PROCEEEDINGS OF THE POLYTECHNIC ASSOCIATION. 459 



standing in the center of the square, furnisli the only outward and visible 

 show of the military character of this immense establishment. 



The water-shops formerly occupied three diflerent sites, being denomin- 

 ated the upper, middle, and lower water-shops, on a stream called Mill 

 river, which exhibits, in a distance of less than half a mile, four or five of 

 the most charming waterfalls to be seen in the State. In 1817 these works 

 comprised five work-shops, twenty-eight forges, ten trip-hammers, eighteen 

 water-wheels, nine coal-houses, three stores, and five dwellings. These 

 buildings were all constructed in the most substantial manner, of stone and 

 brick, and yet remain in an excellent state of preservation. The trouble 

 and expense attending the transportation of the various parts of the musket 

 from one series of shops to another, however, rendered it desirable to 

 assemble them all in one place, and the location of the upper shops was 

 decided upon as the nsost advantageous. About eight years ago the work 

 of constructing the new shops was begun. Extensive excavations were 

 made for a new dam, the bed of the stream was changed, the sides being 

 laid for a distance of half a mile with freestone, and the basin raised five 

 feet above its former level. Some idea of the magnitude of these works 

 may be formed from the fact that over one million dollars was expended 

 upon the foundations alone, before a brick was laid in the superstructure. 



The first operation is the formation of the barrel. Formerly these were 

 made from the plates of iron called scalps, about two feet long and three 

 inches wide, which were heated to a wi)ite-heat and then rolled up over an 

 iron rod, and the edges being lapped were welded together, so as to form 

 a tube of the requisite dimensions, — the solid rod serving to preserve the 

 cavity within of the proper form. This welding was performed by tilt- 

 hammers, which were carried by the water-wheels. Underneath the ham- 

 mer was an anvil containing a die, the upper surface of which, as well as the 

 under surface of a similar die inserted in the hammer, formed a semicylin- 

 drical groove, producing, when the two surfaces came together, a complete 

 cylindrical cavity of the proper size to receive the barrel to be forged. 

 The workman, after heating a small portion of the barrel in his forge, 

 placed it in its bed upon the anvil, and set his hammer in motion, turning 

 the barrel round and round continually under the blows. Only a small 

 portion of the seam is closed by this process at one heat, eleven being 

 required to complete the work. To eft'ect by this operation a perfect junc- 

 tion of the iron, so that it should be continuous and homogeneous through- 

 out, without the least flaw, seam, or crevice, required unremitting atten- 

 tion, as well as great experience and skill. The welders formerly received 

 twelve cents for each ban-el welded by them, but if, in proving the barrels, 

 any of them burst, through the fault of the welders, they were charged 

 one dollar for each barrel which failed to stand the test. This method has 

 now, however, been abandoned, and a much more economical and rapid 

 process adopted in its place. Instead of plates of two feet in length, those 

 of one foot are now used. These are bent around an iron rod as before; 

 but in place of the anvil and tilt-hammer, they are run through rolling- 

 machines, analogous in some respects to those by which the railway-iron 

 is made. The scalps are first heated, in the blaze of a bituminous coal 



