The annexed figures are views of an improvement in the construction of iron, stairs, I invented by Benjamin F. Miller, of this city, I (N. Y,) and which was patented October, 1849. The improvement consists in making u*e of a series of, stationary bent levers made of iron bars, to form a stair. Out of a bar of iron is formed the baluster, a d, (figure 1) the rise, d e, and tread, c A portion of the bar is bent to form the tread at right angles to the part which is to- form the rise and baluster. The upper end of the bar is furnished with a tennon, a, to fit into the rail, and there is a tennon on the other end to be inserted into the hole in the rise of the preceding bar. The stairs, as constructed, consist of a series of these bent iron levers, attached to one another, and retained in their stationary and upright position as shown in figure 2 by the rail, E. The rail acts upon the long arm, 1 2, of the lever or bar, and thus braces the whole series firmly together. When a lighter rail and additional strength is required, a brace, B', figure 2 is employed. It is either made in sections, or is continuous and is riveted to the shorter arm, 1 3, of the lever at the apex of the angle. To construct a stair of cast-iron on this principle the baluster, rise, head, and underbrace, are made in one piece as shown in figure 3. It has a lug at i, to which the end of the next tread is riveted, and the end J of the under brace, B, projects to receive and be riveted to the brace of the next baluster, rise, and tread, and so on in succession. On the inner side of the tread, C, there is a ledge cast to receive the plank for forming the step; the projection, 5, in front of the baluster, E D, forms a finish to the front of the step. Figure 2 shows how the rail, E, keeps the levers in position, and figure 4 shows the position the stairs would assume if the rail was removed, and the rivetings, 4 5 6 7, yielded to a weight upon the treads. It is therefore plain, that so long as the rails prevent the balusters from changing their upright position, the stair will resist incumbent pressure when supported at its extremities, A B. In figure 5 the under brace produces a similar effect with this difference, the rail acts more powerfully on the long arm, A B. of the levers, while the brace, C D, acts on the short arms. Stairs constructed on this plan can be made in sections at the workshop, and transported to any place, and will then require only to be set up, which can be done by any handy person. By making the baluster, rise, and tread a lever, an increase of strength, with a diminution of material is ob-I tained over stairs made in the common man-[ ner. These stairs cost very little more than I wooden ones. The steps can be renewed I when worn out without removing the railing. : The stairs can be made ornamental as well as plain. A flight of ten steps built on this principle, weighing only 57 lbs., is in use in I a dwelling house in this city, and has been tested with 1,500 lbs. Stairs on this princi-I pie have been in use in this city for two years. i More information may be obtained by calling ; or by letter addressed to the patentee at No.[74 Trinity Place, N. Y