194 FELLING AND CONVERSION OF TIMBER. 



smaller ones and for trees with knots than for even-grained 

 wood ; the degrees of resistance offered by woods of different 

 species of trees to sawing have been already given (p. 114). 



The measure of the work done by a saw is the surface sawn 

 per minute, measured in square feet ; a good cast-steel saw 

 frequently will do three times the work of inferior saws, and 

 thus will save labour considerably. In transporting saws, the 

 teeth should be covered by a wooden sheath, both to protect 

 them, and the transport employees. 



[Pit-saws (Fig. 118) for longitudinal sawing are not so much 

 used in forests as was formerly the case, owing, to the fact 

 that, generally, logs are removed in the round from forests and 

 converted into planks, etc., in sawmills. Pit-saws are, how- 

 ever, used still in the Foret Mormal, in France, for sawing 

 curved oakwood for barges. Such saws also are used largely 

 in Indian forests ; also frame-saws (Fig. 119) which have very 

 thin blades and are easily transportable, the frames being 

 made in the forest. *In Indian saws also the teeth are filed 

 so that the cutting edge is towards the operator, and much 

 thinner blades can be used than when the saws cut in thrust 

 as in Europe. Tr.] 



3. Tools for Splitting Wood. 



For splitting wood and also for felling trees iron or wooden 

 wedges and the cleaving-axe are required. 



(a) Wedges. Iron wedges have usually a wooden head, 

 which is surrounded by an iron ring to prevent it from split- 

 ting (Fig. 120). Wedges may be made also entirely of iron, 

 but they are then driven into the wood by a beetle or wooden 

 mallet, whilst the wooden-topped wedges may be driven in 

 with the flat steel back of a splitting axe. 



Wooden wedges (Fig. 121) are prepared by the woodcutter 

 out of tough middle-aged beech or hornbeam wood, and 

 frequently are surrounded at the head by an iron ring. 



Iron wedges are considered more serviceable for splitting 

 tough wood; when wooden wedges are used, a cleft must 

 be made previously in the wood with a cleaving axe. There 

 is, however, a risk that iron wedges may spring out of the 



* Fernanda, " Utilization of Forests," p. SO. 



