The apparatus consists essentially of two tempered iron cylinders, A, 0.5 of a meter in diameter by 1.5 meters in length, revolving in the _same direction_ (contrary to what takes place in ordinary rolling mills) between two frames, B, that are open on one side to allow of the entrance of the finishing bar. This latter is held between the cylinders, A, which roll it so much the faster in proportion as its diameter is smaller, and by a scraper guide, C, of the same length as the cylinder table, and which may be regulated at will by bolts, c, fixed to the frame, B. The bottom cylinder remains always in the same position, while the axle, D, which carries the intermediate wheels, E, moves about to gear in all the relative positions of the cylinders. The displacement of the upper cylinder is effected through the clamping screws, b, which are actuated by toothed disks that gear with two endless screws keyed at the extremities of one shaft in common, d, which is set in motion by hand through the winches, m m. The scraper guards, e e, take up and throw aside all scales that might become attached to the cylinders, which are constantly moistened by small streams of water coming from an ordinary conduit. [Illustration: CHUWAB'S DRESSING AND ROUNDING ROLLING MILL. Fig. 1--Elevation and Longitudinal Section. Fig. 2--Side View. Fig. 3--Transvers Section. Fig. 4--Plan View. Figs. 5 & 6--Saws for Dressing the Extremities of the Bars. Fig. 7--Diagram Showing the Motion of the Wheels and Guide. Figs. 8 & 9--Apparatus for Shifting tha Bars.] As the driving belts are mounted on pulleys, G, of a diameter proportioned to the velocity of the shafting, the iron pinions, h, in order to produce 60 revolutions per minute in the first shaft, H, gear on each side with the intermediate wheels, E, and these actuate the two bronze pinions, a a, that are mounted on the extremities of the cylinders, A A. The axle, D, of the intermediate wheels does not revolve with them, but is capable of rising and descending in the elongated aperture that traverses the frames, B. The displacement of this axle is secured through the arms, L L, whose extremities articulate on the one hand with the cylinders, A A, and on the other with D. The result of this is that every displacement upward of the top cylinder corresponds to a different position of the intermediate shaft, and one that is always equidistant from the centers of the cylinders, A A, thus securing a constant gearing of the wheels in all the positions of the cylinders, A A. The diagram in Fig. 7 shows the relative displacements of all these parts, as well as those of the scraper guide, C. The diameter to be obtained is determined beforehand by the two contact screws, P.