234 > Extradi of a Memoir, and 
nity, the carbonic acid gas would be difengaged, which 
would furnith the means of knowing its inficiériee on the 
‘vegetation. Another box was. filled merely with mould, a 
third merely with charcoal, and a fourth with animal ear- 
‘bon. Thefe were to be anaes ed in comparative experi, 
ments, and barley was fown in them all. 
Though the plants which germinated in the firft box were 
fown in a ftratum of mould about two or three inches in 
thicknefs, they had no refemblance, either in ftrength or co-_ 
lour, to thofe fown in the fecond box filled with mould alone; 
but they had, on the other hand, fuch a perfect refemblance 
to thofe of the third box filled with charcoal, that it would 
have been difficult to diftinguifh the difference. This refem- 
blance continued feveral weeks, after which they feemed to 
have not quite the fame vigour as thofe which grew in the 
charcoal, for which itis not difficult to afign a reafon. The 
enna, oan el himfelf that a _decompofition had really 
taken , becanfe, on exainining the firft bax in autumn, 
he found fin fulphat of Jime had been formed. Thefe ex- 
periments feem proper to conduct to a knowledge ef the man- 
ner in which plants attract the carbonic principle, which all 
the refearches of the aythor demonftrate to be neceffary for 
yigorous vegetation. He proppfes to repeat them on a larger 
fcale, and to vary them as much as poflible*. He repeated, 
feveral times, thofe of M. Humboldt on germination, accele- 
rated by the oxyget rated muriatic acid, and always with fuccefs, 
though with this difference, that this acid did not fayour ve- 
getation fo much as that philofopher afferted. 
M. Rafn fowed barley i in a mixture of mould, fand, and 
quanganefe, in order to fee whether the oxy gen gas would 
* Thele experiments would be more conclufive had net the authoy 
added mould in the boxes into which he put the rubbifh. It is well 
known that mould contains a great quantity of carbon, exactly in the ftate 
wiich renders it fit for the nutrition of vegetables. 
Mi. A. Young. on the other hand, arekte: that plants graw exceedingly 
tll in charcoal: and this oblervation agrees more with the others, and 
with the reafoning, which induces us to believe that carbon muft be dif. 
folved to enter into combination with the other principles of vegetables, 
‘As Pp layts, grow exccedingly well in pure water till a certain period, it 
would appear that they ov ght to ryt equally well m watered a 
tha 7 ) 2 Int 
Sif 
