THE LADIES MAGAZINE OF GARDENING. 
311 
natural safeguard against its severity, the abstraction of heat from our 
bodies being then much less rapid. Such a hard winter,” he adds, 
“ is considered here a blessing next to a good crop ; for the fisherman 
then gets out to sea, the landsman gets in his timber out of the depths of 
the forest, and the inhabitants of the most pathless districts obtain their 
supplies of grain, potatoes, &c., at little cost of transport.” {Tour in 
Sweden, p. 364.) 
The powerful and rapid operation of wind in lowering temperature was 
shown in an experiment of Dr. Heberden, recorded in the Philosophical 
Transactions for 1826. He suspended a thermometer, previously raised to 
100° Fahr., in an atmosphere at 31°, when a strong breeze prevailed, and 
in about half a minute the mercury fell not less than 48°; whilst in an 
atmosphere at 30°, but without any perceptible wind, the fall of the 
mercury previously raised as before to 100°, was only 19° in the same 
period of time. These facts, which doubtless apply to vegetable as well 
as to other bodies, due regard being had to differences in their conducting 
powers, show that degrees of cold may be borne with impunity in an 
atmosphere that is perfectly still; which if accompanied with a brisk 
wind, would be quite intolerable. That such stillness prevails in the 
plant-cases there can be little reason to doubt; for though considerable 
motion may often occur in the air within them, from variations in the 
external heat, yet, as little or none of this air escapes, its temperature, at 
any given period, must be deemed pretty uniform, and cannot be rapidly 
reduced as it is by the frequent contacts and changes of surface which go 
on in the free motions of an agitated atmosphere. In an atmosphere, too, 
which is so still, and in which changes of temperature proceed so slowdy, 
tropical plants may, perhaps, bear, without injury, degrees of cold which 
would prove fatal if occasioned by the frigorific operation of free air in 
constant and rapid motion. 
7- Condition of plants, with regard to light, in close cases and in the free 
atmosphere .—Of the great importance of light to vegetation Mr. Ward is 
fully sensible. “ The success of his plan,” he says, “ will be in proportion 
to the admission of light to all parts, of the growing plants. In every 
place,” he adds, “ where there is light, even in the centre of the most 
crowded and smoky cities, plants of almost every family may be grown by 
this method.” Seeds, it is well known, germinate best when buried in the 
soil, and entirely secluded from light ; but when the young germ pushes 
into day, if light be still excluded, by inverting over it an opaque vessel 
the plant shoots up into a long and feeble stem, is of a pale or whitish 
yellow colour, and possesses little odour or savour. On the contrary, if 
the vessel be transparent, so as to transmit light, the growth is more 
