Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 2, 1802).djvu/314

484] FIR wheels or cylinders of brass, or any other metal j one of which is of a greater, and the other of a smaller diameter, in any proportion re- quired ; both are nearly of equal length, but may be increased or decreased, according to the pur- pose to which the machine is ap- plied. As soon as the larger wheel is fixed, the smaller one is placed within it, and is fastened on an Siis, so as to turn in a rotative direction round its centre ; the smaller wheel being thus stationed, may be occasionally fixed, and the larger one moved in the same direc- tion round the smaller one : the former of these, however, is pre- ferable in all cases. At each end of the larger wheel there is -Ajianck, to which are screwed two p : ates, or caps inclosing its ends, and into which the extremities of the smaller wh el are inserted, so as to render the. junction water-tight : through these caps passes the axis of the inner cylinder, in order to com- municate motion from without. — Or tiie inner wheel may be applied no as to give motion, by its external end or ends, to any other engine or machine connected with it. — These are the component parts of Messrs. Bramah's and Dicken- son's patent engines; for a more particular account of which, we refer the reader to the 2d vol. of the Repertory of Arts and Manu- JaSiures, where he will find a mi- nute account of the machinery, and the effects it is calculated to produce. A patent was likewise granted in Pecember 1/Q'i. to Mr. Charles SiMTKiN, of Oxford-street, en- gine-maker; lor his improvements in all kinds of machines for extin- guishing fire. — -This invention con- sists in exploding or removing the FIR valves both from that part of the cylinder, where the vacuum is made by the piston or fly, and from beneath the air-vessel ; and in making use of valves, by the application of certain filtering chambers, with partitions or divi- sions, to preserve the eflefet of the valves, during the use of any im- proper fluid. These filtering cham- bers are to be placed between the drawing valves, and the strainer in common use, on the suction-pipe. The partitions in the chambers may be of fine wire-work, or of any other substitute, that will act as a first and second filtration in the chamber. The design of this invention is, to render the valves more free of access, and to prevent the neces- sity of opening any other parts of the engine, except the chambers containing the valves ; by which means the effect of the machine is increased, and consequently the. fire may be more easily extin- guished. To these different contrivances we shall add the American Fire- engine, of which we have given an accurate engraving. It was in- vented by Mr. Benjamin Dear- born, who communicated it to the American Academy of Art* and Sciences, from whose Memoirs for 1 704, we extract the following particulars : Description of the Plate represent* ing the American Fire-engine, on a new construction. Fig. 1. A B, and CD, are the edges of two planks, confined to- gether by four bolts. — a b, and c d, are two cylindrical barrels, in each ot which a piston, with a valve, is fastened to tin; spear e, and is mov- ed tip and down alternately by the motiorv