CALCAREOUS MANURES— APPENDIX. jgg 



to apotheme, which makes part of the mould. The salts of acids of mineral 

 origin are preserved, unless they are soluble, in which case the rain car- 

 ries them off. In addition, mould contains a substance but slightly soluble 

 in water, which colors the liquid yellow, and a carbonaceous substance 

 which is entirely insoluble, and which appears to be one of the products of 

 a destruction, still more advanced, of organic matters. 



To give an example of a completed formation of a mould of vegetable 

 origin, I shall here state the results of an analysis to which Braconnot sub- 

 mitted some wheat, which had remained during many centuries in a damp 

 vault, the issues from which vvere stopped up by earth, and of which the 

 existence was forgotten, until by chance it was again discovered. The 

 grains had preserved their form, and the brightness of their outside skin ; 

 but they were black, and were reduced by the slightest pressure to a black 

 powder. The water with which they were boiled was colored yellow, and 

 it left, after being evaporated, a saline mass of a brownish yellow, which 

 burnt with slight explosion when heated, and which, besides the substance 

 cited soluble in water, contained nitrate of potash, nitrate of lime, and a 

 little of the muriates of potash and of lime. The nitrates were the result 

 of the oxidation of the nitrogen contained in the gluten and vegetable 

 albumen, and of the combination of the nitric acid thus produced, with the 

 bases previously combined with vegetable acids. The weight of this mass 

 soluble in water, including tlie salts and all the other principles, did not 

 exceed H per cent, of the weight of the black grain. When the part in- 

 soluble in water was boiled in alcohol, a small trace of a brown substance 

 was taken up, which remained after evaporating the alcohol, and had the 

 consistence of wax. The mass, exhausted of its soluble parts by boiling 

 water and alcohol, was then heated slowly with a weak solution of caustic 

 potash, which became saturated and colored of a blackish brown ; and this 

 treatment was continued as long as new potash lie took up any thing. 

 This substance was precipitated from the solution by an acid ; it was the 

 body similar to apotheme which has already been mentioned, and of which 

 the weight amounted to 261 per cent. The portion of matter insoluble in 

 the alkali preserved the same appearance. This, exposed to the action of 

 diluted muriatic acid, yielded to it a certain quantity of lime, of oxide of 

 iron, and of phospliate of lime. The residue was again acted on by potash, 

 which took up a new and very large proportion of the body similar to 

 apotheme. This was after that combined with lime, and resisted in that 

 state the action of potash. This calcareous combination amounted to 42 

 hundredths. The 30 per cent, remaining consisted of a black carbona- 

 ceous matter, insoluble in the solvent used. 



If cultivated soil is treated in the same manner, similar results will be 

 obtained, with this difference, that the earthy matter of the soil is found 

 mixed with the products which are obtained, whilst no soluble salts are 

 met with, they being generally carried off by the rains. 



To describe the constituent principles of mould, it is necessary to desig- 

 nate them by particular names. I will then call extract of mould the body 

 soluble in water, and I will give the name of geine* to the matter similar 

 to apotheme, which constitutes the principal mass of mould. As to the 

 coally substance insoluble in water, alcohol, acids and alkalies, I will desig- 

 nate it by the name of carbonaceous mould. 



Extract of mould.— We obtain this substance by drawing it from the 

 mould by the action of cold water, which becomes thereby colored yellow, 

 and which leaves, after evaporation, a yellow extract of a bitter taste, and 



* Or humin, as termed by other authors. 



