ORGANIC AGENCIES. 85 



tion iiml the undecomposed remains of the recently dead. 

 As wo pass down, the remains become older, and there- 

 fore more and more decomposed, and darker in color, 

 until, at sufficient depth, it is a black mud, structureless 

 to the naked eye, though still revealing vegetable struc- 

 ture to the microscope. In composition it is mainly car- 

 bon, with variable proportions of the hydrogen, oxygen, 

 and nitrogen of the original plants. It is a disintegrated 

 vegetable matter, which has lost much of its gaseous 

 elements, and therefore with an excess of carbon. It is 

 therefore a good fuel, and is extensively cut and used for 

 this purpose, either simply dried or, better, made into a 

 cake by hydraulic pressure. 



Antiseptic Property. Peat has a remarkable power 

 of preventing or retarding decomposition. Logs and 

 stumps have been found buried fifteen to twenty feet in 

 peat, and therefore probably hundreds and even thousands 

 of years old, which are still in a sound condition, and 

 even fit for timber. Bodies of men and animals have been 

 found with even the flesh preserved, though changed into 

 adipocere. According to Lyell, the body of a man, 

 ctotftecTln coarse hair-cloth, was found in an Irish bog ; 

 and in a bog in Lincolnshire, the body of a woman, with 

 skin, nails, and hair preserved, and with sandals on the 

 feet. The skeletons of men and animals thus preserved 

 are much more common ; and even the skeletons of extinct 

 species have been found in a perfect condition and un- 

 petrified. The finest specimens of the mastodon have 

 been obtained from old bogs in New York, New Jersey, 

 Ohio, and Missouri. 



Mode of Accumulation. Eemembering the antiseptic 

 property of peat, its mode of accumulation is easily under- 

 stood. In forests, a layer of mold a few inches thick ac- 

 cumulates on the soil from decomposition of the annual 

 leaf-fall. This will not thicken indefinitely, because the 

 rate of complete decomposition quickly equals the rate of 



