288 GREEN-HOUSE BULBOUS ROOTS. [December 



reguiar as possible. The thermometer should be kept in the 

 centre of the house, aud 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 majr 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 th.'i 

 house. A green-house compactly and closely built, and the 

 lowest row of top sash all covered with shutters (which no 

 houue ought to be constructed without), will seldom requiiv, 

 artificial heat; but by being long kept close, the damp will 

 increase. In such case give a kittle fire heat, and admit air 

 to purify the house. In fresh mild weather, give liberal por- 

 tions of air all over the house : ai.d though there is a little 

 frost, while mild, and the sun shining, the plants will be bene- 

 fited 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 louger 

 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. Hyacinths 

 grow neatest by being kept very close to the top glass ; the 

 flower-stems are thereby stronger and shorter. Water mode- 

 rately until they begin to grow freely 



