286 GREEN-HOUSE — BULBOUS ROOTS. [Deceniber. 
regular as possible. The thermometer should be kept in the 
centre of the house, and free from the effects of reflection. 
As noticed last month, sun heat may be as high as 50° in 
the house, and would not be hurtful, but it should not con- 
tinue so for any considerable time without admission of air. 
The fire heat should not exceed 45°, and never below 35°. 
It ought not to continue at that point — 36° is the lowest for 
a continuation that with safety can be practised ; and where a 
collection of Cactii are kept, 40° should be the lowest. So 
that no error may occur, the temperature ought to be known 
in the coolest and warmest parts of the house, and the varia- 
tion remembered ; then whatever part of the house the ther- 
mometer is placed, a true calculation of the heat of the whole 
interior can be made. We would recommend to the inexperi- 
enced to keep the thermometer in the coldest part of the 
house. A green-house compactly and closely built, and the 
lowest row of top sash all covered with shutters (which no 
house ought to be constructed without), will seldom require 
artificial heat; but by being long kept close, the damp will 
increase. In such case give a little fire heat, and admit air 
to purify the house. In fresh mild weather, give liberal por- 
tions of air all over the house : and though there is a little 
frost, while mild, and the sun shining, the plants will be 
benefited by a small portion of air for the space of an hour, 
or even for half of that time. 
Whatever state the weather may be through the winter, 
never keep the house long shut up. Thirty-six hours should 
be the longest time at once ; rather give a little fire heat. 
We are no advocates for keeping plants in the dark, and 
never think that our plants are receiving justice if kept longer 
in darkness than one night. 
BULBOUS ROOTS. 
Those that were plunged in the garden, if not lifted and 
brought under cover, this should now be done without delay. 
Clean the pots, and stir up the surface of the soil. Hya- 
cinths grow neatest by being kept very close to the top glass; 
the flower-stems are thereby stronger and shorter. Water 
moderately until they begin to grow freely. 
