The total output of a "turpentine farm", of the size given on p. 61, for the period of 4 years averaged 120000 gals, turpentine oil, 5200 bbls. of rosin of first quality, 4000 bbls. of second grade, and 2400 bbls. of common rosin, also 1200 bbls. of the poorest quality without market value1).
Properties. As a rule the specific gravity of American turpentine oil varies between 0,865 and 0,870. However, lighter oils (sp. gr. 0,858) and heavier oils (up to 0,877 2)) are observed occasionally. Freshly distilled or rectified oil is as a rule lighter than crude or old oil.
When distilled in a fractionating flask, about 85 p.c. passes2) over between 155 and 163°. For the properties of the individual fractions of a carefully fractionated American oil see p. 19.
1) According to Dr. Carl Mohr's "Verbreitung der Terpentin Iiefernden Pinus-Arten im Suden der Vereinigten Staaten und fiber die Gewinnung und Verarbeitung des Terpentins". Pharm. Rundsch. (New York) 2 (1884), 163, 187.
2) E. Kremers, Pharm. Review 15 (1897), 8.
As a rule, commercial American turpentine oil is dextrogyrate; not infrequently, however, lasvogyrate. In 1884 Armstrong1) observed angles of rotation of + 13° 33' to +14° 17' in connection with 28 samples of turpentine oil from Wilmington; and of + 9o 30' to -h2°4' in connection with samples from Savannah. Two oils, obtained toward the close of the last century, from Savannah, were slightly laevogyrate: aD - 0°40'to - 2° 5'. For oils obtained directly from this port, Dr. C. Kleber observed as high as - 22° 30'2).
Fig. 7. Turpentine distillery of the older type.
1) Pharmaceutical Journ. III. 13 (1883), 584.
2) Private communication.
3) F. P. Veitch and M. G. Donk, Wood turpentine, its production, refining, properties and uses. U. S. Dept. of Agriculture, Bur. of Chemistry, Bulletin Mo. 144, 1911. p. 22.
Fig. 8. Distillation of Turpentine in North America.
d20 0,8617 to 0,8889; aD20o. - 34,8° to +29,6°; n D20.o 1,4684 to 1,4818; begins to boil (uncorr.) between 154 and 159°, 73 to 99 p.c. distilling over up to 170° and 88 to 99 p.c. up to 185°; iodine value, according to Wijs 350 to 400; A. V. 0,140 to 0,286; S. V. 2,44 to 8,60; colorimeter value (Lovibond) 0,7 to 2,5 for yellow and 0,0 to 0,5 for red.
The variation in the direction of the optical rotation is due to the fact that American turpentine oil is distilled from several species of Pin us. Long-leaved pine, Pin us palustris, yields dextrogyrate oil, Cuban or slash pine, Pinus heterophylla, laevo-gyrate oil. In the collection, the oleoresins of both are mixed indiscriminately resulting in variations of the optical rotation. Inasmuch as the oleoresin of Pinus palustris commonly predominates, the oil is mostly dextrogyrate.
C. H. Herty1) has made an interesting study of the optical rotation of the oils from the same tree for a prolonged period. Fourteen trees of a Florida turpentine farm were selected, half of which were Pinus palustris, the other half Pinus heterophylla. Three series of observations were made. For the first series three trees of each species were selected: a small, young tree, a medium tree, and an old large tree. For the second series two trees each of both species were selected which had yielded turpentine during the previous year, but which had been wounded only half as deep as customary. For the third series two trees of each species were selected that had been treated in the usual manner during the previous year.
The oils distilled from the oleoresins collected early in spring revealed great variation in their optical rotation. With two exceptions Pinus palustris yielded dextrogyrate oil, Pinus heterophylla lsevogyrate oil. In the course of the campaign six more samples were collected from each tree. In most instances the angle of rotation remained constant throughout the year. Owing to unexplained biological conditions, variations of the optical rotation were observed in three instances. The tree that showed the greatest variations was the one from which one would have expected it least, since it was healthy and strong throughout. Difference in the direction of the rotation was like1) Journ. Americ. chem. Soc. 30 (1908), 863. wise observed in connection with trees of the same species. Inasmuch as they grew under the same conditions of climate, light and soil, no explanation has been found for this phenomenon. Inasmuch as the oils, consisting largely of pinene, revealed no differences in their boiling temperatures, the mixtures appear to consist of d- and /-pinene. The direction of rotation is influenced by the predominance of the one or other modification.
The oils of Pinus Taeda, L. (Loblolly pine) and P. echinata, Mill. (Shortleaf pine) are almost identical with the oils of Pinus palustris, Mill, and P. heterophylla, (Ell.) Sudworth. Their principal constituent is a-pinene1).