MECHANICS AND USEFUL ARTS. , 59 



The exact cost of a single musket, of the number manufactured last 

 year, cannot be stated, the inventory being uncompleted ; but the cost 

 in the year 1850 was $9.03. The cost for the last year will be less. 

 In ten years, the cost of manufacture, per musket, has been reduced 

 nearly one half, it being in 1841, $17.44. 



The process of manufacturing the musket-barrel is one of the most 

 important and difficult in the whole range of the Armory operations, 

 and one which is guarded with multiplied tests, at every step of its 

 progress, from the bar to the finished tube. The bar, which is of the 

 best Salisbury and Ancram iron, is first cut into lengths, weighing 

 10| pounds each. These are rolled into shapes, and then the edges 

 rolled up, lapped upon each other, and welded. They are then in- 

 spected, and the imperfect ones rejected. As they pass along through 

 turning, boring, and grinding, they are subjected to inspection at each 

 step, and the workmen are held responsible for the full value of any 

 barrel they may spoil, at the stage in which it is spoiled, and the 

 amount is deducted from his earnings ; and we say here, that the same 

 course is adopted in regard to every component of the musket. The 

 barrel having been reduced to the dimensions required for proof, (by 

 powder,) which dimensions are three hundredths of an inch greater 

 in the exterior diameter of the barrel, and three hundredths of an inch 

 less in the diameter of the bore, than the finished barrel, leaving an 

 ounce and a half to be worked from each barrel in finishing, it is then 

 subjected to the powder test. Fifty-five barrels are usually loaded and 

 discharged at the same time, in a building made for the purpose. 

 Each barrel is discharged twice, the first consisting of one eighth of a 

 pound of powder, one ball and two wads, each wad occupying three- 

 fourths of an inch of the bore, and each ball one fifteenth of a pound. 

 The second charge consists of one twenty-second of a pound of powder, 

 one ball and two wads, and each charge is well rammed. The barrels 

 are laid on a cast-iron, grooved bed, and the balls are discharged into 

 a bank of clay, which is occasionally washed for the lead it contains. 

 The inspection of the barrels is so rigid before they come to the proof, 

 that very few of them burst. After proof they are again inspected as 

 before, to see that there are no flaws, or cracks, or defects of any kind 

 that will not disappear in the finishing. The number of condemned 

 barrels, in the last year's operations, was, for defective workmanship, 

 451, and for defective material, 5,323. 



In the polishing shop connected with the Armory, an ingenious con- 

 trivance has been recently introduced for sparing the lungs and lives 

 of those who would otherwise live (or die) in a constant atmosphere of 

 emery dust. A long box runs the length of the room, by the side of 

 which are stationed the polishing wheels. Tubes with mouths open- 

 ing upon each wheel proceed from this long box. In the room below 

 a blower is arranged in such connection with the long box as to ex- 

 haust the air within it. and, of course, there is a strong current of air 

 passing from each wheel into its appropriate tube. The consequence 

 is, that ail the dust of the room is drawn into the box, and delivered 

 out of doors in a constant cloud. 



