The press is made entirely of Bessemer steel, and is of the three-column construction, a strong casting of triangular form serving as a base of the press; into this casting the three columns fit, and carry on their upper ends a like casting, forming a top or entablature. Into this top casting the main cylinder is fixed mouth downward, concentric with the machine. Two small cylinders for giving the return or upward stroke rest mouth upward in the bottom casting at opposite sides. The two rams of these cylinders pass through the ends of, and carry, a crosshead, upon which the main ram rests. The two lifting rams are made long enough to pass through holes in the top casting, and thus form guides to the crosshead and mandrel. The main ram is 24 in. in diameter, and has a stroke of 12 ft. The press is worked at a pressure of 3 tons per square inch, giving a down force of 1,300 tons. The two lifting rams are each 8½ in. in diameter, and give an upward force of 300 tons. This large upward force is required for stripping the tubes off the mandrels, in addition to raising the main ram crosshead, etc. Referring to the engraving, the main cylinder is seen at the top with the main ram carrying the crosshead, to which are connected the two lifting rams, the cylinders for which extend below ground. By this arrangement a reciprocating motion is obtained, rams only being used, the central ram giving the downward thrust, and the two smaller side rams giving the upward stroke. Mr. Walker has this press in operation, and from a disk of steel 3 ft. in diameter, having a mean thickness of about 4 in., he has raised a tube or cylinder with a solid end to it 3 ft. 6 in. long and 12 in. in diameter, of a uniform thickness of about 1 in., and sanguine hopes are entertained of producing greater results. Messrs. Bessemer & Co. are now making a larger press of similar construction.--_Engineering._ TIMBER, AND SOME OF ITS DISEASES.[2] By H. MARSHALL WARD. VI. If we turn our attention for a moment to the illustrations in the first article, it will be remembered that our typical log of timber was clothed in a sort of jacket termed the cortex, the outer parts of which constitute what is generally known as the bark. This cortical covering is separated from the wood proper by the cambium, and I pointed out that the cells produced by divisions on the outside of the cambium cylinder are employed to add to the cortex. [2] Continued from SUPPLEMENT, No. 644, page 10281.