MECHANICS AND USEFUL ARTS. 43 



jecting point working in a circular slot in the hammer, which steadies 

 it against the pressure of the lower arm. Thus, the hammer, spring, 

 and lock-plate form the lock. The usual tumbler-screw prolonged 

 holds the hammer upon the lock-plate, and attaches the lock to the 

 stock, the front of the plate being held by the head of a fixed screw. 

 On the outside of the lock-plate is a cylindrical projection, upon which 

 the hammer fits. Through the centre of this the side-screw passes. 

 On the inside of the plate the main-spring is attached, about the centre 

 of its length, by a pin, and its lower arm bears upon a fixed stop on 

 the plate to stiffen it. The exterior surface of the hammer is as at 

 present ; on its inner face is a circular projection, centring with the 

 cylinder on which the hammer turns, and revolving in a bed in the 

 lock-plate, of a depth equal to half the thickness of the plate. Near 

 the outer edge of this projection is screwed permanently the piece act- 

 ing as sear, which works in the notches on the end of the main- 

 spring through a hole in the lock-plate. A groove in another part of 

 the projection allows the projecting point on the end of the upper arm 

 of the spring to work in it, passing through a cut in the lock-plate 

 also. These two cuts in the plate are covered by the hammer. The 

 hammer can be taken off when drawn to its full height, without the 

 use of a spring-vice, thus effecting another economy in dispensing with 

 this. With the hammer off, the lock can be thoroughly cleaned. 

 This suggestion, due to an apprentice boy at. St. Etienne, seems to me 

 to have many merits to commend its introduction. 



" An ingenious lock for small arms has been made at Delft, and is 

 said to have been fired more than one thousand times without a failure. 

 The lock consists of but one piece, a spring (acting also as the 

 hammer) ; the cone is in the axis of the gun, on the breech-pin ; the 

 trigger forms part of the spring. One end of the spring rests in a 

 notch forged under the barrel ; by pressing down the other end, the 

 trigger-notch catches on the guard-plate ; by pulling back the trigger, 

 the spring is released and the cap fired." 



Major Hagner also mentions that in the French armories it is the cus- 

 tom to repair defective gun-barrels by piecing them. This is done at 

 all stages of the fabrication, even in cases where barrels burst in proof. 

 He thinks this plan worthy of adoption, to some extent, in this country. 



PERCUSSION-CAP MACHINES. Major Hagner mentions a machine 

 for making percussion-caps, which he says promises to work well. 

 " The copper, in strips, enters the machine vertically, being fed in, by 

 rack, at each end of a lever-arm, to dies, cutting the star and forming 

 the cap (as with us), the cutters attached to the ends of a swinging 

 baara, moved by an eccentric, so that a star is cut and cap made alter- 

 nately at each end of the beam, or one every half revolution of the 

 crank. The punches act horizontally, and a piston pushes the finished 

 cap from one matrix as the punch enters to form the cap in the other. 

 This secures, as with us, a freedom from clogging. The inventor 

 had conceived and partly matured a plan for combining the filling and 

 varnishing operations with this machine, the only instance that I saw 

 in Europe where the idea of such a combination seemed to have been 

 entertained at all." President's Message, Part I. 



