THE CIRCULAR SAW. 



24; 



The Circular Saw. 



In one sense the Cordon Saw is a Circular Saw, but we now 

 restrict the name to the tool which has a circular blade, more 

 or less deeply toothed on the edge. The largest and coarsest 

 of these saws are of enormous diameter, have teeth several 

 inches in length, and can cut a large tree-trunk asunder in a 

 wonderfully short time. 



There is a huge saw of this kind in Chatham Dockyard. 

 It is kept in a sort of cellar covered with flap doors, where it 

 really has the air of some dread monster lying in wait for prey. 

 A tree-trunk is brought for it to feed upon. The doors slowly 

 open, the saw emerges, revolves so fast that the eye cannot 

 detect the teeth, seizes on the tree- trunk, tears its way through 



SAWYER-BEETLE. 



CIRCULAR SAW. 



with a scream and roar, and then sinks back into its cellar. 

 I have often watched this saw in action, and have never been 

 able to get over a kind of feeling that it was alive. 



Now, if we suppose the saw to be pierced in the centre, and 

 to have teeth on the inside instead of the outside, it would be 

 equally efficacious ; and, indeed, we have several tools used for 

 cutting iron bars or pipes, that are constructed on a similar 

 principle, though the cutting tooth revolves slowly instead of 

 rapidly, and is urged by a lever handle. 



There is in Nature a Circular Saw of just such a character, 

 the teeth having their points directed inwards, and not out- 

 wards. 



