406 MEMOIR OF DAXIEL TREADWELL. 



" Having been aware of the fact here stated, and, I trust, in a manner which can be easily 

 understood and appreciated, for many years, I determined, between lour and live years ago, to 

 attempt to apply it, practically, to the fabrication of cannon. My lirst attempt was to make a 

 four-pounder cannon, by the best means then at my command, of rings, or short hollow cylinders 

 joined together end to end by welding. Each ring was made of several thinner rings, placed 

 one over the other and welded. It will be seen, that, in this case, as the bars of which the 

 several rings were formed were curved round the calibre, the direction of the fibres herein shown 

 to be so essential, was fully preserved. I may remark here, that this method was subsequently 

 changed in some degree, by first making a single tiiin ring of steel, and upon the outside of this 

 winding a bar of iron spirally, as a ribbon is wound upon a block. This gun, although imjier- 

 fectly made, withstood the action of enormous charges of powder, and was only burst by using 

 very superior powder, and shot without windage. The fracture was made lengthwise of the gun, 

 or across the fibres of the iron ; and although the welds (technically called jumps), which 

 united the rings to each other endwise, were most imperfect, they yet held together completely 

 against the action of the powder. Two other cannon of similar kind were subsequently made, 

 one of which yet remains uninjured, after having withstood many most severe tests." 



Having this experimental proof of the strength of cannon made in this form, 

 and being satisfied that the principle upon which he wrought is true, he deter- 

 mined to carry it bej-ond the stage of experiment, and, as he hoped, into successful 

 practice. To do this, however, required engines and tools of an elaborate and 

 costly kind, as the large amount of money already spent fully proved, and also 

 some assurance that the guns produced would be adopted by the Government. 



He therefore filed a caveat, in which he gave notice, in a general way, that he 

 had invented and reduced to practice a method of making cannon of wrought iron. 



" But wishing further time to mature and perfect said invention, I hereby in this caveat 

 specify and set forth the design and purpose of my invention with its principal and distinguishing 

 characteristics, that the same may be protected according to law. j\Iy method of making can- 

 non or great guns to ])e mounted by their trunnions upou«carriages is as follows. First, I 

 form rings or hollow cylinders of wrought iron by bending bars of iron around a proper mandrel 

 of the i-equired size, and welding their ends together liy a scarfed joint. These rings are to be 

 of the thickness required for the walls of the cannon at the part where they shall be placed, 

 and of such length as shall be most convenient to handle and work, — say about equal to their 

 diameters. Having made such numbers of rings as when placed end to end shall be equal to the 

 length of the cannon required, I weld them together endwise so that they form one cylinder, 

 which with the trunnions and other appendages shall constitute the cannon. . . . Again, in 

 forming the rings of many thicknesses, instead of forming complete rings, as before described, 

 the iron may be wound upon itself after the manner of winding a ribbon upon a block." 



The remainder of the caveat describes several ways in which the iron may be 

 arranged, and some general directions as to the manufacture. It is dated at Boston, 

 June 19, 1841. 



To obtain the assurance of Government aid, Professor Treadwell, in March, 1842, 

 went to Washington. 



