— 120 — 



stitute for pure oil of turpentine, it appears to us that the calculation 

 has been made on a very liberal scale. No data are given as to the 

 chief point, viz., the yield of "turpentine oil"; and it would also be 

 of interest to be informed how, by the process described, the rosin 

 is produced. 



The first part of the latest Scientific and Industrial Reports of 

 the firm of Roure - Bertrand Fils contains, inter alia, a paper by 

 M. Vezes 1 ) on the turpentine industry in the French Landes 

 and its products. Some years ago M. Vezes, with the assistance of 

 certain interested public bodies and private firms, established at Bor- 

 • deaux University a laboratory devoted exclusively to the study of 

 questions pertaining to the turpentine industry of South- Western France. 

 In his present paper he gives an account of the mode of collecting 

 turpentine in this region, accompanied by a number of illustrations. 

 The account shows how carefully the French forest - owners husband 

 their trees, in contradistinction to the wastefulness of the American 

 turpentine farmers. As pointed out in the preceding pages, the Ame- 

 rican Forest Department is now taking steps to induce the owners of 

 pine trees in the United States to adopt the French system of tapping. 

 Vezes further passes in review the work done in his laboratory, which 

 up to the present was chiefly devoted to physics. 2 ) The latest researches 

 of which he gives particulars relate to the highest admissible degree of 

 "normal impurities" in French oil of turpentine; by which he under- 

 stands the slightly volatile substances, and colophony, as well as the 

 degree of acidity. Small quantities of rosin pass over into the distillate 

 either mechanically or because they are of low volatility; if the work 

 of distilling is carried out in a slovenly manner it is self-evident that 

 larger proportions of rosin may be carried over. Following previous 

 proposals by Vezes, the Commercial Union of the Resin-Industry at 

 Bordeaux had fixed as the admissible maximum for turpentine oil 

 2,5 °/ of normal impurities and a degree of acidity not exceeding 

 1,0; the latter figure denoting the number of grammes of pure potas- 

 sium hydrate which suffices to neutralise I litre of the oil (using 

 phenol-phthalein as indicator). (Perhaps it would have been pre- 

 ferable, both for the sake of uniformity and in view of the variable 

 sp. gr. of the oils, if the acid number had been fixed per kilo of oil, 

 because in that case the acidity would have been identical with the 

 general acid number in essential oil investigations.) For oils which, 

 although free from "abnormal impurities" (benzene and petroleum 

 distillates) yet indicate higher proportions of rosin and acids, the follow- 

 ing classification has been laid down: i. A normal oil of fair market 



*) Berichte of Roure-Bertrand Fils, April 1909, 3. 



2 j See Reports April 1904, 86; April 1905, 76; April 1907, 99- 



