Experiments on Vegetation, 43 
to Nature, in order to determine what were the real effects of 
vegetation and vegetables on the atmosphere. 
As germination is the first process of vegetation, I shall com- 
mence by calling your attention to the effects of that part of the 
physiology of vegetation on the air of the atmosphere. 
Exp.\. For this purpose I placed a number of peas, barley, 
&c. to germinate in a given portion of atmospherical air in a 
glass receiver (the mouth of which was confined by mercury, ina 
groove turned in a slab of beech-wood. My reason for this me- 
thod was to avoid the action of water on the air of the receiver, 
as well as to prevent a large portion of mercury being exposed 
to the same. The upper part of the receiver was furnished with 
a cock, to which | could attach a syringe, and draw out a por- 
tion of air to be examined, without disturbing the apparatus; to 
which also a funnel was ovcasionally attached, to supply water 
to the plant when necessary), 
After a short time I found germination stop; but on 1 lifting 
up the receiver so as to allow some air to escape and fresh air 
to enter, germination again commenced: this I repeated several 
times with similar results. Finding that germination ceased 
when seed was so confined, I had no doubt but that some altera- 
tion must have. been produced on that fluid in which they had 
been inclosed.. My next inquiry was to ascertain what this al- 
teration was: for which purpose I agitated the air with lime- 
water. A considerable turbidness was the result; 1-13th was 
absorbed, and 4 inches of it with 2 in. of nitrous gas occupied 
4°4 in.—but 4 in. of common air and 2in. nitrous air occupied 
only 3°9 in. ; from which we see that there was an abstraction of 
oxygen from the air of the receiver and a formation of carbonic 
acid gas,—most likely the oxygen of the atmosphere united 
with the carbon of the seed and produced the carbonic acid gas. 
Exp. II. I placed a portion of barley to germinate in a similar 
manner; and when germination appeared | to cease, | examined 
the air. To 2 in, I put 1 in. of nitrous gas, which occupied 3 in., 
so that no diminution whatever took place; consequently the 
whole of the oxygen had disappeared and formed some combi - 
nation; at the same time 2 in. of atmospherical and | in. nitreus 
air occupied only 1:8 in. 
Exp. 11. August 10,1816. Twosmall scarlet beans growing 
in a pot, and exposed to the sznshine, were bent under a re- 
ceiver and confined by mercury. At the expiration of seven days 
2 in. of the air and | in. of nitrous gas equalled 1°45 in. ; but 
the above quantities of atmospherical air and nitrous gas equalled 
1:42 in., consequently this process of vegetation had somewhat 
injured the air by abstracting its oxygen. 
eeep IV, June 4, 1816. An entire turf composed of Dutch 
clover 
