no CHYMISTRY APPLIED TO AGRICULTURE. 



this evil resulting from a second freezing, that 1 propose 

 levelling the earth by the roller, after the first thaw. 



These defects, more marked in argillaceous soils than 

 in others, require to be amended ; every thing which will 

 tend to soften the earth, to render it more light and po- 

 rous, and to facilitate the passage of water through it, is 

 perfectly adapted to this kind of soil : thus the mixture of 

 earths, and of calcareous sands, broken shells, chalks, and 

 lean marl ; deep and frequent ploughing ; the turning in of 

 green crops ; the use of hot manures, such as the dung, 

 fresh from the barn-yard, of sheep and horses, that of 

 pigeons and fowls, poudrette^ and the salts, are so many 

 means which may be made to concur in the improvement 

 of argillaceous soils. 



T have had opportunities of seeing many soils possessing 

 the same faults as the argillaceous, but not owing to the 

 excess of that earth ; for by mixing a portion of the soils 

 in water, I satisfied myself that there was not contained in 

 them any coarse sand ; so that the whole was formed by a 

 union of particles so minutely divided as to present no 

 consistency in the mass ; but forming a paste with water, 

 and cracking when that liquid was evaporated. The only 

 difference between the argillaceous soils and these is, that 

 the latter when dried do not possess the hardness of the 

 former, but on the contrary fall, under the pressure of the 

 hand, into a nearly impalpable powder. The state of these 

 soils is owing to their having been exhausted by long cul- 

 tivation : some of the kind which I have owned, I have 

 been able to restore to fertility by applying a portion of 

 sandy marl containing ^/^ of calcareous sand. 



Calcareous soils possess properties entirely opposite to 

 those of the argillaceous soils ; the rains filtrate easily 

 through them, and they throw off moisture readily by evap- 

 oration ; the air can penetrate them, to deposit amongst 

 their particles the moisture with which it is charged : and 

 this, especially in hot climates, conduces greatly to their 

 fertility. The tillage of these soils is always easy ; and as 

 they are light and porous, provided they have sufficient 

 depth, roots spread in them easily. Though, from their 

 character, these soils do not require so much amendment 

 as those that are argillaceous, they may still be im- 

 proved ; especially by giving to them the power of retain^ 

 kig water for a longer time, that they may thus be better 

 able to supply the wants of plants : for this purpose, it is 



