DISTILLATION' OF STUMPWOOD. 



or air spaces, the weight decreasing as the cubical content increa 

 An increase of about 10 per cent is said to result from reduc 

 average cordwood to the size in which the wood making up 

 samples used in this work was piled and measured, from wl 

 it would appear that the weights per cord on which the yields 

 computed should be increased by 10 per cent. Owing, however 

 the irregular shape of the pieces of stump cordwood and the i 

 observed in piling the reduced wood closely, it is believed that 

 observed weights are not essentially lower than the average we 

 of a commercial cord of western yellow-pine stumpwood of co 

 sponding quality. In support of this it was found that of tl 

 cords of stumpwood from near Deary, Idaho, piled and measi 

 in the field, when corded again after having been reduced to 

 size in which they were used in the retort, one measured an t 

 cord, one 19 per cent less than a cord, and the third 10 per i 

 more than a cord. It seems unnecessary, therefore, to use o 

 than the observed weights in calculating results. 



The retort distillations were made on charges of known weig 

 varying from 150 to 200 pounds, depending on the nature of 

 wood. The distillation products were measured in liters per ch; 

 and the yields reported in gallons per cord. This basis of st 

 ment was selected in preference to the more exact unit-of-we 

 basis, the ton, for example, because of the difficulty of estima 

 the quantity of the several classes of wood on a given acre 

 applying the results to the problems in hand on other than 

 cord basis. The yields can be quickly figured to the ton basis f 

 the data given in Table 14. 



APPARATUS. 



In principle, the apparatus (figs. 3 and 4) is essentially an 

 jacketed retort (a) in which high-flash cylinder oil, heated to 

 desired temperature, is circulated through closely spaced hea 

 coils (5, c, and d) within the retort. The coil system of jacke 

 is preferable to a double shell in that it insures a positive flo\ 

 the heated oil, and, by dividing the coils into sections, prevent; 

 excessive drop in temperature between the incoming and outg< 

 oil. A 3-inch layer of asbestos lagging and pipe covering of 

 same material protects the retort and exterior piping against 

 cessive radiation. A coarse wire-gauze screen placed on the ja 

 coils facilitates removal of the charcoal. 



The motor-driven oil pump (/) takes oil from the overflow 1 

 (g) and discharges it through the gas-fired oil heater (e) into 

 jacket coils {b and c), from the other end of which it flows 1 

 into the tank (g). This circulation is maintained with the jacke 

 as it comes from the heater and is held at 260° C. as registerec 



