78 S Y L V A BOOK in 



excavating of columns, to preserve their shafts from 

 splitting, to which otherwise they are obnoxious. 



The frames of both these instruments discover 

 themselves sufficiently to the eye, and therefore will 

 need the less description : There is yet this reformation 

 from those which they use both in Norway, and 

 Switzerland ; that whereas they make the timber ap- 

 proach the saws, by certain indented wheels with a 

 rochet (which is frequently out of order) there is in 

 the first figure, a substitution of two counterpoises of 

 about three hundred pound weight, each as you may 

 see at A. A. fastning the cords to which they append, 

 at the extreams of two movable pieces of timber, 

 which slide on two other pieces of fixed wood, by the 

 aid of certain small pullies, which you may imagine 

 to be within an hinge in the house or mill, by which 

 means the weights continually draw and advance the 

 moving pieces of wood, and consequently the timber 

 to be slit, fastned 'twixt the said pieces, towards the 

 teeth of the saws, rising and falling as the motion of 

 the wheel directs : And on this frame you may put 

 four or five saws, or more if you please, and place them 

 at what intervals you think fit, according to the 

 dimensions which you design in cutting the timber 

 for your use ; and when the piece is sawn, then one 

 or two men with a lever must turn a roller, to which 

 there is annext a strong cord, which will draw back 

 the piece, and lift up the counter-poise ; and so the 

 piece put a little towards one side, direct the saws 

 against another. 



The second figure for boring, consists of an ax-tree, 

 to which is fastned a wheel of six and thirty teeth, or 

 more, as the velocity of the water-motion require ; 

 for if it be slow, more teeth are requisite : There 



