440 THE YOUNG FARMER'S MANUAL. 



so with hard- wood lumber, for slitting which a saw tl^ is just 

 large enough to reach through a board or plank to beJJed will 

 saw smoother than a larger saw, that will cut more square a'cross 

 the lumber. 



684. In sawing logs into boards, either with an up-and-down^ 

 saw or with a circular saw, the larger the logs are the greater 

 must be the power in order to do a profitable business. A power 

 that will do a good business at sawing logs from one to two feet 

 in diameter into lumber, if the power be all absorbed in sawing 

 such logs, will be insufficient to drive a saw at a good velocity 

 through logs from three to four feet in diameter. It is all folly 

 to attempt to do a fair business in sawing anything thick and 

 heavy, with a weak or limited power. If, in erecting a steam 

 saw-mill, the logs are of an average large size, it would be infi 

 nitely more profitable to the proprietor to have an engine say of 

 not less than thirty-horse-power, that would drive a saw with a 

 good speed through any log, however large and hard it might be, 

 than it would to use an engine of ten or fifteen-horse-power. 



685. In slitting lumber with my two-horse-power, with a cir 

 cular saw one foot in diameter, I found by experiment that with 

 a pulley six inches in diameter on the mandrel I could saw only 

 about half as fast with the horses travelling at a given gait as 

 I could when the pulley was about eleven inches in diameter. 

 With the small pulley too much of the power was absorbed in 

 producing a given velocity. The difference was not so percepti 

 ble when sawing thin stuff as it was when sawing plank two or 

 three inches thick. 



A WORD ABOUT FILES. 



686. My rule in selecting files is, to choose those that have a 

 clear, bright, and lively appearance, and that are well cut, having 

 sharp corners. If the corners are full which is of the greatest 

 importance the sides will be correspondingly sharp. If the cor 

 ners are not full, it is a pretty certain evidence that the temper is 

 not right, generally too hard, and they will not do good ser- 



