Sandsten: INFLUENCE OF GASES AND VAPORS UPON GROWTH. 67 



Ammonia was tried on the same water plants under exactly the 

 same conditions as above. One-tenth of a cc. in 2000 cc. of 

 water, and one-five-hundredth of a cc. in 2000 cc. of water 

 were used, but in both cases both the Sahnnia and Philotrii 

 plants died. 



CONCLUSIONS. 



Influence of Gases. 



From the foregoing tables and records the following conclu- 

 sions seem to be warranted : 



Nitrous oxide. Seeds of Phaseolus multiflorus and Vicia 

 faba will not germinate in an atmosphere containing 80% of 

 nitrous oxide. Seedling of Phaseolus multiflorus and Vicia faba 

 will remain active more than 24 hours in an atmosphere of com- 

 mercial nitrous oxide, but no growth can take place. Shoots 

 exhibit accelerated growth after being kept in an atmosphere of 

 free N ? O or in an atmosphere where the amount of gas ranges 

 from 25 to 100 per cent. No growth in shoots could be detected 

 during the confinement under the bell jars. 



Water plants such as Salvinia natans and Philotria show in- 

 creased growth in solutions saturated with N 2 O. 



Oxygen. Seeds readily germinate in an atmosphere of free 

 oxygen. Seedlings kept in an atmosphere of free oxygen do 

 not grow as rapidly as seedlings in a moist chamber containing 

 ordinary air. Growing shoots kept in an atmosphere contain- 

 ing from 25 to 100 per cent, of free oxygen will remain unal- 

 tered as long as 20 days, but on removal slowly perish. 



Influence of Vapors. 



Ammonia (NOH 4 ). Vapors of this reagent when used in quan- 

 tities not exceeding 1/24000 part are not harmful to the germin- 

 tion of seeds of Phaseolus multiflorus. Seeds exposed for nine 

 days in glass chambers containing from 1/24000 to 1/32000 parts 

 of NOH 4 germinated as freely as the control. The seed of 

 Vicia faba is very susceptible to the influence of this reagent 

 and seeds kept in a glass chamber for nine days containing 

 1/28000 part of NOH 4 failed to germinate. In an atmosphere 

 containing 1/32000 part of NOH 4 90 per cent, of the seed ger- 

 minated. 



Seeds of Phaseolus multiflorus and Vicia faba kept for nine 



