104 THE CHEMISTRY OF CREATION". 



ployed alone, almost useless for the purposes of 

 vegetation. The principal uses of vegetable 

 mould are to supply a small portion of carbonic 

 acid to the delicate rootlets of young plants, and 

 to restore the different salts and mineral ingre- 

 dients of plants back again to the soil. The 

 inorganic matters necessary to the life of plants 

 are thus given back to the surface ; they consist 

 chiefly of the alkalis, phosphates, silica, sulphur, 

 iron, lime, magnesia, &c. Peat is a soil full of 

 carbon ; and yet, because of the absence of the 

 latter ingredients, peat is the most barren of soils 

 for all ordinary purposes ; in fact, plants potted 

 in pure peat, from which all soluble and in- 

 soluble salts, and other matter, are washed away, 

 will languish and die. The different data upon 

 which this interesting and important conclusion 

 rests, will be found under the chemistry of the 

 atmosphere. 



While such is the process of decay adapted 

 to the production of the vegetable soil, there is 

 a remarkable variety of the same process, which 

 has a most momentous bearing upon the welfare 

 of mankind. This is the decay preceding the 

 formation of coal. In the Mackenzie Eiver we 

 may be said to be permitted to see a modern 

 type of the process, by which, in former times, 

 the formation of this invaluable material was 

 accomplished. Vast quantities of timber are 



