20 Cultivation of the Potatoe. 
But if the potatoes are raised in damp weather, it is better to 
spread them out on a floor, and let them dry there. 
A. point of great importance is to cover heaps over with a 
layer of straw, at least six inches thick. This layer of straw 
should be thickest near the ground; it should there extend 
beyond the heap of potatoes, so as completely to prevent the 
access of frost. The straw should be well filled at the sum- 
mit and angles, and the whole covered up with earth. It is 
not, indeed, the earth which protects the potatoes from frost ; 
this effect is produced by the straw, which prevents the radia- 
tion of heat from them; but the earth should be closely pressed 
to prevent the air getting through the straw. Earth which 
has no consistencc and easily crumbles is, therefore, unfit for 
the purpose; if no other can be obtained, some kind of cov- 
ering must be placed over it. 
A precaution very necessary to be observed, is not to close 
the heaps completely in autumn so long as the weather con- 
tinues warm. A small quantity of air must be allowed access 
through the top till the frost comes on; a vent will thus be 
afforded for vapors which rise from the heap. Covering 
the heaps with dung is always useless and often mischievous. 
When a thaw comes on it is prudent to open the heaps a 
little at the top, to permit the escape of vapor. 
