406 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



the magnetism is gone the moment the magnet is removed ; so 

 that it will attract the north pole or the south pole equally. 



Mr. Churchill considered crystallization as the best test for the 

 mechanical homogenity of steel. Cast iron, with small granules, 

 may be stronger than a purer iron in which the crystals are 

 larger. If we chill cemented iron we produce a rapid condensa- 

 tion, which is just the condition in which small crystals are pro- 

 duced. We have three conditions : want of fluidity, want of 

 rest, and want of time, each conducing to the production of small 

 crystals, and each coincident with the greatest strength in differ- 

 ent irons. 



Mr. Harrison, from Massachusetts, inquired about the "Damas- 

 cus steel." He had observed about it the peculiarity that if it 

 is heated too highly, instead of being burned like the English 

 steel, it will still make a pretty good tool. This steel seems to 

 be flaw^ey, and there will be fire cracks in hardening it. 



Mr. Stuart seated that Mr. Wiard had met with remarkable 

 success in making cannon from puddled and cast steel. 



Mr. Wiard, in response to questions, stated that the gun 

 referred to weighed, when finished, 700 lbs. The bore -is 26 

 inches, and the length 18 diameters, or nearly four feet. He 

 considered the puddled steel guns the strongest. 1'he machine 

 for rifling he explained by a drawing. The tool commences at 

 the bottom of the bore and moves forward, drawing out a shaving 

 ■which sometimes comes out in one piece, and may be drawai oiit 

 like a watch spring. The twist commences at nothing, and ends 

 with one revolution to nine feet. He explained his process for 

 forging the steel : taking a square bar, five inches square, sur- 

 rounding it with slats converting it into a longer octagon, and 

 surrounding this with others converting it into a circle. A square 

 bar of steel cannot be hammered into a round form without mak- 

 ing flaws in the center; but by this method the form of the cen- 

 tral bar is unchanged in the forging, and after the gun is finished 

 the square is plainly visible at the end. The hole is drilled 

 before the forgiiig is completed, and the inside is then kept cool 

 by a syphon pipe while the outside is hammered. Mr. W. also 

 -described an improved gun carriage, allowing a ranga of eleva- 

 tion from 35 deg. to a depression of 30 deg., instead of 14 deg. 

 as now used in the service, and also preventing the aim from 

 being injured by the recoil excavating the earth behind the 

 piece. He also described an improved wheel, in which wedges, 



