The thick downy clothing of some vegetables seems designed to protect them from the injuries of cold, like the wool of animals.  Those bodies, which are bad conductors of electricity, are also bad conductors of heat, as glass, wax, air.  Hence either of the two former of these may be melted by the flame of a blow-pipe very near the fingers which hold it without burning them; and the last, by being confined on the surface of animal bodies, in the interstices of their fur or wool, prevents the escape of their natural warmth; to which should be added, that the hairs themselves are imperfect conductors.  The fat or oil of whales, and other northern animals, seems designed for the same purpose of preventing the too sudden escape of the heat of the body in cold climates.  Snow protects vegetables which are covered by it from cold, both because it is a bad conductor of heat itself, and contains much air in its pores.  If a piece of camphor be immersed in a snow-ball, except one extremity of it, on setting fire to this, as the snow melts, the water becomes absorbed into the surrounding snow by capillary attraction; on this account, when living animals are buried in snow, they are not moistened by it; but the cavity enlarges as the snow dissolves, affording them both a dry and warm habitation.]

         —­So, warm and buoyant in his oily mail,
        Gambols on seas of ice the unwieldy Whale;
        Wide-waving fins round floating islands urge
        His bulk gigantic through the troubled surge;
295 With hideous yawn the flying shoals He seeks,
        Or clasps with fringe of horn his massy cheeks;
        Lifts o’er the tossing wave his nostrils bare,
        And spouts pellucid columns into air;
        The silvery arches catch the setting beams,
300 And transient rainbows tremble o’er the streams.

        Weak with nice sense, the chaste MIMOSA stands,
        From each rude touch withdraws her timid hands;
        Oft as light clouds o’er-pass the Summer-glade,
        Alarm’d she trembles at the moving shade;
305 And feels, alive through all her tender form,
        The whisper’d murmurs of the gathering storm;
        Shuts her sweet eye-lids to approaching night;
        And hails with freshen’d charms the rising light.

[Mimosa.  I. 301.  The sensitive plant.  Of the class Polygamy, one house.  Naturalists have not explained the immediate cause of the collapsing of the sensitive plant; the leaves meet and close in the night during the sleep of the plant, or when exposed to much cold in the day-time, in the same manner as when they are affected by external violence, folding their upper surfaces together, and in part over each other like scales or tiles; so as to expose as little of the upper surface as may be to the air; but do not indeed collapse quite so far, since I have found, when touched in the night during their sleep, they fall still further; especially when touched on