Chemical and Physical Papers. 53 



COMPOSITION OF GAS FROM COTTONWOOD TREES. 



By F. W. BusHONG. 



\ BOUT ten years ago, while cutting down some cottonwood 

 -^ trees, the writer observed the formation of bubbles in 

 the sap upon the freshly cut trunk, stump and chips. On ap- 

 plying a lighted match the gas emitted proved to be combus- 

 tible. In the latter part of July, 1907, gas was collected from 

 a cottonwood tree in the following manner : 



An inch hole was bored into the trunk to the heart. A piece 

 of gas-pipe provided with' a stopcock was screwed tightly into 

 this hole. A rubber tube conveyed the gas from the stopcock 

 to a bottle previously filled with distilled water and inverted 

 in a dish of distilled water. Two bottles of gas, about four 

 liters, were collected and used for preliminary experiments, 

 but were not used for analysis because they contained the air 

 originally in the gas-pipe, etc. A third bottle of gas was re- 

 served for the analysis, which was made November 27, 1907, 

 with the following average results from two complete and 

 two partial analyses by Professor McFarland: 



Oxygen, 0= 1.24 



Carbon dioxid, CO2 7.21 



defines (ethylene) , etc., aH4 0.00 



Carbon monoxid, CO 0.00 



(One determination gave 0.5 per cent.) 



Hydrogen, H= 0.00 



Methane (marsh gas), CH* 60.90 



Ethane, etc., C2He 0.00 



Nitrogen, etc., by difference, N2 30.65 



Total 100.00 



Nitrogen residue as actually determined, N2 30.01 



University of Kansas, Lawrence, November 27, 1907. 



