228 PHYSICAL PROPERTIES OF SOIL. 



297. In reference to the electrical relations of 

 soil, the dry sands are non-conductors, the clays 

 weak imperfect conductors, they are in the negative 

 state. Geine is always positive towards the other 

 elements of soil. 



298. In whatever view we regard geine, it is the 

 basis on which rests the whole art of agriculture. It 

 is this which causes the great difference of soil. It 

 is a difference of physical characters. The chem- 

 ical characters are uniform. If then geine is the 

 soul of fertility, if it makes soil, hot, cold, wet, dry, 

 heavy or light, the proportion in which it exists in 

 soil, becomes an agricultural problem of the highest 

 value. This would lead to chemical analysis. The 

 lectures in which the principles set forth in this 

 book, were explained, terminated with a practical 

 exhibition of the process of analysis of soil. Hav- 

 ing already greatly exceeded the limits to which it 

 was intended to confine these pages, the subject of 

 analysis, and several other topics may be resumed at 

 some other time. 



Of these subjects, none is of higher interest, than 

 the origin of salts, whose elements are found in 

 plants, where the soil gives no trace of them. Plants 

 are good analysts, and may detect elements where 

 chemistry cannot ; yet it is difficult to believe, that 

 chlorides can exist as abundantly in soil as their 



