GAS FROM LEAVES CONTAINS NITROGEN. 



sorbed 3-50 measures of carbonic acid, the remainder being 44-00 measures ; 90 measures 

 of hydrogen were added thereto, making the full volume 134-00 measures ; a platinum 

 ball reduced this to 67-00 ; indicating 22-33 of oxygen, there remaining of nitrogen 

 21-67. The composition of this gas was, therefore, 



Oxygen 22-33 



Nitrogen 21-67 



Carbonic acid 3'50 



47-50 



To prove that the remainder here spoken of was really nitrogen, one hundred volumes 

 of the original gas were taken, and the electric spark passed through it ; there was no 

 diminution in the volume, nor any carbonic acid gas generated ; it could not, therefore, 

 be carbonic oxide, hydrogen gas. nor any of the carburets of hydrogen ; it possessed, 

 moreover, all the negative qualities of nitrogen. 



423. But the solution was composed of carbonic acid and water, great care having 

 been taken to cut off all access of the atmosphere during its preparation, and also during 

 its exposure to the sun, for fear of capillary interchange of the carbonic acid with the 

 gaseous elements of atmospheric air. None such had occurred. From what source, 

 then, came the large amount of nitrogen gas evolved ? the only elements within the 

 matrass were carbon, hydrogen, and oxygen, yet here a large amount of nitrogen was 

 found, which could have come from no other source than the pine leaves. 



429. In this experiment the pine leaves absorbed one measure of carbonic oxide, and 

 gave in exchange for it one measure of nitrogen, and the resulting gas contained, there- 

 fore, half its volume of nitrogen, and half of oxygen, mixed without sensible con- 

 densation. 



430. Hitherto it has often been asserted by chemists, that when vegetable leaves were 

 placed in carbonated water, they absorbed the carbon, and caused the oxygen to be 

 evolved. Vegetable physiologists, botanists, and others, have raised a great many the- 

 ories upon this fact, which, however, a long course of experiments assures me are with- 

 out any foundation. There is no truth in the idea that plants absorb carbonic acid, 

 and assimilate carbon and evolve oxygen. On the contrary, they actually evolve nitro- 

 gen, and the decomposition of carbonic acid, though remotely brought about by the 

 action of the solar ray, is mainly due to the complex play of affinities of the elementary 

 constituents of the plants. 



431. I will here give another example in point, substantiating the same fact under 

 different circumstances. Carbonated water that had been exposed with due care to 

 the sun for two days being provided, 25*75 measures of the resulting gas were taken, 

 and found to contain 1-25 of carbonic acid, for caustic potassa diminished them to 

 24.50. Next, 31-50 measures of hydrogen were added, making in all 56-00, and a pla- 

 tinum ball being introduced, there remained 7-50, indicating 16-16 volumes of oxygen 

 and 8-34 of nitrogen, the composition of the gas being, therefore 



Oxygen 16-16 



Nitrogen 8-34 



Carbonic acid .... 1-25 



25-75 



