72 AERATION AND AIR-CONTENT. 



estingly, Huber performed all the experiments, while Senebier fur- 

 nished the suggestions and wrote the text. It was seen that seeds 

 would not germinate in air whose oxygen had been exhausted by 

 bees. Peas, beans, lentils, and wheat germinated under water, while 

 many other seeds would not. When the water was deep, the radicle 

 appeared at first, but fermentation ensued and the plants died. 

 Peas began to decompose in 24 hours in water that had been boiled. 

 It is perhaps significant that peas, beans, and spinach alone germi- 

 nated readily under water, and that only a few seeds of other species 

 succeeded in pushing forth the radicle. Carbon dioxid alone was 

 given off at first, but hydrogen appeared with the beginning of 

 fermentation. 



Seeds of lettuce placed in oxygen derived from green plant parts 

 were seen to germinate more rapidly than in ordinary air, as well as 

 to develop their seedlings more rapidly, but the latter were sometimes 

 injured by the gas. In oxygen obtained from manganese the seeds 

 germinated less rapidly. The favorable effect of oxygen drawn from 

 green parts was confirmed by the seeds of wheat, beans, kidney 

 beans, and spinach. Seeds germinated better in a mixture of 3 

 parts of nitrogen or hydrogen and 1 of oxygen than in 3 of the latter 

 with 1 of either of the other two. In 1 to 4 parts of oxygen and 

 hydrogen germination was very good, in 1 to 5 it was slow and the 

 seedlings perished sooner, while in 1 to 7 but five seeds had germi- 

 nated at the end of 3 days and the radicles died immediately. While 

 Lefebure found that the seeds of turnip germinated in nitrogen con- 

 taining one thirty-second part of oxygen, Huber was able to germi- 

 nate lettuce only when the oxygen reached a sixth. Carbon dioxid, 

 when mixed with varying amounts of oxygen, prevented germination 

 in all cases, while some germination took place with all but the 

 minimum amount of oxygen in hydrogen. 



Lettuce seeds refused to germinate in pure nitrogen, regardless of 

 its manner of derivation, but most of them germinated readily 

 when placed again in the air. Peas, however, germinated readily 

 enough in pure nitrogen. With varying mixtures of nitrogen and 

 oxygen, germination did not occur until the one containing 4 times 

 the initial amount of oxygen. The greater number of seeds did not 

 germinate in pure hydrogen, though they grew readily enough in 

 mixtures of it with ordinary air or oxygen. With the latter, growth 

 failed only with the mixture containing the smallest amount of oxy- 

 gen. While peas germinated in hydrogen, lettuce required 7 days 

 instead of 22 hours, and wheat, barley, and oats did not grow at all. 

 All seeds exposed to pure carbon dioxid refused to germinate, and 

 many of them were unable to do so when brought into ordinary 

 air afterward. 



Saussure (1804) found that no germination took place in pure 

 hydrogen, but green plants persisted in it practically as well as in 



