EARTHS. 



EARTHS. 



tude of instances, which confirms it so far that 

 I am in no doubt that any soil (be it rich or 

 poor) can ever be made too fine by tillage. 

 For it is without dispute, that one cubical foot 

 of this minute powder may have more internal 

 superficies than a thousand cubical feet of the 

 same or any other earth tilled in the common 

 manner: and I believe no two arable earths in 

 the world do exceed one another in their natu- 

 ral riches twenty times; that is, one cubical 

 foot of the richest is not able to produce an 

 equal quantity of vegetables, cateris paribus, to 

 twenty cubical feet of the poorest; therefore, it 

 is not strange that the poorest, when by pul 

 verizing it has obtained one hundred times the 

 internal superficies of the rich untilled land, 

 should exceed it in fertility; or, if a foot of the 

 poorest was made to have twenty times the su- 

 perficies of such rich land, the poorest might 

 produce an equal quantity of vegetables with 

 the rich. Besides, there is another extraor- 

 dinary advantage when a soil has a larger in- 

 ternal superficies in a very little compass, for 

 then the roots of the plants in it are better sup- 

 plied with nourishment, being nearer to them 

 on all sides within reach than they can be 

 where the soil is less fine, as in common til- 

 lage, and the roots in the one must extend much 

 farther than in the other: to reach an equal 

 quantity of nourishment they must range, per- 

 haps, above twenty times more space, to col- 

 lect the same quantity of food. But, in this 

 fine soil, the weak and tender roots have free 

 passage to the utmost of their extent, and have 

 also an easy, due, and equal pressure every- 

 where, as in water." (TuU's New Husbandry, 

 p. 43.) The farmer, too, is aware that when 

 the inert substratum of most cultivated soils 

 is first brought to the surface, it is entirely 

 barren, and that yet, by mere exposure to 

 the atmosphere, it becomes readily produc- 

 tive. 



The comparative rapidity with which soils 

 absorb heat by exposure to the rays of the sun 

 is also a question of much importance. M. 

 Stfhubler found that when the temperature of 

 the upper surface of the earth was 77 in the 

 shade, earth, &c., exposed to the sun in ves- 

 sels four inches square and half an inch deep, 

 from eleven till three o'clock, attained the sub- 

 joined temperature : 



As different soils absorb heat with varying 

 rapidity, so they retain it with more or less 

 tenacity, as displayed in the following table 

 by Professor Schubler :- 



From these experiments, the farmer will 

 perceive that the popular ideas, with regard to 

 the quality of soils when they are denominated 

 hot and cold, are nearly accurate. He will see 

 that sandy soils absorb the heat of the sun 

 faster than any others, but then their ra;e of 

 cooling is equally great ; more rapid in their 

 transitions from heat to cold than any others, 

 the crops which they produce are commonly 

 thin; and to these rapid transitions we may 

 assign one reason for the poverty of the pro- 

 duce. The clays, on the contrary, which im- 

 bibe the sun's rays more slowly, retain their 

 heat much longer. 



There are several other properties of the 

 earths with which it is highly desirable that 

 the cultivator should be acquainted: thus, the 

 resistance which soils offer to the plough or the 

 spade, in their wet and dry state, is a question 

 on several accounts highly interesting to the 

 farmer. This property of the soil has also 

 been examined by Professor Schubler, and the 

 result of his experiments will be found in the 

 following table : 



From these laborious researches of the che- 

 mical philosopher the intelligent farmer may 

 derive many new and important conclusions 

 witlj regard to the improved cultivation of the 

 earth. They may serve to explain to him one 

 great reason why fallowing and pulverizing 

 the soil, either by machinery or by the mixture 

 of chalk or sand with the heavier clay soils, 

 promotes so decidedly, or so permanently, their 

 fertility. And, again, the advocate for all old 

 customs and obsolete modes of tillage may 

 lence, among other things, learn why it is tha't 

 deep ploughing, either by the common or by 



435 



