114 The Principles of Fruit -growing. 



fire,, is quickly condensed as it comes in contact 

 with the surrounding air. The heat of condensation 

 thus becomes manifest in the lower air. The heat 

 of the fire is thus in a measure trapped and dis- 

 tributed throughout the lower stratum of the air, 

 and greatly aids in protecting the plants. Every 

 quart of water thus evaporated and again con- 

 densed in the surrounding air would be sufficient 

 to raise the temperature ten degrees throughout a 

 space eighty feet square and deep." 



Smudges have long been used in the vineyards 

 of parts of Europe. A sketch of some of the 

 practices may add to the interest of this discussion.* 

 "Protection from frost is often secured by the use 

 of smudges, namely, piles or bundles of such stuff 

 as will produce a great smoke while burning. They 

 are placed around the field and lighted at the ap- 

 proach of frost, and the smoke which arises from 

 trees hanging over the fields, will, after the man- 

 ner of clouds, tend to keep the escaping heat near 

 the earth. Pliny is said to have recommended the 

 practice, and as early as the sixteenth century it 

 was advised by the great French agriculturist, Olivier 

 de Serres, who wrote: 'Frost is repelled from the 

 vine if, foreseeing it, you produce in various parts 

 of your vineyard thick smokes by means of wet 

 straw or half -rotten manures. These sunder the air 

 and dissolve the nuisance. * * * * Prepare 

 them in good season by building here and there in 

 your fields little piles of the above mentioned matters, 



* Prepared by my student, W. S. Andrews, B. A. 





