— 94 — 



and the unsaturated compounds. The terpenes, however, are also 

 attacked by strong sulphuric acid. 



Whether Finnish pine tar oil, which according to Aschan's 

 examinations contains only 6,i4°/ pinene, and for the rest consists 

 of sylvestrene, 1-limonene and dipentene, can also be employed for 

 therapeutic purposes, is a question which still remains to be solved. 



Before the New England Section of the Society of Chemical 

 Industry 1 ), Teeple read a paper on the production of turpentine oil 

 from waste wood. Starting from the well-known method of pro- 

 duction of turpentine resin, Teeple stated that in the last few years the 

 "cup and gutter" system of tapping had been adopted more and more, 2 ) 

 as this does not make such a heavy demand on the trees as the old 

 "boxing" system. Owing to the fact that the tree is constantly 

 wounded afresh, the wood in the last-named method is in the 

 neighbourhood of the wound in time entirely blocked up by rosin 

 ducts, the content of which differs from the exuding resin only by 

 a somewhat lower oil-content. If the tree breaks from any cause 

 whatever — either by winds, or by loss of vitality, — the wood 

 saturated with rosin (so-called "light wood") remains standing up 

 to the height of the tappings, say about 10 to 15 feet; the 

 content of rosin protects this "light wood" from rotting which 

 rapidly attacks the sap wood. As long ago as 1841 it was started 

 to make use of this "light wood" — which for the rest is very 

 heavy, and probably owes its name to the fact of its being used 

 for torches — by submitting it to dry distillation. An equally rich 

 yield of wood spirit, acetic acid, charcoal, gas, and tar was hoped 

 for, as from "hard wood", but experience showed that a great mistake 

 had been made in calculating the yield of these products, and partly 

 also in their utilisation. Various modifications of the retorts, and 

 alterations of the apparatus and the working methods, did not lead 

 to the desired end, so long as the process was based upon the 

 principle of dry distillation. More successful were the trials, first 

 made as long ago as 1865, and recently repeated, to heat the wood in 

 rosin-baths, and blow in steam; but this method had the disadvantage 

 of heavy expense and risk of fire, whilst the yields also fell short of 

 the expectations. Next Hull's process (1864) was tried, in which the 

 ground wood was distilled in vertical retorts heated from beneath with 

 superheated steam. This process has in practice the disadvantage that 

 the hot steam at once chars a portion of the wood, and consequently 

 effects partial dry distillation, the products of which pass over as 

 impurities of the turpentine along with the latter; moreover, not sufficient 



1 ) Journ. Soc. chem. Industry 20 (1907), 811. 



2 ) Comp. Report April 1906, 65. 





