IMPROYIN# tOOR SOILS. 361 



agriculture; but that, when properly mixed, they certainly Obsemtions 

 do support the roots and* add to the growth of plants; and J"^p^"^^^g J^^^ 

 according to the best information on the subject, if taken impiovement 

 generally, the soil, when divided into eight parts, ought *^^^° 

 to consist of the following proportions; — three parts of 

 clay, three of chalk, and two of flint, in the form of 

 sand ; this last admitting of great variation with respect to 

 its fineness or coarsene?s, according to the nature of the 

 climate *. 



Many plausible reasons have been assigned why this 

 admixture of the earths is necessary for the purpose of 

 forming a good soil. First, a soil consisting entirely of 

 clay, would not part with its water sufficiently; chalk 

 would part with it too fast, and flint would not retain it 

 at uU. Secondly, there are many of the plants we wish to 

 cultivate, whose tender fibres are not able to penetrate 

 clay; others that will not be sufiiciently at rest from the 

 loose and changeable nature of sand; and others that can- 

 not act upon chalk +♦ 



If, then, the fertility of soil depend upon the due ad- 

 mixture of the various earths, we may safely infer, that its 

 sterility, or poverty, proceeds from the want of that com- 

 bination. If land be barren when consisting of only one 

 species of earth, its poverty will be in proportion the super- 

 abundance that the soil possesses of that species, let it be 

 flint, clay, or chalk. 



Experimentalists having then agreed, that a due mixture 

 of the earths is necessary to form a fertile soil, and that 

 barrenness proceeds from a want of the proper proportion, 

 we see the necessity of being precise in our description of 

 the soil we call barren. 



* These proportions will differ according to the quantity of 

 rain that commonly falls in any given place. I need not here 

 enter upon the reasons why more rain does fall in one place than 

 another; the fact is indubitilble, and I recommend the placing 

 rain-gages in different parts of the country, in order that, by com- 

 paring the result with the experiments now carrying on in other 

 countries, we may be enabled to say what it the best proportion 

 for this district. 



f See Kifwan, on Manures. 



If 



