250 PHILOSOPHICAL TRANSACTIONS. [aNNO 1675. 



Some Pneumatical Experiments made in the Air-pump on Plants. By M, Huys:en^ 



and M. Papin. N° 120, p. 477. 



Having passed into the little hole in the top of a receiver a sprig of balm, so 

 that the top of the plant was within the receiver, and the roots without : then 

 closing the rest of the hole with cement, that it might be kept void a good 

 while, the exhausted receiver was then taken away in this manner: the edge of 

 the wide orifice of the receiver was well ground, so that it every where 

 touched exactly a glass-plate, which had also been very smoothly ground to 

 serve for a cover to it, and spreading a piece of lamb's skin wetted over the 

 plate, and thus applying it to the engine, the receiver was set over it : but in 

 one place there was a hail-shot of lead, which kept the receiver from beinff 

 exactly applied to its cover, that so the air might more freely get out : and 

 having afterwards covered all with another large receiver, the pump was plied. 

 All being well exhausted, the engine was shook so as that the little receiver 

 fell off from the hail-shot, and stood every where close to the skin, expanded 

 over the cover of the glass plate. Then suffering the air to re-enter into the 

 great receiver, this air pressing on the small one, kept it so closely fastened to 

 its cover, that it was impossible to sever them. 



Having taken avv^ay the small exhausted receiver, with the plant half shut up 

 in it; the whole was put into a great glass filled with water, with the root down- 

 wards ; then there were formed little water-drops on the leaves that were in 

 vacuo. Being left 10 days in this condition, during that time there were 

 entered about two spoonfuls of water into the receiver, which in all appearance 

 had been pressed through the plant. 



After this, in order to know whether any air had been formed there ; the 

 receiver was replaced on the engine, and having whelmed a larger over it, there 

 was but very little air formed in the small one, because the great receiver was 

 almost exhausted before the air included in the little one could lift it up. Yet at 

 last it did raise it, then inclining the engine to one side, that the small re- 

 ceiver might not be applied to its cover on the air re-entering ; and after this 

 manner both the recipients were filled in the same time. Then observing the 

 leaves of the plant, they were not withered, though they were not grown ; only 

 the leaves had in the middle a little changed their colour, and had a smell some- 

 what sourish ; but the next morning the plant was quite spoiled. It may be 

 believed that the pressure of the air had made the water enter into this plant 

 with such violence, as to have spoiled the leaves in the middle where they were 

 most tender ; though the water still keeping the leaves extended, they withered 



