The annexed engravings are views of an improvement for welding iron tubes, by J. Clark and C. Robinson, of Birmingham, Eng., and which they have secured by patent in that country. Figure 1 is a sectional elevation of rollers for forming, welding, and drawing tubes ; ngure a JS a VIG US Wkw .......A. *.i ___*T---,), with the bulb upon it ; figure 3 is the section of a manufactured tube. The skelps, B, of iron plate, for forming the tubes, are ot equal thickness throughout, the same as are used in manufacturing tubes in the ordinary manner ; these skelps, after being brought to a welding heat, are submitted to a pair of rollers, A A, of the usual construction, set in suitable frames, C. These rollers at once, while the skelp is at a welding heat, turn over the sides of the skelps, and bring the edges in contact, and then weld them. This operation is effected upon the bulb, D', of the mandrel, D, over which the newly-tormed tube, B', ia drawn towards the other end of the mandrel, the length of the skelp being dependent upon the length of the tube to be manufactured.— The tube thus lormed is, however, notwithstanding the taper form of the mandrel, cylindrical in shape and equal in substance throughout, the interior diameter being equal to the diameter of the bulb, which will be about onal to the ereatest diameter of the mandrel. The outer end of the mandrel, D, is supported and held by the standard, E, abutting against the stop, thereon, thereby maintaining the bulb, D', at the other end of the mandrel, in its proper position between the rollers, A A. When the whole of the skelp is passed through the rollers and the tube passed over the mandrel, the stop, F, is lowered, and the tube (with the mandrel within it, but the j bulb at the end removed) passed on to another pair of rollers, similar to the last, between which the tube is drawn. These rollers have somewhat smaller grooves upon their peripheries, and thereby reduce the thickness of the tube at the end where the thickest end of the mandrel is situated, and roll the superabundant metal therefrom to-; wards the other end, where the metal thick-I ens, thus forming the tube of cylindrical ex-: terior, but gradually taper within, conforming to the shape of the mandrel. Should the I tube now be found to be sufficiently formed, I both exteriorly und interiorly, and of the proper thickness required, it is passed to the draw-bench, for the purpose of extracting the mandrel ; but should it not be considered properly finished and smooth, it may be again passed through another similar pair ot rollers for further reducing it and completing it.— The draw-bench employed is of the usual construction ; and should there be any difficulty in removing the mandrel from the tube, re-heat the tube, and then submit it to the action of the draw-bench, or by means of cold rolling the tube between three rollers, as is well known, and thereby loosening it upon the mandrel. The object of making the tubes conical for steam boilers is to make them stand the unequal tear and wear of fire exposure. The ends of them nearest the fire being subjected to greater heat, and, consequently, wearing away faster than the ends more remote therefrom, in the case of the use of tubes of the usual construction, namely, when they are cylindrical and parallel from end to end, and the tubes ol equal thickness throughout, the result is, that when the end nearest the fire is worn out and rendered unfit, the other end will still be in good condition, and might, if dependent on itself, be still used without removal j but it will, in consequence of the worn-out condition of the one end, be necessary to remove the whole tube ; it is intended by the present invention to remove this inconvenience and disadvantage, by the employment of tubes so made and constructed that the part of the tube m ost subjected to the wear and tear shall be in better condition to resist it, and cause the tube throughout its whole length to be BO affected by the wear and tear as to be worn out or rendered unfit for further service, equally. This the paten-tentees effect by increasing the thickness of the substance of the tubes at the parts most exposed and subject to the wear and tear, and, at the same time, reducing in thickness the parts less exposed—in fact, forming them of a gradual taper upon their interior, while their exterior still remains cylindrical, and of the same diameter as when constructed as usual ; by this mode of construction, the tubes will be worn out or rendered unfit for further use equally. Although this mode of forming the tubes renders them capable of sustaining a* greater degree of wear and tear, lasting longer, and consequently being more economical. It is not attended by any increase of weight of the whole of the tube, as the quantity ot the metal necessary to increase the thickness of the one part of the tufi will be obtained from the other part, by Mftiifduction of the thickness there. A hundred mill gtraifillacteti fey an American speculator in Glasgow, have sailed from the Clyde, to commence a new cotton mill at New York. The party sailed in the Mary Morris trom Greenock. News here. Literary Notice BOOK OF THE WORLD—No. 7 ; Weik & Wieck, 195 Chesnut st, Philadelphia, ia an encyclopedia of choice literature and knowledge, it contains many thrilling and instructive historic tales, with sketch-en of philosophy and natural history of the most interesting and useful character. ORNAHIKTAL DRAWIKO, FOR PAINTERS, SOULP-TOBS,CARTKRS, ARCHITECTS, 4C, by Sullien, Bilor-deaux, Kotterruan, Metzger, and other, publithed at the same place as the above, In one of the most beautiful publications we have lately met with, the designs are chaste and elegant, as well as bold and ornamental ; the work is executed in a very superior style, and deserves an extensive patronage No. 3, 4, anrm 4re received. Putnam's Monthly for May, No. 5, continues as entertaining as ever, it opens with a posthumous publication from the pen of Oooper, the uovellet, being the naval biography of the frigate Constitution, familiarly known aa " Old Ironsides " This vefsel was one of the six ships that formed the early marine of ourcountry, and was commanded at different times by some of our most celebrated sea captains. A perusal of this lant writing of such a celebrated man as J. Fennimore Cooper, is interesting for many reasons. The other articles are all wtU written. Success to Putnam's Monthly
This article was originally published with the title "Welding Conical Iron Tubes"