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LXIIL AN ACCOUNT OF SOME IMPROVEMENTS IN THE CONSTRUCTION 



OF HOTBEDS. 



[Read before the HORTICULTURAL SOCIETY, July 3rd, 1827.] 



I SUBMIT an account of a small addition which I have made in the 

 machinery of a common hotbed, from the use of which I believe that 

 every gardener who has occasion to raise cucumbers and other plants in 

 winter, or very early in the spring, will be able to derive very considerable 

 advantages. At these periods of the year, it is not easy to give the plants 

 a sufficiently high temperature, with proper change of air, however well 

 the bed may have been constructed, and with whatever care the material 

 which composes it may have been prepared ; and the sudden changes of 

 temperature which often occur in the climate of England will frequently 

 subject the roots of the plants to be injured by excess of heat, and the 

 mould, when lying upon horse -dung, to be what is called by the gardener 

 barned, that is, I believe, so much impregnated with ammonia, that the 

 roots of the plants cannot retain life in it. Another defect of the common 

 hotbed is, that whilst its interior part is excessively hot, so little heat 

 ascends through the mould, that a covering of glass alone does not afford suf- 

 ficient protection to any tender plant in very cold weather, during the night. 



By means of the machinery which I shall proceed to describe and to 

 recommend, abundant air may be given at all times, and so high a 

 temperature preserved, that, with a hotbed of a very moderate degree 

 of strength, the most tender plant will be perfectly protected without any 

 other covering than that of an ordinary glass-light during the severest 

 frost of our climate, provided the spaces where the panes of glass overlap 

 each other be perfectly closed. 



The annexed design will give a sufficiently accurate representation of 



