Farmers' bulletin (United States. Dept. of Agriculture); no. 1096

"All frost protection methods, from the simplest to the most complicated, can be carried on more successfully if the processes by which the earth's surface cools at night and the factors which influence the rate of cooling are well understood. In the first part of this bulletin an attempt has been made to describe in a simple, elementary manner the changes that take place at and near the earth's surface on a frosty night, so that persons protecting plants or trees may be able to understand how their protective devices operate to prevent damage and in what manner they are most efficient. In treating a matter of this kind it is practically impossible to eliminate all technical terms, but so far as possible these have been carefully explained in simple language. The larger portion is given over to a discussion of the various methods and devices now being used for protection against frost, together with a chapter on temperatures injurious to plants, blossoms, and fruit." -- p.