Sandsten : INFLUENCE OF GASES AND VAPORS UPON GROWTH. 61 



TAI5LE IV. 



I. 25 per cent, of gas in 4000 cc. of air. 

 II. 50 per cent, of gas in 4000 cc. of air. 



III. One atmosphere of free gas. 



IV. Control. 



a. Nitrous oxide. 



b. Oxygen. 



In the above table the plants treated with nitrous oxide show 

 a marked increase in vigor and flowering capacity. The leaves 

 were of a dark green color and very large. The leaf petioles 

 were somewhat shortened, giving the plants a stocky appear- 

 ance. The root systems of the plants treated with nitrous ox- 

 ide were very strong. All evidence seems to point to the con- 

 clusion that the treatment was beneficial to the plants. The 

 oxygen also appeared to be beneficial to the plants when used 

 in quantities not exceeding 50 per cent. In an atmosphere of 

 free oxygen the plants showed no deviation from the normal 

 while in the gas, but upon the removal of the bell jar the plants 

 soon began to show signs of decay. The plants treated with 

 oxygen exhibited a marked elongation of the petioles. 



B. Vapors. Ammonia and chloroform were used in these 

 experiments in the following quantities : i/ioooo, 1/15000 and 

 i 40000 parts. The capacity of the bell jars was 7500 cc. The 

 reagents were introduced in an aqueous solution of 100 cc. The 

 plants were kept under the bell jars for 26 hours. Upon exam- 

 ination it was found that the plants which had been subjected 

 to the influence of i/ioooo part of ammonia or chloroform vapors 



