17+ 



THE POPULAR SCIENCE MONTHLY. 



trivance, and the bar of iron is cut with the same ease as though it 

 were of lead. This results to some extent from both jaws approach- 

 ing each other. The arrangement of levers, cams, and stays, is 

 worthy of examination after the lecture. 



' Fig. 1. 



The use of the chisel, however skillfully handled, is not satisfac- 

 tory over a surface wider than itself, although widened and made two- 

 handed, as Fig. 5, and although the gouge has succeeded, or rather 

 been planned to precede it, there is still a tendency almost uncon- 

 querable for the tool to follow the leadings of the fibres rather than 

 cut through them at a very slight obliquity. 



D 



Fig. 2. 



The only guidance either the axe, the adze, the pick, the gouge, 



or the chisel receives, is from the skill of the workman. Hence these 



tools produce such different work in different hands. However much 



it may be desirable to encourage skill in the workman, it is quite as 



. desirable to furnish him with implements which shall make the least 



Fig. 3. 



demand upon the exercise of this skill which shall, in fact, so assist 

 the skill in one or more directions as to permit all its care in some 

 other direction. The assistance which the chisel needs is such as 

 shall not only prevent it running deeper into the timber than is de- 



