— 127 — 



is very different from the above. As a rule it is collected in the following two 

 or three fractions: wood turpentine proper, b. p. 150 — 160° up to 175—180°; 

 light pine-tar oil, b. p. 170—180° up to 210—225°; heavy pine-tar oil, 

 b. p. 180—190° up to 230—240°. The first fractions contain chiefly pinene, 

 also camphene, limonene, dipentene, and cineole, and (in case of careless 

 fractionation) more or less terpinene, borneol, and terpineol. The pine-tar 

 oil portions contain, in addition to small proportions of the terpenes, chiefly 

 terpineol, borneol and fenchyl alcohol. A great many attempts have been 

 made to free wood turpentine from its characteristic objectionable odour. 

 It is true that the very first fractions of the steam-distilled oil have a 

 pure odour, but the yield is too small to justify the rejection of subsequent 

 fractions to make it practicable to collect them by themselves, and per- 

 haps to disregard the succeeding fractions. Special experiments carried 

 out by the Department have shown that the unpleasant odour attaches 

 principally, although not entirely, to the higher boiling portions which are 

 still included in the low-boiling fraction, and special importance is to be 

 attached to the removal of these by carefully-conducted fractionation. When 

 this is done, however, wood turpentine very closely resembles genuine 

 turpentine oil, both in its odour and in its constitution. The following 

 table shows the properties of the usual commercial turpentine oils: — 



Constants 



Gum 

 Turpentine oil 



Wood turpentine oil 



Steam-distilled 



by 



destructive process 



dzoo 



«D20O 



"d20O 



Initial distilling point (uncorr.) 



Distilling below 170° 



Distilling below 185° 



Iodine value according to Wijs 



Acid v 



Sap. v 



Color (Lovibond) 



for yellow 

 for red 



0,8617 to 0,8889 



-34,8° 



1,4684 



154 



73 



88 



350 



0,140 



2,44 



-|-29,6 C 



1,4818 



159° 



99°/o 



99°/o 



400 



0,286 



8,60 



0,7 „ 2,5 

 0,0 „ 0,5 



0,859 to 0,915 

 4-16,5° „ +36,14° 



1,4673 



153 







20 



300 



0,080 



1,06 



0,5 

 0,2 



1,4755 

 177° 



950/0 



98»/o 



362 



0,312 



8,75 



10,0 

 1»4 



0,857 to 



+ 34,4° „ 



1,4666 „ 



150 „ 



„ 



61 „ 



300 „ 



0,028 „ 



0,65 „ 



0,4 

 0,0 



0,898 



+ 77,6Q 



1,4810 



169° 



93% 



970/0 



398 



0,246 



4,32 



4,5 

 0,8 



The iodine-value is regarded as of significance, inasmuch as it indicates 

 the proportion of heavy oil; but similar conclusions may be drawn from 

 fe saponification-value. Comparison of the crude with the rectified oils 

 and their constants shows that rectification, as it is carried out in practice 

 up to the present, hardly improves the quality, but only produces a dis- 

 tillate of a paler colour. The authors of the report go into full details 

 on the subject of the experiments in fractionation which they conducted 

 on a large scale, both in a simple and in a column still with direct 

 steam. So far the record of the working showed no considerable difference 



