Experiments on Plants 793 



carbonic acid, was introduced and complicated the results. That 

 is why I did not make more experiments by this method, in which 

 it is quite difficult to renew sufficiently an air with low oxygen 

 content. 



B. Normal Pressure: Superoxygenated Air. 

 I now come to the more numerous and much more conclusive 

 experiments conducted by the second method. 



Experiment CCCLXXV. July 12. Barley sown on wet paper; 20 

 seeds. 



A. Bell of 7 liters; air containing 65% of oxygen, which cor- 

 responds to 3 atmospheres of air. 



B. Bell of 13 liters; ordinary air. 



July 18. A, the shoots are 8 cm. high; those in B, 12 cm. 

 July 22. A, an average of 15 cm.; B, an average of 21 cm. 



Experiment CCCLXXV I: November 4. Sowings of barley and 

 cress on wet paper. 



A. Air with 79% of oxygen, equivalent to about 4 atmospheres 

 of air. 



B. Ordinary air. 



November 7. A few seeds germinating in B. 



November 9. A few seeds germinating in A. 



November 25. A. Only two barley seeds have sprouted, and 

 measure 4 cm.; the cress is about 2 cm.; none of the shoots are very 

 green. 



B. All the seeds have germinated and are very green; the cress 

 is about 2 cm. high, the barley 12 cm. 



Experiment CCCLXXVII. December 7. Twenty seeds of barley 

 and cress on wet paper. Bells of 2 to 3 liters. 



A, in air with 65% of oxygen. 



B, in air with 40% of oxygen. 



C, in air with 31% of oxygen. 



D, in ordinary air. 



December 17. The cress has sprouted in all quite equally. The 

 barley is sending out radicles in all. 



January 1. A. The barley shoots are 9 cm. high, the stalks are 

 half open, slender, not many; the cress is 2 cm. high; not all of the 

 seeds have germinated. 



B. Barley 12 cm., stalks green; cress 2 cm. 



C. Barley 13 cm., stalks slender, but closed; cress 3 cm. 



D. Barley 10 cm., stalks thick, unfolded, green; cress 2 cm., thick, 

 very green. 



January 14. A. Barley 11 cm., stalks faded, slender, scanty; 

 cress 2 cm. 



B. Barley 14 cm., stalks green, unfolded; cress. 3 cm. 



C. Barley 16 cm., stalks long, slender, folded; cress 4 cm. 



D. Barley 13 cm., leaves open, very green; cress 3 cm. 



