12 Forest Mensuration 



TABLE SHOWING RELATIVE CONTENTS OF LOGS WITHOUT BARK. 



PARAGRAPH XX. 



XYLOMETRIC METHOD. 



The so-called "physical methods," by which the volume of a (partic- 

 ularly irregular) piece of a tree may be accurately found, require either 

 the submersion of the piece in water (xylometric method) or the weigh- 

 ing of the piece after finding its specific gravity (hydrostatic method, 

 8 XXX). 



The xylometric method can be applied in three ways, thus : 



a. Submerge the wood in a graded cylinder partly filled with water 

 and find the water level before and after submersion. 



b. Submerge the wood in a barrel partly filled with water; dip out 

 the water with a gallon measure until the water is as low as it was before 

 submersion. The number of gallons dipped out equals the volume of 

 the wood submerged. One gallon equals 231 cubic inches. 



c. Place a piece of wood in an empty barrel of known contents ; fill 

 to the rim with water by the gallon. The difference between the known 

 contents and the number of gallons required gives the quantity of wood 

 in gallons. 



In a, b and c it is necessary to use wood dry on the outside, to leave 

 the wood in the water a short time only, and to stir it up while in the 

 water so as to remove air bubbles. 



PARAGRAPH XXI. 



HYDROSTATIC METHOD. 



The hydrostatic method deals with specific gravities. Specific gravity 

 is weight of an object divided by the weight of an equal volume of 



