346 PEAT. 



which is not obvious, or does not belong to the general 

 principles of agriculture. 



On, the Chemical Nature of Peat, Lignite, and Coal. 



Having given the reasons for uniting what could not 

 have been separated without inconvenience, I must 

 commence with the first of these kindred substances. 

 The brown colour of mountain streams proves that 

 peat contains an ingredient soluble in water, though 

 small in quantity ; as it is formed also, only in the inci- 

 pient stage of the process. Perfect peat communicates 

 no stain to cold water, and but a slight one at the boil- 

 ing heat. Having already questioned the imaginary 

 antiseptic power of peat water, I may remark that the 

 small quantity of tannin occasionally present is the 

 produce of Tormentilla or other plants, and that when 

 an acid does exist, it is the acetic, generated during 

 the formation of the hydrocarbonaceous compound, 

 just as it is in the process of roasting, or incipient car- 

 bonization. And if animal bodies have sometimes 

 been preserved in peat bogs, it has not been enquired 

 whether the soft parts were not converted into adipo- 

 cire, as the effect of water merely ; as is probably the fact. 



On this soluble matter I must premise, that when 

 vegetable substances are exposed to heat, the carbon 

 and hydrogen, with some portion of the oxygen, and 

 also of the azote, produce new combinations, under 

 different proportions, which are partially soluble in 

 water ; as is familiar in the case of sugar, malt, and 

 coffee ; while acetic acid, holding some of this com- 

 pound in solution, is also generated. Now the action 

 of water is similar, though tedious : yet rapid in such a 

 case as that of manure, compared to vegetables pro- 

 ducing peat: while here also there are produced a so- 

 luble and an insoluble compound ; the latter being 



