58 On the Use of Green Vitriol of Iron, 



are not of themselves at all or necessarily nutritious, but 

 contribute to render other things nutritious bv excitinc; the 

 action of the stomach and other organs of digestion and as- 

 similation. 1 have no doubt of the truth of the proposi- 

 tion, that no living thina:, neither plant nor animal, can 

 grow and live in a state oF visible action without constant 

 supplies of matter which has been alive ; in other words, 

 living animals and vegetables can only live on doiid animals 

 and dead vegetables. No plant nor animal has ever beca 

 known by experience, nor in the nature of things does it 

 iecm reasonable, that they can be nourished by n)cre water 

 anil pure air, as some persons have asserted. 



I shall make a very few renjarks on the other two sub- 

 stances which are the subject of Mr. Willaume's letter. 



2. The Peat. 



The peat is a dense mass of vegetable matter for a certain 

 depth, parti v in a dead and partly in a living state, with 

 which is mixed more or less earth, and in burning it afibid;? 

 so nmch empyreumatic oil as to give a disagreeable taste to 

 roasted provisions; hence, as we are told, it has been re- 

 jected from the kitchen. This fuel affords a vast quantity 

 of what the chemists call ligiiic add; hence it is rejected 

 also from the parlour, as very destructive to the grates, i 

 beg to suggest that this lignie acid might be saved in burn- 

 ing the peat as fuel, and be used for various purposes in 

 manufactures ; and the charred peat may be used ui place 

 of charcoal of wood. Probably, too, other useful products 

 will be found, on examining the matters more accurately 

 which are afforded by distillation. 



3. J.ihes. 



If the peat were mere vegetable matter, the ashes afforded 

 by it would be as trifling as those of wood ; but some parth 

 of the moor contain so much earth and oxide of iron as 

 to leave behind, on burning, a considerable quantity of in- 

 combustible n)atter ; and such kind of peat, we are told, is 

 not used as fuel ; but, after burning, the residuary matter 

 is an efficacious manure, much more so than is conmionly 

 afforded by paring and burning. The ashes are more red 

 and more fertilizing than ashes of common turf, because 

 they contain more iron. 



The spontaneous springing up of white clover, in land 



manured with these ashes, is similar to the spontaneous 



oTOwth of this plant on heath land which has been covered 



with lime to destroy all its pvo;?ent vcgetuliun ; and this fact 



1 shows 



