242 M. Marcet on the Changes which the Atmosphere 



The analysis gave : The receiver contained, before the experi- 

 ment, oxygen gas 24.21 ; after the experiment, oxygen gas 8.46, 

 carbonic acid 8.17, nitrogen gas 6.12, = 22.75. 



We perceive that in this experiment 15.75 cubic feet of the 

 24.21 disappeared. These 15.75 had been replaced by 8.17 of 

 carbonic acid, and 6.12 of nitrogen. 



4th Experiment. — Two specimens of the species Lycoperdon 

 bovista, the fuzz -bail, weighing, the one 65 grains, and the other 

 35, were introduced under the bell-glass enclosing 24.50 cubic 

 feet of oxygen. At the end of ten hours the volume of gas was 

 reduced to 23.63 cubic feet. The receiver contained, before the 

 experiment, oxygen gas 24.50 ; after the experiment, oxygen 

 gas 8.46, carbonic acid 8.46, nitrogen gas 6.71, = 23.63. 



There disappeared in this experiment 16.04 of the 24.50 cu- 

 bic feet of oxygen. Of the 16.04, 8.46 reappeared under the 

 form of carbonic acid, and the remainder appears to have enter- 

 ed into the mushrooms, and to have been replaced by the 6.71 

 of nitrogen. 



Sect. III. On the Action of Mushrooms on pure Nitrogen Gas, 



1st Experiment. — Four individuals of the species Boletus ver- 

 sicolor, removed from the trunk of an oak, imbedded in the 

 wood to which they were attached, were placed under a receiver, 

 containing 29.17 cubic feet of nitrogen, the thermometer stand- 

 ing at 66° Fahr. At the end of twelve hours the volume of gas 

 amounted to 29.75. The following is the result of the analysis. 

 The receiver contained, before the experiment, nitrogen gas 

 29.17 ; after the experiment, nitrogen gas 28.59, carbonic acid 

 1.16, =29.75. 



Here we find 0.58 of the nitrogen had disappeared during the 

 time the mushrooms remained in it, and was replaced by 1.16, 

 exactly double the quantity, of carbonic acid. 



2c? Experiment. — Two mushrooms of the species Lycoperdon 

 bovista, weighing together 100 grains, were placed during twelve 

 hours under a receiver, containing 26.25 cubic feet of nitrogen, 

 the thermometer at 63° Fahr. The following were the results. 

 The receiver contained, before the experiment, nitrogen gas 

 26.25; after the experiment, nitrogen gas 25.96, carbonic acid 

 .58, = 26.54. 



