Production1). As early as 1841 attempts were made to utilize the "light wood", which name presumably owes its origin to the use made of it as torches 2), by subjecting it to destructive distillation. It was hoped that this wood might yield as much wood spirits, acetic acid, charcoal, gas and tar as did the foliage woods ("hard woods"). Experience, however, taught the error as to yield as well as to the application of the products. Modifications as to retorts, benches and mode of operation, however, did not yield results so long as the principle of destructive distillation was employed. More successful were the attempts first made in 1865 and recently renewed, to heat the wood in resin baths and to inject steam. This method, however, had the disadvantage of high cost as well as danger from fire. Moreover, the yields did not meet the expectations. Hull's method was next tried (1864). In upright stills the comminuted wood was distilled with superheated steam. Experience taught that the superheated steam at once carbonizes a part of the wood and thus results in destructive distillation, the products of which enter the turpentine oil as impurities. Moreover, insufficient care was bestowed upon the uniformity of superheating. The use of non-superheated steam, employed as early as 1864 by Leffler, but forgotten and recently recommended by Krug, appears to be more promising. The wood is first exhausted withsteam and then subjected to destructive distillation or worked up in some other manner. Great care is bestowed upon the engineering aspects of the industry: the filling and emptying of the retorts, the proper distribution of steam, the stirring of the wood within the retort etc. According to Teeple, the yields according to this method amount to 25 gals, of oil per cord1) and average 12 to 15 gals. An exhaustive account of the experiences relative to production, purification and uses of wood turpentine oil was compiled by the Department of Agriculture in 1911 2). To enter upon further details of this interesting brochure would lead too far.

1) E.J.Teeple, Journ. Soc. chem. Industry 26 (1907), 811.

2) "Light wood" corresponds to the German Kienholz.

In 1910 there existed in the United States 30 factories-that distilled soft woods. Yellow pine was principally distilled, also smaller amounts of Norway pine and Douglas fir. The factories worked up 192,442 cords of soft wood, against 115,310, 99,212 and 62,349 cords respectively for the years 1909 to 1907, thus revealing the increasing importance of the wood turpentine industry.

Properties. Under the designation wood turpentine oil a variety of oils with differing properties is found in the market. This is due to the practice that the colorless oils with lower boiling points consisting essentially of terpenes (wood spirits of turpentine) are collected by themselves and kept separate from the higher boiling oxygenated portions (white and yellow pine oils)8).

A "clear" oil obtained in a laboratory experiment by W.H.Walker, E.W.Wiggins and E.C.Smith4) had the sp.gr. 0,865 to 0,867. Eighty per cent, thereof distilled over below 163°, a yellow oil boiled between 200 and 214°. According to Teeple1), the sp.gr. of wood spirit of turpentine is about 0,865, that of pine oil between 0,935 and 0,947. The boiling temperature lies between 206 and 210°. 75 p. c. should distil over between 211 and 218°, and 50 p. c. between 213 and 217°. In connection with one sample the following constants were ascertained: d15,5o 0,945; [a]D abt. - 11°; nD 1,483. With the increased boiling point the density of the fractions increased, becoming constant at 217° (abt. 0,947). The samples of "yellow pine oil" examined by Schimmel & Co. varied in their properties from those recorded by Teeple. The density varied between 0,941 and 0,954 at 15°; the optical rotation between +6 and - 5°. As an illustration, one of these oils had the following constants: d15o,946; aD - 0°54'; nD20o 1,48393; A. V. 0,5; E.V. 0,9; E. V. after acetylation 186 (corresponding to 59,4 p. c. of alcohol C10H18O); soluble in 4 vol. of 60 p. c, in 2 vol. of 70 p. c. and 0,8 vol. of 80 p. c. alcohol. Another oil (for its constituents see "Composition") had the following constants: d15O0,9536; aD - 3°26'; nD20o 1,48537; A.V. 0; E.V. 14,2 (corresponding to 4,9 p.c. ester C10H17Ococh3): E.V. after acetylation 161,4 (corresponding to 50,5 p. c. alcohol C10H18O). By means of acetylation in xylene solution, the alcohol content was ascertained to be 58 p. c. The boiling temperature of the principal fraction lay between 190 and 220° (5 p.c. passed over between 160 and 190°).

1) 1 cord (Ger. Klafter) is a cubical measure 8X4X4 feet.

2) F. P. Veitch and M. G. Donk, Wood turpentine, its production, refining, properties, and uses. U. S. Dept. of Agriculture, Bur. of Chemistry, Bulletin No. 144, 1911; Report of Schimmel & Co. April 1912, 126.

3) Similar products are also obtained upon the distillation of the waste of saw mills. Comp. Teeple, loc. cit.

4) Chemical Engineer (Philadelphia) 3 (1905), 78.

In the brochure published by the Department of Agriculture and referred to on p. 98, footnote 2, the following constants are enumerated for wood turpentine oil distilled with steam: d20o0,859 to 0,915; aD20O +16,5 to +36,14°; nD20o1,4673 to 1,4755; it begins to boil at from 153 to 177°, 0 to 95 p.c. passing over up to 170°, and from 20 to 98 p. c. up to 185°; iodine value according to Wijs 300 to 362; A. V. 0,080 to 0,312; S. V. 1,06 to 8,75; colorimetric value (Lovibond) for yellow 0,5 to 10,0 for red 0,2 to 1,4.

Composition. Walker, Wiggins and Smith2) were the first to examine wood turpentine oil. From the formation of a chlor1) Journ. Americ. chem. Soc. 30 (1908), 412 and Seventh International Congress of Applied Chemistry, London 1910. Section IV. A. 1, p. 54. 2) Loc. efthydrate melting at 50°, which they obtained by passing hydrogen chloride into fraction 209 to 211°, they inferred the presence of terpineol. Teeple proved the presence of this alcohol by converting it into terpin hydrate (m. p. 118°), terpineol nitroso-chloride (m. p. 101 to 103°) and terpineol nitrol piperide (m. p. 158 to 159°).