on each side of the outer frame II, is a support of wood or iron K K, and runs from the axle of the preceding sail (on which it turns) to the upper part of the succeeding frame I I, playing on a pin. These are supports to the frames against the power of the wind, and which, by playing top and bottom, allow the sails to turn round the drums at each end; at the upper ends of each outer frame is fixed a sheave or pulley M M, over which passes a rope, this rope is fastened to each upper corner of the inner frame or sail at one end, and at the other end it has a spring N N, which spring has two small grooved wheels running in a channel: this channel is contracted more at the upper than lower end, so as to produce whatever resistance you wish the sails to make against the wind. These springs N N regulate the sails, so that when they receive too great an impulse, they pull the springs on each side and the sails recline, letting the extra power fly off, as shewn in Fig. 2.

The body of the mill may be of various shapes and dimensions, as described by the dotted lines O and P. Where much room is wanted for a manufactory, it may form a circle as P; and also as represented in Fig. 3, where it is shewn placed over a fixed storehouse Q, on which the head turns at SS; but where little machinery is wanted or no manufactory, as in mills for drainage, &c. it must have its length, but there is no necessity for its being near so wide, as shewn by the dotted line O, though the base must be sufficiently extended to make it safe against the wind.

The head A A may travel round on wheels and in a channel, and being placed to such an angle of the wind as where the sails act to the greatest advantage, (the under sails being sheltered from the wind and the upper

ones

ones receiving it in an angle between each other) they pull round the drum-wheels BB by their extremities,, to the shaft of which is fixed or coupled the manufac turing machinery, &c.

The width of the sails, and the distances from each other, must be so regulated as that the wind may strike the sails sufficiently at the same time, not to make the angle of the line of sails with the wind too great.

Only eight sails are here represented in action, but the number is not limited; the power may be carried, much farther by increasing the distance from drum to drum and adding sails in proportion; and adding length, to the sails increases the power in proportion to the increase of sail, without losing time, which is not the case in the present vertical mills. The sails must be made full to form a concave surface to the wind.

Fig. 2 shews a sail borne down in part by the extra force of the wind. EE the axle and wheels. I the outer frame. JJ the inner frame and sail. NN the spring, rope, and guide. KK the supports to the frame I I. F the chains.

Fig. 3 represents a mill formed circular and placed over a fixed storehouse. Q the store. A A the head."

SS where it turns. JJ the sails.

Fig. 4 shews the spring and guide in large. The machinery for a floating tide or current mill of great power, I forin similar to the preceding one for wind therefore the same drawing will serve to refer to, only allowing the lower sails in Fig. 1 to represent the floats of this, and the water to flow from X to Y, towards which they act. These floats may be of wrought-iron or other materials, and will in general be broader than deep, though, as in the wind-mill, must form a concave VOL. XVIII.SECOND SERIES.

D

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surface to the current, which if running only one way, the concave side of the float may be so fixed; but as by tides, where it operates both ways, it is made to turn on a pivot in the centre, above and below, of the frame, as shewn in Fig 5. A is the frame. BB the floats. CC the pivots on which it turns, and when its concave side is placed to the current, it is fastened on each side at DD; but to shew the disposition of the floats and works in action, see Fig. 6, which represents two boats E É, that must be connected together by proper framing, &c. which framing may pass between the upper and lower line of floats.

The boats are placed parallel with the current F F F F, and between them is fixed on a proper angle with the current the floats and machinery G. Here 121 floats are constantly acted upon by the current: though in this as in the wind-mill the number is not limited; the longer are the boats the longer will be the line of floats, and the power is increased in proportion. It is to be ob served that the floats should always be made as deep as the current will admit of, for in this as in the wind-mill you gain power without losing time.

The drum-wheels, chains, and axles and wheels, are the same as for the wind-mill; but as water is a steadier power than wind, the springs are not required to this, and are omitted in the drawing for the lower sails.

Fig. 7 represents the improved machinery for a watermill, or a mill so called, as receiving its power from a fall of water.

A the upper water, and flowing out at B. C the lower or back water. D are two or more metal wheels through which passes a shaft. These wheels have on them cogs or stumps E, shewn also in Fig. 8, at regu

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