No. 105.J ■ 427 



wood and even animal substances remain in it undecayed for a long 

 time, animal bodies being not unfrequently found converted into a 

 kind of hard fatty substance, called adipocire. This takes place only 

 when the peat is completely saturated with water, so as to prevent 

 the access of atmospheric air. 



The products of vegetable decomposition under water, differ essen- 

 tially from those arising from exposure to the air, as before observed, 

 and the changes which take place in a bog by draining and plowing 

 it, are more complicated than many imagine. 



It contains, according to my analysis, crenic acid, mostly combin- 

 ed with lime, magnesia, alumina and oxide of iron ; apocrenic acid ; 

 humic acid ; humin, and ulmin, the latter being found in brown peat ; 

 extract of humus, consisting of two distinct substances ; vegetable 

 fibre, disorganized in part; phosphoric acid, combined with the earthy 

 bases ; sulphuric acid, combined with alumina and with oxide of iron 5. 

 oxide of manganese ; also a little potash and soda, sea salt and silica. 



There are, probably, other organic acids in some kinds of peat, but 

 the above mentioned are those which are generally present. 



When peat is exposed to the air, it blackens, and evidently under- 

 goes a change in its composition, a large proportion of apocrenic 

 acid being produced by the action of the atriiosphere ; a change ana- 

 logous to that which takes place when yellow subsoil is exposed to 

 the action of the air, and becomes black mould. 



Peat always contains nitrogen, and will give out ammonia by the 

 action of hydrate of potash, when treated by Will and Varrentrapp's 

 method. This is owing to the presence of the highly nitrogenized 

 apocrenic and the crenic acids, which are present in all the peats I 

 have analyzed. 



This principle is one of considerable practical importance; since as I 

 shall demonstrate, these acids play an important part as fertilizing 

 agents, and are readily convertible into other substances which enter 

 into the composition of plants. 



Peat also contains a sirsall proportion of phosphate of lim-e, a saline 

 ingredient which enters into the composition of cereal grains in large 

 proportions, and is one of the constant ingredients of all plants that 

 have been analyzed. Phosphate of magnesia is also present in sev- 

 eral kinds of swamp muck and peat, and is also an important salt re- 

 quired by all plants. 



It is well known that when recent peat i& spread freely on soil, it 

 generally acts unfavorably on vegetation, and the farmer justly says 

 it is sour and worthless in that state. This acidity will be recogniz- 

 ed by those who have seen the stones thrown out from bogs ; for all 

 those matters which acid would attack and dissolve, are found to 

 have been removed, every trace of felspar and mica are found to be 

 dissolved from a piece of granite, and a white silicious skeleton of 

 the stone remains. All the oxide of iron is generally taken up also, 

 unless, as is sometimes the case, the bog is already saturated with it. 



Sulphate of iron and sulphate of alumina, not unfrequently, are 

 also present in excess^ and exert a baneful action on plants. 



These facts will serve to explain why peat should be operated 



