196 Bibliography. 



Geine, in its agricultural sense, is a generic term. It includes all the 

 decomposed organic matter of soils." p. 62. In a chemical sense, he 

 maintains that " the great mass of organic matter of soil is a well de- 

 fined chemical compound termed geine, consisting of carbon, hydro- 

 gen, and oxygen." p. 60. 



Agricultural geine, then, we understand to be the equivalent of the 

 humus and mould of other chemists, and to embrace the extract of 

 mould, the humic acid, humin, crenic and apocrenic acids, and what- 

 ever other compound has resulted from the decomposition of the or- 

 ganic matter of soils. Agriculturally, these may be all regarded as the 

 same thing ; and the farmer may be assured, that " differ as opinions 

 may about its ultimate chemical constitution and the mode of action of 

 geine, whether by being taken up as a solution of geine or geates, or 

 only as a source of carbonic acid, the great practical lesson of all ag- 

 ricultural experience, teaches that geine is essential to the growth and 

 perfection of the seed ; that without geine crops are not raised. Geine 

 is as essential to plants as is food to animals." p. 61. Some of the 

 ablest chemists, as Liebig and Graham, do not admit the distinct exist- 

 ence of crenic and apocrenic acids, enumerated above as compounds 

 found in soils : others regard extract of mould and humin as mere 

 forms of humic acid. But such questions are of little practical agri- 

 cultural importance, and may be safely left to the chemists to settle. 

 Dr. Dana has an opinion on these points, and his chemical geine, as we 

 have seen, is " a well defined compound," embracing the humic acid, 

 the humin and extract of mould of Berzelius, and the sacchulmic acid 

 and sacchulmin of Liebig. Berzelius, it is well known, originally gave 

 the name geine to this compound, in the French edition of his works 

 published in 1832 ; and the same name is retained in Esslinger's French 

 translation of his Traite de Chimie, published in 1840, which lies be- 

 fore us. But very recently, it would seem, he has substituted humic 

 acid for geine ; a mere change of name, but not of opinions respect- 

 ing the nature of the compound. Indeed, the distinct and definite na- 

 ture of this substance seems to be admitted by as high chemical au- 

 thority as almost any organic compound can claim, although the name 

 is not yet settled. 



The ninth principle of agricultural chemistry asserts that " carbonic 

 acid and the carbonates, decompose the earthy, alkaline, and metallic 

 silicates of soils.'''' This is an exceedingly important principle, and 

 applicable especially to the agriculture of primary regions. 



The tenth principle is, that " the base of all salts acts ever the same 

 in agriculture. Peculiarity of action depends on the acid of the salt." 

 This the author regards " in all its length and breadth, as the great 

 practical principle of agricultural chemistry. It opens veins rich in 



