341 
they weighed 140 grains, and after the saline and 
other matters were driven off by a strong heat, there 
remained 23 grains of pure carbon ; while 460 seeds 
of the same kind, which were submitted to a similar 
process of incineration, afforded much less carbon ; 
so that the seeds in close vessels acquired, says M. 
Braconnot, 1 5 *- grains of pure carbon, which appear- 
ed evidently to have been formed at the expence of 
water, and probably of light*. The air, he adds, 
had undergone little change ; which, doubtless, arose 
from its being so fully exposed to the agency of 
light. 
646. The foregoing result clearly shews that plants 
acquire carbon in air which contains no carbonic 
acid ; but on its absolute correctness we are disposed 
to place but little reliance. The attempts to ascer- 
tain the quantity of carbon in vegetables, by the pro- 
cesses of distillation and combustion, in the manner 
they have been hitherto conducted, appear to us very 
unsatisfactory; for no account seems to have been 
taken of the quantity of that substance which, during 
the operation, passes off in a gaseous form. " When, 
however, a vegetable substance, composed of oxy- 
gen, hydrogen and carbon, united in the form of a 
ternary compound, is submitted to distillation, at a 
temperature not below that of ignition, the equili- 
brium of affinities, which constituted the triple com- 
bination, says Dr Henry, is destroyed ; and the ele- 
ments composing it are united in a new manner. 
Those which are disposed to enter into permanently 
Nicholson's Journal, vol. xviii. p.- 25. 
