29 6 Nutrition of Vegetables . 
contained in the seeds from which they sprung ; while those in 
mould were much more vigorous, in consequence of the carbon 
with which it furnished their roots. But these experiments were 
on too small a scale to furnish satisfactory results ; and I have 
therefore attempted to investigate the subject anew, in order to 
ascertain, how far this opinion is well founded. 
As a preliminary step, I conceived it necessary to analyse vege- 
table mould in a state of perfect decomposition. For this purpose 
I selected perfectly pure, black, pulverulent mould, from among 
the hollow roots of a very old tree. Distilled water, in which 
it was boiled, remained colourless after filtration, and on being 
evaporated left no sign of any soluble matter. 
A hundred grammes [31 oz.] were reduced by dessication to 
20, which shows it to be extremely retentive of water. 
These 20 gr. distilled at a red heat, gave out 4 of water, that 
powerfully reddened infusion of litmus ; and contained empyreu- 
matic acetous acid, partly saturated with ammonia; 2 of an acrid 
oil, that congealed on cooling, and was of a dark brown colour; 
89 cubic inches of oily hydrogen gas, burning with a blue flame; 
and 34 cubic inches of carbonic acid absorbed by lime. 
The coally residuum weighed 8*5 grammes, which were re- 
duced by incineration to 2*4 gr. of light yellow ashes. 
Boiling distilled water digested on these ashes acquired no 
peculiar taste, did not turn syrup of violets green, and was bare- 
ly rendered turbid by the addition of a few drops of oxalic acid, 
which seemed to indicate, that a few particles of lime had been 
set free by the calcination. The nitrates of barytes and of silver 
produced no change in it. On farther analysis these ashes afford- 
ed 1*3 of a gr. of silex, *2 of oxyde of iron containing a little ox* 
yde of manganese, *25 of phosphate of lime, *2 of lime, and some 
traces of magnesia. 
I boiled 6 gr. [92 grains] of the same mould for an hour, in a 
strong solution of caustic potash, when it became glutinous, and 
swelled up I then diluted it with water filtered, and obtained a ij 
very deep brown liquor. This mixed with the lixiviating wa« 1 
ters gave on the addition of an acid a precipitate, that weighed 
1 gr. when dried. It was of a very black colour, and in little :( 
shining scales. Scarcely any vapour arose from it when thrown | 
on burning coals, and I consider it as charcoal well saturated with 
hydrogen Art may imitate this substance, by effecting by fire :j 
what nature does by time. If we deprive a vegetable substance 
