230 GERMINATION OF SEEDS. 



in the open air, and in dry weather, the evaporation from 

 them is rapid, they soon become corrugated, all vital action 

 ceases, and they consequently die. In this manner only can 

 the difference be satisfactorily accounted for ; as it is self- 

 evident that the evaporation must be quicker in the light 

 than the shade, the temperature on account of reflected 

 heat being generally much higher; and I have often seen 

 barley seeds vegetate to a considerable height in the dark, 

 when, if they had been thrown to the light, they would have 

 been soon parched up. 

 Water shows By the results of the above experiments T am well aware, 

 of carbonic 10 " tnat » ^ * ne see ^ s » oe suffered to remain long enough in the 

 acid, and ab- oxigen gas, it at length is all absorbed. This is also easily 

 sorption of shown by placing the jars containing the seeds over water : 

 the carbonic acid gas is then gradually taken up by the wa* 

 ' ter, which ascends in the jar, till no more oxigen gas re- 

 mains. I have sometimes placed large quantities of ger- 

 minating bailey in narrow jars containing from one to three 

 gallons of atmospheric air, and suffered them to remain 

 over water many months. When the remaining air has 

 been tried with the test for oxigen gas, none has been found, 

 nor any trace of any other gas than nitrogen ; and this me- 

 thod may be adopted for procuring this gas for experimen- 

 tal purposes, when not wanted in a hurry. It is certainly 

 too a better eudiometrical way of ascertaining the quantity of 

 oxigen gas in atmospheric air, than that of absorption by- 

 water sometime since suggested. 

 Absorption of I n referring particularly to experiment 15, it will be seen, 

 that the absorption of oxigen gas in eleven hours was ]*60 

 cub. in., being nearly one third of the whole quantity em- 

 ployed. This evidence appears to be irresistible, and is be- 

 yond what I could have reasonably expected. I have already 

 made a few trials to the same purpose in vegetation and re- 

 spiration, and hitherto with similar results, which as soon as 

 concluded I shall take the liberty of laying before you. I 

 shall at the same time make some remarks on fermentation. 

 I remain, 



Dear Sir, yours &c. 



J. ACTON. 



XII. 



