undergoes when in contact with Vegetables. 241 



for twelve hours. At the expiration of this time, the volume of 

 gas in the receiver was found to be reduced to 26.54 cubic feet. 

 Its analysis gave the following result : The receiver contained, 

 before the experiment, oxygen gas £7.13 cubic feet ; after the 

 experiment, oxygen gas 14.79, carbonic acid 6.27, nitrogen gas 

 5.48, = 26.54. 



It will be seen by this result, that 12.34 cubic feet of oxygen, 

 that is, nearly the half of what was included in the bell-glass, 

 disappeared whilst the mushrooms remained in it. Of the 12.34 

 cubic feet of oxygen, 6.27 had combined with the carbonic of 

 the plants to produce carbonic acid gas, whilst the other 6.07 

 appears to have incorporated itself with the mushrooms, and to 

 have been replaced by 3.15 of nitrogen. 



This arrangement, repeated during twelve hours of the night, 

 furnished a result almost exactly the same as the preceding. 



2d Experiment. — Three mushrooms of the species Boletus ver- 

 sicolor, weighing together 125 grains, were detached with care 

 from the old trunk of an oak tree, so that a thin slice of wood 

 remained attached to each mushroom. They were placed under 

 a receiver containing 29.17 cubic feet of oxygen, whilst the ther- 

 mometer was at 58° Fahr. There they continued during thirteen 

 hours, being seven during the day, and six during the night. 

 At the end of this time, the gas only occupied 26.83 cubic feet. 

 The following is the analysis : The receiver contained, before 

 the experiment, oxygen gas 29.17 ; after the experiment, oxygen 

 gas 8.45, carbonic acid 11.96, nitrogen gas 6.42, == 26.83. 



There disappeared whilst the mushrooms remained in the jar 

 20.72 cubic feet, that is to say, nearly three-fourths of the whole 

 quantity. Of these 20.72 cubic feet, 11.96 combined with the 

 carbon of the vegetables to form an equal volume of carbonic 

 acid, which was found in the receiver ; the remaining 8.76 cubic 

 feet of oxygen appear to have remained combined with the mush- 

 rooms, and to have been replaced by 6.42 of nitrogen. 



3d Experiment. — Many small clustering mushrooms of the 

 species Agaricus pidvendentus, weighing 100 grains, were placed 

 for twelve hours, nine during the day, and three during the 

 night, under a receiver containing 24.21 cubic feet of oxygen 

 gas, the thermometer standing at 65°. At the expiration of 

 twelve hours, the volume of gas was found reduced to 22.75. 



