325 
experiment was repeated, and afforded the same re- 
sults. 
625. We next varied the experiment, by mixing 
together equal quantities of the residual air in which 
beans had grown, and of oxygen gas obtained from 
oxide of manganese. Both the gases were first wash- 
ed separately in lime-water, and were contained in a 
jar of the capacity of about 37 cubic inches. A small 
egg-cup, holding a cubic inch of the water of potassa, 
and covered with a piece of oiled cloth to prevent 
the entrance of water, was next passed under water 
into the jar ; and the oiled cloth was immediately 
withdrawn. The jar with the alkaline solution was 
next removed from the trough on a saucer conveyed 
beneath it. By the tenth day, the volume of air had 
somewhat diminished, and the jar being now raised, 
the alkaline solution was passed into a tube filled with 
mercury, and inverted in a bason of that fluid. Di- 
luted acid was next passed up into the tube, which 
excited effervescence in the solution, and produced 
the disengagement of about T^th of a cubic inch of 
gas, which was afterwards attracted, with the usual 
phenomena, by lime-water. In these experiments, 
the carbonic acid could have been formed only by 
the union of the oxygen gas with the carbon which 
had previously combined with the nitrogen of the at- 
mosphere during the process of germination ; and 
the results, therefore, accord completely with those 
obtained by M. Huber. 
626. This expulsion or emission of carbon by seeds 
is farther confirmed by the experience of M. Sene- 
bier, who observed similar phenomena to occur in the 
