moisture to the grass ; but likewise the water car- 
ries nourishment dissolved in it, and defends the 
roots from the effects of cold.” 
No general principles can be laid down respect- 
ing the comparative merit of the different systems 
of cultivation, and the various systems of crops 
adopted in different districts, unless the chemical 
nature of the soil, and the physical circumstances 
to which it is exposed, are fully known. Stiff co- 
herent soils are those most benefited by minute 
division and aeration, and in the drill system of 
husbandry, these effects are produced to the great- 
est extent ; but still the labour and expense con- 
nected with its application in certain districts, may 
not be compensated for by the advantages pro- 
duced, and there are some stiff soils which must be 
left in clods when sown with wheat. Moist cli- 
mates are best fitted for raising the artificial gras- 
ses, oats, and broad-leaved crops ; stiff aluminous 
soils, in general, are most adapted for wheat crops, 
and calcareous soils produce excellent sain-foin 
and clover. 
Nothing is more wanting in agriculture, than 
experiments in which all the circumstances are 
minutely and scientifically detailed. This art will 
advance with rapidity in proportion as it becomes 
exact in its methods. As in physical researches, 
all the causes should be considered ; a difference 
in the results may be produced, eve.n by the fall of 
a half an inch of rain more or less in the course 
of a season, or a few degrees of temperature, or 
even by a slight difference in the sub-soil, or in 
the inclination of the land. 
c 4 
