170 ELEMENTARY FORESTRY. 



method, and requires very different management. The more 

 nearly perfect the quarter-sawing is done the more waste there 

 is, and so it is the object of practical men to avoid the extremes 

 of perfect quarter-sawing (at great expense in labor and mate- 

 rial) and through-and-through sawing (which is cheapest and 

 most economical of material). In ordinary quarter-sawing of 

 this kind there is a waste of twenty to thirty per cent in material 

 as compared with through-and-through sawing. This waste is 

 found in the feather edged pieces and bevelled edges which have 

 to be cut off, and in the very narrow strips of no value. Small 

 logs waste much more than large logs in quarter-sawing. Most 

 sawyers place the minimum sized log that should be used for 

 quarter-sawing at twenty-six inches in diameter. It is very 

 important to have quarter-sawed lumber wide, as narrow stock 

 is of comparatively little value. In ordinary sawing there are 

 always a few cuts made parallel to the silver rays which have the 

 desired quarter-sawed figure. 



In practice, several methods of sawing are used to bring out 

 the silver grain. The most common is to quarter the logs, and 

 then saw each quarter, as shown by the lines in Figure 45. 



FUEL VALUE OF WOODS.* 



1 'The Relative Fuel Values here given are obtained by 

 deducting the percentage of ash from the specific gravity, and 

 are based on the hypothesis that the real value of the combus- 

 tible material in all woods is the same. 



"It appears from Mr. Sharpies' experiments that resinous 

 woods give upwards of twelve per cent more heat from equal 

 weights burned than non-resinous woods; the heat produced by 

 burning a kilogram of dry non-resinous wood being about 4,000 

 units, while the heat produced by burning a kilogram of dry 

 resinous wood is about 4,500 units, a unit being the quantity of 

 heat required to raise one kilogram of water one degree centi- 

 grade. 



"Count Rumford first propounded the theory that the value 

 of equal weights of wood for fuel was the same, without reference 

 to specific distinctions; that is, that a pound of wood, whatever 



*This article on the fuel value of woods is taken from the "Report of 

 the Tenth Census," by Prof. C. S. Sargent. 



