stop a corresponding aperture or seat formed in the passage through which the liquor is intended to flow when it is drawn off. The plug is to be pressed down into the aperture of its seat, by means of a screw formed on the upper part of the stem of its spindle, which works in a corresponding hollow screw formed in the head part of the cock. When the plug is turned so as to screw it down to its seat, the passage of the liquor is stopped, but, on turning it back again, the screw raises the plug, and opens the passage for the flow of the liquor. This is a common construction, and it is upon this kind of cock that the present improvements are founded. In the ordinary cocks of the description above mentioned, in order that the screw and internal plug or valve may be turned round by means of an external handle or key, the upper end of the spindle of the plug or valve (on the lower part of which the screw is formed) is made to pass through the top part of the cock, and a collar of leather or other flexible material is placed in the, seat of the valve, to render the plug tight when shut down. But the liquor is very liable to leak between the stuffing and the seat of the plug, and also at the stem of the spindle, which the present invention is intended to prevent. The Patentees say, "Our improvement consists in applying the action and force of the external turning handle, by means of which the internal plug or valve and its screw are to be turned round, in order to raise the plug or valve out of its seat, or else to press the same down into the seat, by means of a connection with the lower end of a small stem or spindle, which projects downwards from beneath the plug or valve, and passes through the centre of the aperture of the seat; the external turning handle and its connection with the lower stem of the plug or valve, being constructed in the manner represented in the drawing. See Plate XI. figs. 7, 8, and 9. 66 By virtue of our improvement, the communication of the necessary motion from the external turning handle to the internal plug or valve, and its screw, being made by means of a stem which descends from the lower side of the plug or valve, and beneath and beyond the seat into which the same is fitted, instead of making the said communication by means of a prolongation of that stem, which ascends from the upper side of the plug or valve, above the seat, no stuffing or collar of leather is required round the stem, whereby we communicate the turning motion to the plug or valve from the outside turning handle; and consequently if the plug or valve fits tightly into its seat, there is no junction of moveable and fixed parts at which the liquor can leak or escape from that part of the passage which is above the seat. Fig. 7, is an external of the improved cock; fig. 8, is a section of the same, shewing its internal construction, the plug being screwed down, and the passage of the liquor closed. Fig. 9, is a similar section, the plug being raised, and consequently the passage open, as in drawing off the liquor; a, is the tube through which the liquor passes from the barrel, or other vessel in which the cock may be fixed, or from a pipe to which it may be attached; b, is the orifice or spout through which the liquor is discharged or drawn off; c, the conical plug or moveable valve; d, is the chamber of the cock, in which the plug acts; e, the seat for the conical plug to rest in; ƒ, the stem, with the screw on its upper part, having sharp or oblique threads of seven or eight spirals; g, the hollow screw or recess into which the stem passes when the plug is raised. The seat e, e, is formed of a distinct piece of metal from the body of the cock, and is attached thereto by a screw cut round it, having a collar of leather to keep it watertight. The short central tube h, h, is formed with a cylindrical socket, and turns freely on the outside of the part e, e, by means of the handle i. Across the lower part of the stem f, there is a key piece, for the purpose of locking the stem to the tube h, into two perpendicular grooves, of which the key passes. When the tube h, is turned round by means of the key i, the stem goes round with it, and by so doing causes the screw at the top of the stem to draw the plug up, and to open the passage. Turning the handle the reverse way, of course brings the plug down again, and stops the aperture. The rise or obliquity of the threads on the stem, must be such, that by turning the handle about one fourth, the valve will be completely raised, and the passage for the discharge of the liquor opened. The socket k, which turns on the outside of e, is attached thereto by studs screwed from the outside, which pass into small grooves, and keep the tube from falling off.-[Inrolled in the Petty Bag Office, February, 1829.] [In the first volume of our present series will be found the specification of Mr. Gossages patent for improvements in corks for drawing off liquors, on comparing which with the present specification, considerable similarity of construcrion will be perceived. It may therefore be needful to ubserve, that the former invention has, we understand, now become the property of the present Patentee, and of course any approximation to infringement is of no consequence. ED.] ON THE FRICTION AND RESISTANCE OF FLUIDS. BY GEORGE RENNIE, ESQ., V. P. R.S. [Read before the Royal Society, June, 1831.] In the consideration of this question, I propose to examine, first, the retardations of the surfaces of solids moving in fluids at rest; secondly, the retardations of fluids over solids; and, thirdly, the direct resistance of solids revolving in fluids at rest. To illustrate the first case, I caused an apparatus to be constructed, of which fig. 10, Plate XI, is a representation; it consists of a cylinder of wood ten inches and three quarters in diameter, and twenty-four inches long, and divided into eight sections of three inches in each, and fixed upon a spindle of iron about four feet in length, and one inch and a quarter thick. The apparatus was accurately turned and polished. Upon the upper part of the spindle, a small cylinder or pulley, six inches in diameter was fixed, and a fine flexible silken cord, communicating with the weight, was wound; the apparatus was then fixed in an iron frame, and the frame let into a groove in two upright posts, driven into the bed of the river Thames. The object of the frame was to allow the cylinder to slide up and down with the level of the tide, and immerse it more or less according to the experiment required to be tried. The friction of the apparatus, or the time that the weight took to descend in the atmosphere was first noticed; after which it was successively immersed in the water three, six, nine, twelve, fifteen, eighteen, twenty-one, and twenty-four inches, the difference of time showing the retardation according to the annexed Table. 2 E VOL. VIII-SECOND SERIES. |