158 Miscellanies. 
It follows, that this interesting subject remains yet in obscurity, 
perhaps in all respects; and its farther prosecution is more imperi- 
ously called for, by the absolute wants of the community, than that 
of any other to which natural science can be directed. 
Cambridge, E. S. of Maryland, Feb. 26, 1832. 
2. On belts of gel as skreens, for the garden, the orchard, 
vineyard, &c.*—The temperature, in winter, of every living vegeta- 
le,—that is, of some part of it, in which principally resides its vi- 
tality, during the season of its least activity,—is always higher than 
that of a dead vegetable, of the same kind, as is the case also with 
hybernating animals, in their season of torpidity. The natural tem- 
peratures as _— things vary, according to their kinds and_ habi- 
s, of the class of evergreens, in perpetual verdure, con- 
evergreen, and upon the leafless branches of the oak or other deciduous 
tree, produces widely different effects. As if there were a repulsion 
between cold and heat, the ascending blaze of a fire cannot be made 
to come into contact with the bottom of a.tea-kettle or boiler, filled 
with cold water ; but will do so when heated up to near boiling, com- 
ing nearer and nearer as the temperature of the water is raised. 
My supposition is, that the effect of the sun beams is always 
in proportion to the temperature of the thing on which they fall. 
If, for example, the sun beams, in winter, fall on a living and @ 
open air is at zero and that of a hot bed at 60°, for example, its gla- 
zed covering open to the sun—that the rays of the same sun wou 
increase the temperature of the hot bed more than that of the open 
air; or, that when the temperature of the open air is at zero, and 
that of a dwelling room, open to the south by a window, is at 60°, 
indicated by accurate thermometers, both in the shade; that on let- 
ting the rays of the sun fall on each, the rise will be greatest in that 
* This paper was written as part of a series ene the Country Farmer, and 
— = been No. XXIII of a series now in the course of publication in anoth- 
Tr journal 
