In the manufacture of iron, by the Blast Furnace, it is of the utmost importance that the pressure of the blast should be as nearly uniform as practicable, lor which purpose an improved apparatus has been invented by Geo. Race, of North East, Duchess Co., N. Y., who has taken measure to secure a patent. It con-sis*s of a hollow metal valve, shaped like a box, and fitting loosely in a tubular socket ol the same form as the blast pipe, but much smaller. The pressure of the blast upon the valve is regulated by a spriag, and according to the degree of pressure it'opens or shuts bj a corresponding movement, two passages on the opposite sides of the socket. These latter are furnished with shutters or plates, working on a pivot, which are acted upon by the valve, and, according to the position in which they are moved, regulate the entrance of the hot blast into the tuyeres. In order that the quantity of air passing through may correspond inversely with the density, the area of the passages can be varied by adjusting the plates to a proportionate width and the working pressure may likewise be increased or diminished at pleasure, by means of a screwed rod connecting the valve and spring, and which serves to regulate the tension of the latter.