An improvement in the above has been in-vented by John Griffith, of Philadelphia, Pa. The valve cock possesses advantages overthe plug cock in its lightness, and, the facility with which the valve is ground tight ;o as at present constructed, it is frequently in practice very imperfect. It is usual to make the scr*w, by which the valve is opened and closed on the valve stem, and unless every part is very perfectly constructed, this will cause one side oi the valve to close sooner or bear in its seat harder than the other parts, which will be liable to bend the stem, and this difficulty is attended with worse consequences when the valve has a broad bearing. The object of this invention is to provide a remedy for the above difficulties, by making the valve with a cylindrical stem, passing through a, hollow stem, which forms part of the body of the cock, and is furnished outside with a screw, to which is fitted a nut. This nut carries a yoke, in which the valve stem is capable of turning freely but not of moving longitudinally. By turning the nut the valve is raised and lowered from and to its seat, in a right line; the valve being avays kept in such a position that itwill fall truly into its seat and close perfectly when the valve stem is turned. The inventor has taken measures to secure his invention by patent.