Ingen-Housz • Excerpts from Experiments upon vegetables 97 



the close of the day, and ceases entirely the contrary is apt to contaminate it. 

 at sun-set, except in a few plants, which All plants possess a power of cor- 

 continue this duty somewhat longer recting, in a few hours, foul air unfit for 

 than others; that this office is not per- respiration; but only in clear light, or 

 formed by the whole plant, but only in the sun-shine. This remarkable prop- 

 by the leaves and the green stalks that erty of plants is indeed very great; for 

 support them; that acrid, ill-scented in a few hours, nay even sometimes in 

 and even the most poisonous plants an hour and a half, they purify so much 

 perform this office in common with the a body of air quite unfit for respiration, 

 mildest and the most salutar\'; that the as to be equal in goodness to atmos- 

 most part of leaves pour out the great- pheric air. They will even do it when 

 est quantity of this dephlogisticated air enclosed in a glass vessel, without any 

 from their under surface, principally water. One leaf of a vine, shut up in an 

 those of lofty trees; that young leaves, ounce phial, full of air fouled by breath- 

 not vet come to their full perfection, ing so that a candle could not bum in 

 yield dephlogisticated air less in quan- it, restored this air to the goodness of 

 titv, and of an inferior quality, than common air in the space of an hour 

 what is produced by full-grown and old and a half. But plants enjoy this privi- 

 leaves; that some jDlants elaborate de- ledge only in the day-time, and when 

 phlogisticatcd air better than others; they grow in unshaded places, 

 that some of the aquatic plants seem This power of plants extends itself 

 to excel in this operation; that all even to the worst of all airs, in which 

 plants contaminate the surrounding air an animal finds his destruction in a 

 bv night, and even in the day-time in moment, such as is pure inflammable 

 shaded places; that, however, some of and highly phlogisticatcd air, which is 

 those which are inferior to none in little or scarcely at all diminishable by 

 yielding beneficial air in the sun-shine, nitrous air. I obser\'e some difference in 

 surpass others in the power of infecting various kinds of plants in this respect, 

 the circumambient air in the dark, even and found that water plants seem to 

 to such a degree, that in a few hours possess this quality in a greater degree 

 they render a great body of good air so than others. 



noxious, that an animal placed in it Experiments: A sprig of pepper- 

 loses its life in a few seconds; that all mint put in a jar full of air fouled by 

 flowers render the surrounding air breathing (so as to extinguish a can- 

 highlv noxious, equally by night and die), and exposed to the sun, had cor- 

 bv dav; that the roots removed from rected this air in three hours so far 

 the ground do the same, some few, that a candle could bum in it. 

 however excepted; but that in general A sprig of nettle was put in a jar 

 fruits have the same deleterious quality full of air fouled by breathing so as to 

 at all times, though principally in the extinguish a candle, it was placed in a 

 dark, and many to such an astonishing room during the whole night, next 

 degree, that even some of those fruits morning the air was found as bad as 

 which are the most delicious, as, for in- before. The jar was put at nine in the 

 stance, peaches, contaminate so much morning in the sun-shine; in the space 

 the common air as would endanger us of two hours the air was so much cor- 

 to lose our lives, if we were shut up in rected, that it was found to be nearly 

 a room in which a great deal of such as good as common air. 

 fruits are stored up; that the sun by A sprig of Persicaria mens was put 

 itself has no power to mend air with- in a vial full of air fouled by breathing, 

 out the concurrence of plants, but on so as not to allow a candle to burn in it; 



