TRANSACTIONS OP THE SECTIONS. 



161 



From this description it will appear evident that no time is lost ; that 

 no hammering of the rivet takes place after it is cooled, to render if 

 brittle : but the action is completed so rapidly, as to leave it in a per- 

 fectly sound and ductile state. This is a point of the utmost import- 

 ance, as the joint is so firmly united by the subsequent cooling and 

 contraction of the rivets as to render the usual precaution of " caulk- 



ing almost unnecessary. Caulking is an operation universally adopted 

 to prevent leakage, by setting up the edge of the plates upon the seam 

 or jomt with a hammer and a square-ended tool of cast steel. 



By the use of the machine much time and labour is saved, by the 

 substitution of instantaneous compression instead of a long series of 

 impacts. It is applicable to all kinds of circular tubes and boilers, and 

 also to every description of flat and square work. It fixes and cora- 



VOL. VII. 1838. M 



