THE MOLECULAR FORCES IN PLANTS. 247 



number of cubic centimetres of Nitrogen evolved, the temperature 

 indicated by the thermometer in the cylinder, and the barometric 

 pressure. The reductions of the gas volumes are easily carried 

 out by means of the tables accompanying the apparatus. 



1 A full account of the absorptive capacity of the soil, and its causes, will be 

 found in Detmer, Lehrbitch d. Bodenknnde, Leipsic, 1876. 



