41 



wood can not he disregarded because it is as mncli an essential proximate constituent of wood as 

 the turpentine itself is. But since the analyses were not made soon after the trees had been felled, 

 the moisture fonnd in the samples does Tiot represent the original moisture, uor does it represent 

 e(|ual portions of it in all samples. Tlie numbers given iu the column '-water" are of course sug- 

 gestive as to tlu- comparative degree of retention of moisture by the dilferent samples, since the 

 latter were all exposed to about the same intlnences. lint it seemed best to compare the amouuts 

 of volatile hydrocarbons and rosin on wood free from that variable constituent; the more so as 

 some time elapsed between the analysis of the first and last samples. 



The last column in each table contains the ratio between the volatile hydrocarbons and rosin. 

 This ratio is multiplied by 100 and means that for every 100 parts (tf rosin as many parts of the 



volatile hydrocarbons are found as is indicated in the colnmn. This ratio ( p ) is of little value 



in cases when the amount of turpentine is small, because a very small increase of the first con- 

 stituent — an increase within experimental error — will change the (pioticnt considerably. An 



T 

 increase of 0.07 per cent of volatile hydrocarbons in (iO, IV, l.v will bring up ,, from T.li to 10. A 



decrease of 0.07 iter cent in 5li, IV, li.v will chan< 



T 



from 25.20 to alxiut 10. These numbers are 



therefore of very litth> significance when api)lied to the sapwood of all samples, to entire tree.r»2, 

 and to some parts of trees CO and 1, all of which show only small portions of turpentine. 



DISCUSSION IIF UESlTI/rS ( IIJTAINEI). 



Relation of rosin und rolatUe hydroi-dilmn to moisture. — The amount ol' moisture retained Ijy 

 different samples does not seem to have any direct relation to the amount of oleoresin in these 

 samjdes. Yet in the same tree, or rather in the different jiarts of the same disk, there seems to exist 

 something like a relation of the two. This is especially noticeable iu tree No. r»3. The moisture 

 retained seems to vary inversely with the amount of oleoiesin iu the sami)le. (Jompare for example 

 in 5;5 11, Ih, 2/(, ."./(; in o.'! Ill, l/t, 2/i., .y*, 17/; in o;5 IV, 2//, 3/(, 1/;. The piece richest in oleoresin 

 is generally the ])Oorest in moisture. But this is by no means a universal rule. Some trees show 

 about the same per cent of moisture iu parts widely ilitt'eriiig from each other in the amounts of 

 turpentine, and in many instances a snmller amount of turpentine is associated with a smaller ])er 

 cent of moisture. 



S(iiin-oo(] (Old heartirood. — All the analyses, detail aiul average, show conclusively that the sap- 

 wood is comparatively very poor in turpentine; it is inunatcrial whether it comes from a rich tree 

 or a poor one, from a tapped tree or an untapped one. The turpentine in sapwood reaches 3 to 4 

 per cent in very rich trees, as in Nos. :>?,, (11, and 2; in the renuiining trees it is 2 to ;! jter cent. 

 (;onse(pxently the results obtained for sai)woo(l aic; not taken into account in the following iiara- 

 graiihs. When dilferences between trees are spoken of, it applies entirely to heart-wood. 



The different jxiris of the xonie dink show a constant r(datioii in nearly all instances. In most 

 cases Ih is the richest, and the heartwood glows pooler as we approach the pith of the tree. In 

 a few cases, as in I 111 and in 1 IV, \h and 2// are practically identical, while in some instances, 

 ill 2 III, 01 II, 01 111, and 5;) 11, \h is poorer than 2/(. In nearly all cases the decline is marked 

 in .■{/(, and 4// is usually found to be the poorest part of the disk. This relationshii) can be repre- 

 sented in a general way by the following curve. 



Fhi. 20.— Kflntioiisliip of difloreiil, i nits (if same ilisk. 



Relation of volatile hydrocarbons to ronin.— As the turpentine in the tree is a solution of rosin 

 in an essential oil, it will follow that the richer a tree is in turpentine the richer it will be in the 

 constituents that go to nmke u)) this mixture. One would also expect that the ratio between the 

 volatile hydrocarbons and rosin would be tolerably constant in the different i)arts of (he same 

 tree. But the results of analysis do not indicate it. They show that this ratio increases with the 

 11500— No. 8 6 



