table economy, cannot, therefore, be in the least doubted. Nor can 
there exist the least impropriety, in considering these substances, 
as well as phosphorus and sulphur, when thus imbibed, as consti- 
tuting a part of the actual food of plants. 
The subject of the present letter may have been unexpected; 
but be assured, it was necessary to be discussed, before we could 
enter more fully into the peculiar object of our inquiry. A very 
little consideration will shew you, that we should be able to make 
but a trifling progress in an examination into the subsequent 
changes which these bodies undergo, unless we had first ascer- 
tained the substances which had entered into their original com- 
position. 
Yours, &c. 
LETTER IX. 
RESOLUTION OF VEGETABLES INTO THEIR FIRST PRINCIPLES 
FIRST STEP IN THE MINERALIZATION OF VEGETABLES VE- 
GETABLE MOULD IGNIS FATUUS. 
In tracing the transition of vegetable matter into a mineral state, 
it is proper to commence our remarks by an examination of the 
changes which plants undergo, immediately on the extinction of 
vegetable life. 
When from accident, or in consequence of the attainment of the 
full period of maturity, a tree or a forest falls, a resolution of 
