion as near the upper longitudinal edge of the valve as possible, as shown in the drawing, bb, fig. 141, which exhibits a valve detached. I apply these valves to vanes of the present construction, by suspending them to the cross bars or shrouds of the vane by their longitudinal edges, fastened thereto by joints or otherwise, as may be preferred. These vanes, constructed of valves as above described, and which are represented in the drawing, fig. 142, present a greater or less surface to the wind, according as it acts with more or less force on them; and if the wind be

very

strong or high, the valves, by its impulse, would turn their edges to it, and their surfaces parallel to the direction of the wind; the vanes would consequently remain stationary, or at least have but little motion; but to obviate this circumstance taking place, I apply an apparatus which shall cause the valves always to present their flat surfaces to the wind, or such portion of their surfaces as may be desirable. The apparatus which I have usually applied is exhibited in the drawings, figs. 143 and 144, which last figure shows two modes of performing this object; though it must be evident that various other means may be applied to produce the same effect on the valves, and I therefore do not mean to confine myself to those precise modes of effecting it, but consider it unnecessary here to detail others, as the examples exhibited in the drawings fully ascertain the sort of apparatus requisite. "Fig. 142 represents a set of vanes, in which A A show the valves turned to the wind, and their surfaces all exposed at right angles with the direction of the wind; B B exhibit the vanes as close reefed, or the valves with their edges to the wind, so that it can have no effect upon them except on their edges, which must be trifling. In the drawing, the vanes are exhibited as having the whip down the middle, with valves on both sides; but it is evident that the vanes may be constructed with the whip placed in the usual way, and have valves on one side only, which is the method I usually adopt in applying them to vanes of the present form.

"Fig. 143 represents a side view of the apparatus for regulating the valves; and fig. 144 is a section of the same, exhibiting two methods of performing this operation. A represents the shaft, which is bored through its centre to admit an iron rod B to pass freely through it; one end of this rod is made to turn in a box C, which is fastened to a toothed rack D, whose teeth take into those of a pinion E, upon the axis of which is a sheave F, with a groove on its circumference to receive a rope G, to which is hung a weight, shown at H, fig. 143, and which must be sufficient to regulate the force of the wind upon the valves, though no precise quantity of weight can be herein specified, as the same must be adjusted by experiment, or by the quantity of work to be performed by the mill. On the top of the rack D is a roller I, which serves to keep the rack and pinion in the proper depth of geer. The end of the rod B, which turns in the box C, has a knob or onion on it, by which it can be moved endwise while it is turning in the box C. In the other end of the rod is fixed a boss or plate of iron K, with a gudgeon projecting from each side, on which are the bridles or leaders LL, which permit the levers M M to describe a curve with their ends while the iron rod B moves in a straight line. NN are two studs or props fixed to the stock O of the sail; on the ends of which props the levers M M move, and communicate their motion to the racks PP, the teeth of which take into the pinions QQ, on the axis of which, (according to one method herein exhibited, fig. 145,) is fixed a strong iron stud R, which is attached to a rack or slider S. Iron studs or levers are fixed at one end in this slider S by a pin or gudgeon, and at the other made fast to the valves a, which move on gudgeons as before described.

"The other method of regulating the valves is shown at