[hardy] destructive DISTILLATION YIELDS 113 



Apparatus and Methods 



A retort (Fig. 1) was constructed of a 24-inch length of 6-inch 

 steel pipe fitted with standard fîanges on the ends and a one-half 

 inch delivery pipe in the top and a gland in the end for the pyromete ■ 

 element. This retort was heated by two coils of twenty turns each 

 I X .010 Nichrome tape on a llOvolt circuit. The retort was 

 horizontal and blank flanges were fitted at the ends with asbestos 

 gaskets. The whole was well insulated by 85 per cent, magnesia 

 lagging and sheet asbestos wrappings. The distillate was condensed 

 by two large Liebig condensers in series with a trap between. The 

 gases were not measured. A study of the yield and composition of 

 the gases from Douglas fir has been made by Tremper {Jour. Ind. and 

 Eng. Chem. 7, 926, 1915). 



r3lSTILLATION 



The retort was charged with wood cut to the size of kindling in 

 eleven inch lengths. The distillation usually required from six to 

 eight hours and a final temperature around 700°F. was reached. 

 The rate of heating and the temperature varied somewhat with the 

 amount of moisture in the various samples. 



Treatment of Distillate 



The entire distillate was allowed to stand for several days in a 

 large graduate until most of the tar had settled. A 400 c.c. sample 

 of the clear liquid was distilled until a boiling point of 130°C. was 

 reached. The volumes of the distillate and residue were measured. 

 A sample of the distillate was titrated with half-normal sodium 

 hydroxide and a second larger sample (250 c.c.) was neutralized with 

 lime and fractionally distilled. The gravity of this second distillate 

 was obtained by means of a Westphal balance. 



Notes on Methods of Calculation 



The weights of wood and charcoal were obtained i)\- direct 

 weighing and need no explanation. 



The volume of tar reported is the sum of the tar which separated 

 on first standing and the tar as obtained by a redistillation of the 

 clear liquid. 



