2. “ Whether the exclusion of air from the sensitive plant would be 
harmful to it?” 
3. “ Whether silkworms’ eggs will be hatched in such an exhausted re¬ 
ceiver, in the proper season.” 
“ To which may be added, 
4. “ The trials of putting in a vial full of water, some of those herbs that 
will shoot and grow in water alone, including them in such a receiver, and 
* 
pumping out what air you can, to see whether they will then shoot, or not?” 
“ And though some of these proposals have been formerly begun to be 
experimented, yet ought they to be diligently prosecuted, to see how far the 
air is necessary to vegetation; and whether plants do indeed live as much 
upon the air, as the earth; and the branches of them are rooted, as it were, 
in and quickened by the air, as their roots are planted and nourished in and 
by the earth.” 
“ The experiment heretofore made of this kind was, that some lettice- 
seed being sown upon the earth in the open air; and some of the same seed 
at the same time upon another earth in a glass receiver of the abovemen- 
tioned engine, afterwards exhausted of air; the seed exposed to the air was 
grown up an inch and a half higher, within eight days; but that in the ex¬ 
hausted receiver, not at all: and, air being again admitted into the said 
emptied receiver, to see whether any of the seeds would then come up, that 
in the space of one week they were grown up to the height of two or three 
inches.” 
The great Boerhaave, speaking on this subject, says, “ That the eggs of 
every kind of insect, accurately inclosed in a small glass vessel, however 
exposed to the influence of the sun, do not come forth; and that plants com¬ 
mitted to the ground, and the proper heat administered, if prevented from 
L 
having access to the air, do not vegetate.” 
d he celebrated Spalanzani, repeating the experiments of Boerhaave, found 
indeed that the eggs and seeds did not germinate, when confined in a very 
small quantity of air; and he endeavours to account lor the cciude of this 
Sterility. “ Mons. de Reaumur,” says he, “ took the crysalids of the cabbage 
caterpillar, and put them into glass tubes four or live inches long, which 
