Experiments on Plants 787 



2. Vegetation. 



I made also a few attempts to obtain effects on vegetation prop- 

 erly so-called. 



Experiment CCCLVII. June 15. Barley. 



Seeds of barley in the same quantity sown in three similar pots, 

 full of earth; all left under similar conditions. 



June 25. All three sowings have sprouted, but rather unevenly; 

 in the first, the sprouts measure on the average 14 cm.; in the second, 

 15 cm.; in the third, 16 to 17. 



They are placed under three bells. 



A. The least satisfactory sowing; left at normal pressure. 



B. The intermediate sowing; taken to a pressure of 50 cm. 



C. The best; taken to 25 cm. 



June 27. The three sowings have kept their original differences. 

 July 3. Same result. 



Experiment CCCLVIII. July 24. Sensitive plants of the same 

 sowing; one in each pot, about 10 cm. high. 



A. 4 pots under a bell of 3.5 liters at normal pressure. 



B. 4 pots under a bell of 7.1 liters; brought to a pressure of 50 cm. 



C. 4 pots under a bell of 11 liters; brought to a pressure of 

 25 cm. 



All are set on plates full of well-moistened earth, and are placed 

 in sufficient light. 



The pressure is lowered carefully; the folioles closed when the 

 pressure had been lowered about 20 cm., then opened again later. 



In the evening, C closes its folioles much later than the other two. 



July 25. Air has leaked into C; the pressure is about 40 cm. It 

 is lowered to 25 cm. Some folioles and even some leaves are already 

 falling; one or two sensitive plants seem dead. 



B. Rather sickly. 



A. In good shape. 



July 26. C. The pressure has risen to about 45 cm.; nevertheless 

 the sensitive plants are all dead. 



B. All sickly, some dead. 



A. In very good shape; they are growing. 

 July 27. B. All dead. 

 A. In good shape. 



Experiment CCCLIX. August 1. Sensitive plants like those of 

 the preceding experiment. Two in each bell. 



A. Taken to a pressure of 60 cm. 



B. Taken to a pressure of 50 cm. 



C. Taken to a pressure of 25 cm. 



August 3. A few folioles and leaves fall in C. 



August 6. 3 o'clock. A. Folioles sensitive and open; B. Half- 

 closed or not very sensitive; C. Completely closed. 



August 7. Brought back to normal pressure. 



All are sensitive; C. Much less than the others; C does not close 

 well in the evening. 



August 9. A. In good shape; very sensitive; B. Not very sensitive; 

 sickly; yellowish; C. Leaves are falling; dying. 



