PEAT-BOGS AND PEAT-SWAMPS. 141 



mates, where the condition of humidity is present, immense accumula- 

 tions of peat also occur — not, however, in bogs overgrown with moss 

 and shrubs, but in extensive swamps covered with large trees. 



Composition and Properties of Peat. — Peat is disintegrated and 

 partially decomposed vegetable matter. It is composed of carbon, with 

 small and variable quantities of hydrogen, oxygen, and nitrogen. It is, 

 therefore, vegetable matter which has lost a part of its gaseous con- 

 stituents, and in which, therefore, the carbon is greatly in excess. In 

 more recent peat, the vegetable nature and structure are plainly detect- 

 able by the eye, but in older peat only by the microscope. In all coun- 

 tries where it occurs, it is dried and used as a valuable domestic fuel. 

 By powerful pressure it may be converted into a substance scarcely 

 distinguishable from some varieties of coal, and, thus changed, is now 

 extensively used for all purposes for which coal is used, and has there- 

 fore become an important article of commerce. 



Peat possesses a remarkable antiseptic property. This property is 

 probably due to the presence of humic acid and of hydrocarbons anal- 

 ogous to bitumen, which are formed only when vegetable matter is 

 decomposed in presence of excess of 'water. The bodies of men and 

 animals have been found in bogs in a good state of preservation, which 

 must have been buried many hundred years. In 1747, in ar. English 

 bog, the body of a woman was found, with skin, nails, and hair, almost 

 perfect, and tvith sandals on her feet \ In Ireland, under eleven feet of 

 peat, the body of a man was found clothed in coarse hair-cloth. Several 

 other instances of bodies of men and animals, and innumerable in- 

 stances of skeletons of animals, preserved in bogs where they have per- 

 ished, might be mentioned. Large trunks of trees are often so per- 

 fectly preserved that they are used as timber, and stumps similarly 

 preserved are found with their roots firmly fixed in the under-soil of 

 the bog as if they had grown on the original soil on which the bog was 

 accumulated. 



Mode of Growth. — Plants take the greater portion of their food from 

 the air, and give it, by the annual fall of leaf and finally by their own 

 death, to the soil. Thus is formed the humus or vegetable mold found 

 in all forests. This substance would increase without limit were it not 

 that its decay goes on pari passu with its formation. But in peat-bogs 

 and SAvamps the excess of water, and, still more, the antiseptic property 

 of the peat itself, prevent complete decay. Thus each generation takes 

 from the air and adds to the soil continually and without limit. The 

 soil which is made up entirely of this ancestral accumulation continues 

 to rise higher and higher, until the bog often becomes higher than the 

 surrounding country, and, when swollen by unusual rains, bursts and 

 floods the country with black mud. A bog is therefore composed of 

 the vegetable matter of thousands of generations of plants. It repre- 



