132 NORTH UIST. PEAT. 



compounded principally of hydrogen and carbon. Now if 

 peat be subjected to the same process we obtain the same 

 results but in different proportions. The acetic acid is 

 diminished and the oil bears a smaller proportion to the 

 charcoal, that proportion diminishing gradually according 

 to the perfection of the peat. Consequently the chief 

 effect of increasing decomposition in the peat is to diminish 

 the proportion of the hydrogen to the carbon in the 

 vegetable compound, of which these are the principal con- 

 stituents. The effect of water on the vegetable fibre is 

 therefore similar to that of fire, although less perfect; since, 

 after the last efforts of the former substance, a considerable 

 portion of hydrogen remains combined with the carbon ; 

 even in the lignites, of which the changes are more com- 

 plete than those of any peat with which we are acquainted. 

 In the incipient stage of the action of fire, the compound of 

 carbon and hydrogen is partially soluble in water, a familiar 

 example of which occurs in the roasting of coffee, and the 

 same takes place in the conversion of vegetables into peat. 

 In each case when the proportions of these two constituents 

 have attained a certain ratio the compound is no longer 

 soluble. 



The simple principles thus laid down seem to contain 

 every thing requisite to explain the chemical nature of 

 this substance, and I shall not therefore pursue them 

 further. They will serve to unravel and reconcile many 

 obscure and contradictory experiments, and in pointing- 

 out the causes of the varieties of peat, assist agriculturists 

 in their pursuits by directing their attention to the essen- 

 tial differences.* 



I have had occasion to observe in the island now under 



* It must be obvious, that the conversion of peat into soil will be dif- 

 ficult in proportion to its perfection; since independently of its greater 

 compactness, it approaches more nearly to the stale of charcoal, bearing, 

 to imperfect poat, un analog) 1 resembling that which effete does to recent 

 manure. Hence also a hint may be derived respecting the conduct of that 

 process by which the manure called the Moadmvbank compost is formed. 



