AGRICULTUEAL CHEMISTRY AGEOTECHNY. 413 



Satisfactory results were obtaiued with a modification of the Toth method, 

 which is described. The results obtained with it agreed well with those yielded 

 by the Kissling method (E. S. R., 25, p. 16), but the author considers it im- 

 possible to obtain correct results with the Ulex method (E. S. R., 25, p. 211). 



Comparative investig'ations in reg'ard to the examination of tobacco ex- 

 tracts, J. Toth iCliem. Ztg., 35 (1911), No. 101, pp. 926, 927).— A comparative 

 study of the Kissling, Ulex. De Grazia, Toth, and Koenig methods was made. 



The results show that the Ulex method gives the highest results. The De 

 Grazia method is very simple and very quickly executed, and can therefore 

 be used for the examination of tobacco extracts in general. The only objec- 

 tion which can be raised against the method is that it is necessary to obtain 

 more than 180 cc. of distillate in order to get accurate figures. For tobacco 

 the results with the De Grazia method are unfavorable. 



The toluol solution used in the Koenig method was found to be too dark 

 for polarization, but when xylol was used the results obtained by polarization 

 corresponded well with those obtained by titration. The titration results with 

 the Koenig method agree very well with those obtained by the Kissling and 

 Toth methods. 



In reg'ard to the determination of nicotin in tobacco extracts, W. Koenig 

 (Chem. Ztg., 35 {1911), No. IIJ/, pp. lOP, i 0^8). —Commenting on Toth's criti- 

 cism of the Koenig method, this author points out that he never experienced 

 any difficulties in polarizing the toluol nicotin solution of tobacco extracts. He 

 believes that Toth probably used a very weak light. In addition, when xylol 

 was employed the specific rotation of nicotin must be considered 173 instead of 

 170, which it has in toluol. 



Nicotin in wastes from tobacco plants, Chuard and Mellet (Abs. in Chem. 

 Ztg., 35 (1911), No. 19, p. i77).— The stalks, shoots, etc., of the tobacco plant 

 contain considerable amounts of nicotin. The author proposes to make in the 

 near future a study of the distillates and the variations therein from the 

 different parts of the plant. 



Wood turpentine: Its production, refi.ning', properties, and uses, F. P. 

 Veitch and M. G. Donk (U. 8. Dept. Agr., Bur. Chem. Bill. lU, pp. 76, figs. 

 Ji). — This bulletin discusses the feasibility of preparing wood turpentine (stump 

 turpentine or wood spirits) from resinous woods, particularly from waste pine, 

 fir, or spruce wood. This form of turpentine when properly distilled closely 

 resembles gum turpentine. 



The subject is considered under the headings of methods of production, in- 

 cluding destructive distillation, steam distillation, extraction with solvents, 

 refining wood turpentine and wood oils; equipment for the manufacture of 

 wood turpentine ; cost of producing wood turpentine ; yields of various products 

 from the distillation of resinous woods ; properties and composition of wood 

 turpentine ; pine oils ; principles of fractional distillation ; use of the periodic 

 column still ; use of the pot still ; commercial opinions as to the value of wood 

 turpentine ; and the value of wood turpentines as paint and varnish thinners. 



Some experiments in refining wood turpentine show " that the percentage 

 of oils in the distillate furnishes the most reliable and useful information as 

 to the progress of distillation and the nature of the oils at different times, and 

 this is also the simplest means of acquiring such information. Neither the 

 specific gravity of the oils nor the temperature of the distilling vapors at the 

 top of the still furnishes as reliable information, nor are they so conveniently 

 determined. The temperature of the vapors is materially affected by the 

 volume and temperature of the steam entering the still and by variations in 

 atmospheric pressure. The former can of course be made practically constant 



