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56 Bark Beds. As tan is slow of decomposition, and during that 
process, gives out a considerable degree of heat, it becomes an 
important article to the horticulturist, inasmuch as it can be 
procured in many places, at very little cost. Some of our 
friends make hotbeds of it, on a small scale, merely for raising 
their annuals and striking cuttings. It should be remembered 
that a small bed cools quickly, and therefore is less efficient 
than a large one. Also, that as atmospheric air is a slow con- 
ductor of heat, it is advantageous to surround the bed with 
spongy or porous materials. A well-made straw hurdle is more 
efficient in confining heat than a four-inch brick wall. Mr. 
Tyso, in the Gardener’s Magazine, gives the result of several 
years' experience on bark beds. He says, “ My bed is made in 
a brick j)it, nine feet long, five feet six inches broad, and six 
feet deep; and contains more than two waggon loads of tanner’s 
bark. At first, I made the bed in March, of bark exposed two 
or three days to drying winds. This heated sufficiently for a 
time; but when I removed it, in Sej)tember, I found a large por- 
tion of the tan quite dry and perished, by a whitish mould, re- 
taining no heat whatever. In the centre, and towards the bot- 
tom, there was moisture, and about seventy-five degrees of heat. 
I then renewed the bed by two-thirds of fresh tan, just as it came 
from the pits, without drying, and mixed it with another of the 
freshest old tan. In a few days this began to heat, and retained 
a good heat for six months. On this bed I preserved, during 
the winter, a number of pelargoniums and other greenhouse 
plants, giving them all the heat I could by day, and covering up 
at night; and the plants, in general, looked better than those in 
my greenhouse. In the March following I renewed my bed 
again. On this I struck my georginas, raised two crops of me- 
lons, struck my pelargoniums and other plants, and, in Septem- 
ber last, I renewed it again for winter use. My plan has been, 
to sift at least one-third of the old tan, and mix the undecayed 
parts with the new’ tan, until the pit was three parts full, and 
then add fresh tan to complete it.” 
57 Alpine Plants, their Habitat. Few plants present more 
attractions to the cultivator, than those called Alpines. The 
term, as applied to plants cultivated in gardens, comprehends 
not only such as are found wild in mountainous districts, but 
also in low swamps, and peat soil. On mountains, they are 
