62 
THE FLORIST S JOURNAL. 
is the impact and circulation of fresh air which so rapidly destroys 
the crystalization; and therefore an air-tight building is far more 
efficient than one made deep in the earth. Turf walls and a thick 
conical roof of thatch make the best ice-houses. 
It is probable that the subterranean heat might be available for 
some domestic purposes. For instance, if the lower ends of the 
discharging pipes from the gutters of a roof were let into deep 
cesspools in the ground, a current of warm air would be ever 
ascending up the pipe, and prevent the same from being frozen 
over at the top. And so a small greenhouse, if connected with 
a deep pit by a flue passing from the one to the other, might repel 
any extra degree of frost dangerous to the plants ; and perhaps 
some other advantages may be gained in gardening, by obtaining 
accumulations of this latent heat. But, as already said, deep 
trenching of beds and borders, and breaking through an imper¬ 
vious sub-soil, is the easiest practical expedient for affording to 
plants the excitement of terrestrial radiation. 
Observer. 
ON THE DESTRUCTION OF INSECTS. 
BY JAMES MAIN, F.L.S. 
Floriculture, like every other branch of gardening, has its 
drawbacks, not only from accidents of wind or other weather, but 
from invisible enemies, which harbour in the soil, crawl on its 
surface, or fly in the air. Boots, whether fibrous, tuberous, or 
bulbous, are prej^ed on by insects, or the larvae of insects, which 
live in the ground. The stems and leaves are disfigured by 
slugs and snails; and even the flowers, just ready to burst into 
beauty and fragrance, are utterly destroyed by night-feeding 
insects. 
Every tulip grower has suffered more or less from the ravages of 
the wire-worm, the larva of a kind of beetle belonging to the 
genus Elater of entomologists: the perfect insect is frequently 
seen during summer, in gardens and fields, on the ground, or 
resting on the leaves of plants. It is of a dirty grey colour, 
rather better than half an inch in length, and rather narrow in 
