243 
such a degree, that no favourable weather will afterwards 
restore their vigour ; and it is upon those soils which have 
the least power of retaining heat, (and which power is nearly- 
proportionate to the absolute weight of given bulks,) that this 
effect is most visible. Those which are most puffy, pulveru- 
lent, or " deaf," or that are light in weight in propor- 
tion to a determinate volume, are the most affected with 
" clover sickness." Upon some of the stilfer soils of the new 
red sandstone formation, when drained, if the clover seed 
vegetates or is not killed by wet at the time of sowing, the 
crop seldom disappears in the winter and spring. Red clover 
is also frequently destroyed in the early period of its growth 
by the slug. If there be a luxuriant growth of straw, the 
clover is frequently drawn up and becomes weakened, so that 
it is unable to endure the rigour of a severe autumn and 
winter, even on soils best adapted to its growth ; and it cer- 
tainly succeeds the most favourably where the corn crop is 
light. 
In confirmation of the opinion that clover is destroyed by 
cold, and does not disappear by reason of "clover sickness," 
or the land being " tired," the following additional proof is 
given. Mr. Turner, of Barton, near Exeter, states from the 
result of more than twenty years' experience, that in nineteen 
cases out of twenty, its failure is entirely owing to the stubble 
being fed bare after harvest, and the plant being so weakened 
thereby, as to prevent its standing the wet and cold of the 
succeeding winter ; and that in every instance in which it has 
not been fed off in the autumn, that piece has been the admira- 
tion of every one the following spring.* Upon the whole, it 
may be questioned whether the crop of seeds, averaging in 
many places only about a ton per acre, and that principally 
composed of rye grass, which certainly has an exhausting 
effect on the wheat crop, would be better supplied by a crop 
* Journal of Royal Agricultural Society, Vol. I, Part 4. 
