— 130 — 



boiling for 10 seconds more. Pine-tar oil turns brown, the hydro- 

 chloric acid brown to black. Turpentine oil gives much paler tints. 

 2. To a mixture of 4 cc. each of ferric chloride (1 :2500) and potassium 

 ferricyanide solution (1:500) add from 2 to at most 10 drops of 

 the oil to be tested and shake the whole vigorously. Pine-tar oil 

 will rapidly give a copious precipitate of Prussian blue, whereas 

 turpentine oil only gives a perceptible separation of that body after 

 the lapse of some hours. 

 C. Piest 1 ) proposes the following reaction to effect the same object: — 

 Shake in a test-tube 5 cc. acetic anhydride with 5 cc. turpentine 

 oil, and add 10 drops concentrated hydrochloric acid while shaking 

 and cooling. When the mixture has cooled down completely add, 

 with shaking, 5 drops more of concentrated hydrochloric acid; this 

 will cause the liquid to become warm and to make a clear solution. 

 Turpentine oil then remains water-white, pine-tar oil turns black. 

 In every case the turpentine oil, whatever its origin, should be dis- 

 tilled before being tested. 



In commenting upon a paper by Grimaldi on the detection of cam- 

 phene in light resin oil and in other oils 2 ), we took exception, in a foot- 

 note, to the use by Grimaldi of the designation "turpentine-essence" for 

 light resin oil, because, especially in translating, the term encourages con- 

 fusion with turpentine oil. In a letter which he has addressed to us 

 Grimaldi disowns the authorship of the term, and declares that he has 

 taken it from a paper by Valenta 3 ), who may possibly have borrowed it 

 himself. It is also necessary, Grimaldi observes, to differentiate between 

 turpentine essence, and light resin oils or pinoline; the last-named being 

 that product of the distillation of colophony which passes over at up to 

 about 230°, whereas "turpentine essence" constitutes the most volatile 

 fractions of that distillation, boiling over between 160 and 170°. 



We admit that in our footnote we drew no such sharp distinction 

 between the two distillates, as we did in previous Reports 4 ). That, any- 

 how, was not our principal object, which was chiefly to enter a protest 

 against the use of the name "turpentine essence" as inappropriate, without, 

 however, expressing an opinion on the authorship of the term. And on 

 the point to which we attach the most importance, Grimaldi agrees with us. 



Valerian Oil. We always have at our disposal considerable quantities- 

 of superior oil of our own distilling and shall be pleased to submit special 

 offers when quantities of some importance are in question. This article 



!) Chem. Ztg. 36 (1912), 198. 



2 ) Report April 1911, 118. 



3 ) Chem. Ztg. 29 (1905), 807; Report October 1905, 70. 



4 ) As, for example, Report October 1905, 71 ; April 1908, 105. 



