FOREST SAW-MILLS. 



679 



communicates the motion through the cog-wheels M, L, k, and 

 thus pushes forward the butt-carriage and the butt against the 

 saw. At the downward motion of the saw-frame, the ratchet q 



Fia. 301. 



is drawn backwards, catching a cog in N when the saw is at 

 its greatest height and again forcing N round at the next down 

 stroke of the saw. U is the water-wheel which drives the saw, 

 the small water-wheel W being used to drive back the butt- 



