104 ANNUAL REPORT OF NEW-YORK 



solved or diffused in water. The rapidity of their solution is in 

 direct proportion to the extent of their surface. The finer the 

 particles, the more abundantly will the plant be supplied with 

 its necessary nourishment. In the Scioto Valley soils, the water 

 which is transpired by the crops, comes in contact with such an 

 extent of surface that it is able to dissolve the soil-ingredients 

 in as large quantity and as rapidly as the crop requires. In the 

 coarse grained soils, this is not the case. Soluble matters, 

 (manures) must be applied to them by the farmer, or his crops 

 refuse to yield handsomely. 



Again, it is obvious that the finer the particles of the soil, the 

 more space the growing roots have in which to expand themselves, 

 and the more numerously are they able to present their absorbent 

 surfaces to the supplies which the soil contains. 



Other advantages of fine soils will appear in the progress of 

 this essay. 



II. We will discuss the power of the soil to absorb or condense 

 gases or vapors. With regard to this subject we have no actual 

 observations on soils, of any great value. Those we do possess 

 were made forty years ago by Schubler, then a teacher in Fellen- 

 berg's school at Hofwyl in Switzerland, and Avill be presently 

 adduced. 



In the first place may be considered those facts of science which 

 bear upon the question before us. It is found that many solid bodies 

 are able to condense gases upon their surface, or within their pores. 

 Freshly burned box-wood charcoal thus absorbs ninety times its 

 volume of ammonia gas, thirty-five of carbonic acid and nine of 

 oxygen. Copper, iron, lead, platinum, and probably the other 

 metals, also condense gases upon their surfaces. This condensa- 

 tion is scarcely perceptible in plates of solid metal ; but when by 

 chemical means these metals are produced in a very finely divi- 

 ded state, as fine powder or sponge, their surface attraction 

 becomes manifested to an extraordinary degree. There is then, a 

 physical attractive (adhesive) force which is exhibited with greater 

 intensity, the greater the surface of the body possessing it. It is 

 manifested by diff'erent bodies in very unlike degree, and is exer- 

 ted with various energy towards different gases. 



