42 



amount of rosin. A part of heartwood having twice as much rosin as another part will contain 



more than twice as much volatile products as the second part. This is true in a general sense of 



parts of the same disk, of parts of different disks in the same tree, and parts from different trees; 



there is no distinction in that respect between bled and unbled trees. This relationship can be 



formulated in the following way: The crude turpentine from heartwood rich in oleoresin, wUl 



yield a comparatively larger amount of turpeutine oil than the turpentine from heartwood poor in 



oleoresin. 



It has been shown that the heartwood grows poorer from Ih towards the pith of the tree. It 



T 

 will therefore follow from what has been said in the preceding paragraph that — will also grow 



H 



smaller from Ih to the pith. The yield of volatile oil from a constant quantity of turpentine can 



be expressed in a general way by a graphic illustration similar to that which expresses the yield 



of total oleoi'esiu from different parts of tlie disk. 



Hla 



Fifi. 21.— Yield "I' volatile nil from i-(>iist,:nit iiiiaiitily nf turiM-atine 



It is difficult to explain satisfactorily this decrease of . The two parts of the radial sections 



that have been the longest exposed to air arc. l.v and the last /(. the ijuestion naturally arises — 



T 

 May not the decrease of ^be due to a greater evai)pration of volatile hydrocarbons from these 



two ends? But this can hardly be so. S;}, II, -ih was analyzed at intervals of two months and 

 furnished the following data: 



Calculated for wood free from moisture: 



Sufficient experimental data are lacking to prove conclusively that the volatile hydrocarbons 

 do not evaporate to any extent from the heartwood, except from freshly cut surfaces of it. 



Relation, hctn^een (liffereitt (lisls of the .same tree. — There is no constant relation between the 

 different disks of the same tree so far as the amount of oleoresin is concerned. Although the disks 

 do vary from each otlier, the variation can not be connected with gravitation by virtue of which 

 the lower disks would contain a larger amount of turpentine than the upper ones; for different 

 trees vary from each other considerably in that respect, the variation being apparent in both bled 

 and unbled trees. If a, b, c stand for the amounts of oleoresin in disks denoted by Roman numbers, 

 the relative magnitudes being represented by the letters in the alphabetic order, then the results 

 of analysis can be condensed in the following table for the trees denoted in Arabic numbers : 



