1036
THEORY AND PRACTICE OF ENGINEERING.
Cook II.
changing the position of the strap from the loose to the fixed pulley, which being com-municated to the riveting tool gives the required shape to the rivet.
Eight rivets, ^ inch in diameter, can be firmly fixed by this machine in a minute, bythe assistance only of two men and two boys. In the common process, three men anda boy were required to rivet up forty in an hour ; there is consequently a saving of morethan 10 per cent, in the labour.
A very ingenious machine was made use of for boring the eyes of the main chain links ofthe Alenai bridge; the side elevation and plan sufficiently indicate its form ; the large