This Mill produces a double power, merely because it uses two pair of sweeps or sails, both of which (though turning opposite ways) concur in giving the same motion to the vertical shaft of the mill. A B [fig. 5], ([Plate 38]) is the shaft in question. It has on it two bevil wheels or pinions o, b; bearing the same proportion to their respective wheels: one of which (o) works in the wheel C, fixed to the outer shaft a c, and the other (b) in the second wheel D, which takes it’s motion from the inner shaft E D. This latter, then, is turned by the front sweeps F G; which revolve, as usual, “against the sun,” while the other sweeps H I, are braced round the large shaft a c, and turn with the sun—being sloped and clothed for that purpose. Now, lest any doubt should arise, whether these two sets of sails would not injure each other’s motion—I would remark, that one principal effect of the front sail on the wind would only be to turn it aside, and thus make it the more fit to turn the other sails, which require to go the other way; and which, therefore, will rather be favoured than otherwise, by the aforesaid effect on the direction of the airy current. It may be useful to observe, that the two sets of arms can be put, circularly, into any given position, by means of the wheels C D, and will retain that position if the proportions of the wheels to the pinions o b, are the same for each pair—a result which it is easy to insure.
I shall dwell no longer on this subject, convinced as I am that nobody will question the propriety of enlarging the scope of these operations. It is a subject I especially recommend to our Batavian neighbours—the more, as, without presuming to dictate on a subject they may think I have not experience enough to judge of—I have only a hint to give to their Moolen Maakers, to insure their attention to a subject so intimately connected with the welfare of their never-forgotten Vaderland.
OF
A WATCH ENGINE,
To extinguish incipient Fires.
It is well known, that many ruinous fires have originated so slowly, that they might have been put out in a minute, had a little water been at hand—especially with the power of throwing it to a short distance. This fact makes it more desirable than it would at first appear, to have small vessels full of water, furnished, in themselves, with the power of forming a jet, without a moment’s delay! and this is the purpose of the Watch Engine, represented in [fig. 6] of [Plate 39].
In that figure, A B is a cylindrical vessel, with spherical ends, made strong enough to bear (without danger) a pressure of several atmospheres: and into which is introduced, by a condenser, (which might be the very system C p r) a quantity of water sufficient to occasion the aforesaid pressure. The valve C being water-tight, retains entirely this water; and the Machine is placed on it’s three feet, in a corner of the apartment it is wished to secure. It is seen in the figure, that the valve-pipe C p, opens into the ejection pipe p q, while the valve stem p passes through a collar of leather, and comes in contact with the lever p R while in it’s present position. If, now, any part of the house or apartment should be found to be on fire, this Instrument can be carried there instantaneously, by the pipe p q, as a handle; and the jet be levelled at the point desired: when, by taking the lever p R in his hand, with the pipe p q, the bearer will open the valve C, and thus have an immediate supply of water, in a state of impulse sufficient to quell a fire that might else have become so violent as to mock every attempt to extinguish it! This, then, is the object of the present simple tribute to public safety.