PEAT AND ITS USES 37 



absence of air the bacterial activity is checked, and 

 complete resolution of the plant debris to its simplest 

 constituents is arrested. In the process some of 

 the carbon has disappeared in the form of carbon 

 dioxide or marsh gas, while much has been left behind 

 in the form of humic acid and other relatively com- 

 plex products, the composition of the mixture 

 depending on the original constituents of the moss, 

 on the bacteria and fungi that have acted on it, and on 

 the atmospheric and other conditions in which they 

 have done their work. The latest materials to be 

 altered are the woody plant tissues, but as the peaty 

 deposit gets covered and subjected to pressure as a 

 result, for instance, of the slow local sinking of the 

 earth's crust, atmospheric air becomes completely 

 excluded, fermentation sets in, the oxygen combined 

 with the tissues tends more and more to disappear, 

 and the moss then goes through the changes, be- 

 coming first peat, then, under the influence of time 

 pressure, and further bacterial action, lignite, and, 

 lastly, as the pressure further increases, coal. So 

 much at the present stage for the composition of 

 peat, a subject to which I shall have to return in the 

 chapter on the humus of the soil. 



That the problem of the utilization of peat is an 

 important one to the world is shown conspicuously 

 by a glance at the extent of the deposits present in 

 various parts of the world. In Europe there are 

 believed to be 212,700 square miles of bog ; in Canada 

 50,000 square miles; in the United States of America 

 35,000 square miles; in European and Asiatic Russia 

 70,000 square miles. Northern Europe alone is esti- 



