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by the earth’s surface from being too soon dissipated, in the same manner as a 
blanket, which may be considered as a sponge filled with air, prevents the 
escape of heat from the person wrapped in it. 
That heat is indispensible towards germination is known to every one. 
During the cold winter, the vessels are closed, the fluids are torpid, and these 
are only to be excited in the proper season when the penetrative sun 
rouses the embryo from its slumber into animated life. But, on the con- 
tary, light is unfavourable, as depriving the seeds of the oxygen, so necessary 
to stimulate its first actions. 
The fine experiments of Scheele and Berthollet have shewn that the ab¬ 
sence or presence of light has a surprising effect upon the result of chemical 
experiments. 
Light disengages oxygen air from the nitric acid, the oxygenated marine 
acid, &c. It reduces the oxyds, or calces of gold, silver, &c. It changes the 
nature of oxygenated muriates, according to the observations of Berthollet. 
Hence it may likewise be supposed to deprive the seed of what rouses 
it into action, namely its oxygen. 
That light impedes germination was first shewn by Dr. Ingenhousz. 
FIRST EXPERIMENT. 
I placed, says this admirable philosopher, in the open air exposed to 
the sun, 60 seeds of mustard, placed equally distant, on an island of cork, 
floating on a glass vessel, full of water, and the sides of the glass were left 
exposed. 
SECOND EXPERIMENT. 
In the second, the apparatus was placed in a window in a room. The 
window shut. 
THIRD EXPERIMENT, 
In a similar apparatus, the glass was covered with black paper. 
