38 



Even had the tubes retained equal quantities of turpentine oil, this method would still have the 

 objection that one of the constituents Avas to be determined by ditt'erence — an objection esi)ecially 

 serious when the ingredient to be so determined is small in comparison witli the materials to be 

 weighed. 



The writer has therefore attempted to make use of a somewhat different principle. A few trials 

 were sufficient to show that the method x^omised to give satisfactory results. Tlie basis of the 

 method is the same which serves for the production of Eussian turpentine oil on a large scale, 

 namely, the distillation of the volatile products from the wood itself, without previously obtaining 

 the turpentine. But instead of condensing the volatile products, their vapors are passed over 

 heated copper oxide whereby they are burned to water and <;arbou dioxide. Many trials were 

 made with this method upon pure materials and on samples of resinoiis wood; as the results were 

 found to be entirely concordant and satisfactory, the method was adopted, and by it were obtained 

 the results presented in this report. 



DESCRIPTION OF THE METHOD EMPLOYED. 



A weighed amount of wood shavings is placed in a straigiit OaOU tube a. The tube is con- 

 nected on one side by means of a ca])illary tube with a drier A, which serves for freeing the air from 

 moisture and OO.. Tiie other end of the tube is connected with an ordinary combustion tube h 

 containing granulated GuO. The tube is drawn out at one end as is shown in the figure, and the 

 narrow portion is loosely filled with asbestos wool. The connection is made glass to glass, so that 



Fig. 18. — Method of distillutiuu uf liuiifutiue. 



the vapors of distillation do not come in contact with any rubber tubing. The forward end of the 

 combustion tube is connected with a OaCla tube c, (me-half of which is filled with granulated CaCU 

 and the second half with P2O5. Then follows a potash bulb d provided with two straight tubes, the 

 first one filled with solid KOH, the second with P2O3. The last tube is connected with an aspirator. 

 All the connections having been made air-tight, the connection between the tube a and the 

 drier A is shut off by means of a clamp and the aspirator turned on. When the combustion tube 

 Las been heated to dull redness the burner under the air-bath B is ht and the temperature raised 

 to lli)°-V2()° 0. The moisture contained in the tube escapes (juite rapidly, carrying with it some 

 turpentine oil. The capillary tube at the other end of a practically checks backward diffusion or 

 any accumulation of condensed vapors. In about 15 minutes all the moisture appears at the for- 

 ward end of the combustion tube. The clamp is now opened and a stream of air at the rate of 

 somewhat over one liter an hour is passed though tlie whole apparatus, while the temperature of 

 the air bath is raised to 155° to 16()o C, and kept at that point for about 45 minutes. Towards the 

 end of the operation the temperature is raised to 165° to 170° 0. for 10 minutes. Then the light 

 under the air-bath is turned off and air aspirated for 20 to 25 minutes longer. As the air- oath is 



