Pulverisation and soil temperatore

1210. The temperature of a soil is increased by pulverisation. Earths, Grisenthwaite observes, are among the worst conductors of heat with which we are acquainted, and consequently it would be a considerable time before the gradually increasing temperature of spring could communicate its genial warmth to the roots of vegetables, if the lower parts of soils were not heated by some other means. It is therefore necessary to have the surface of the soil open, that there may be a free ingress of the warm air, and tepid rain of spring.