By Thomas Andrew Knight, Esq. 225 



along the surface of the ground, under the fermenting mate- 

 rial, and communicates with the cavity of the wall, into which 

 it admits the external air to occupy the place of that which 

 has become warm and passed into the pit. The entrances 

 into these passages are furnished with grates, to prevent the 

 ingress of vermin of every kind. The hot-bed is moved and 

 renewed in small successive portions, so that the temperature 

 may be permanently preserved, the ground being made to 

 descend a little towards the wall on every side, that the bed 

 in shrinking may rather fall towards than from the walls ; 

 and I entertain no doubt but that the perpetual ingress of 

 warm air, even without an internal leaf bed, will prove suffi- 

 cient to preserve Pine Apple plants without the protection 

 of mats, except in very severe weather. I have nothing fur- 

 ther to add, but that the Melon plants are the most healthy 

 and luxuriant that I ever possessed, and that their fruit is 

 swelling with more than ordinary rapidity. I annex a sketch 

 of a section and plan of the Pit, without which, I fear, the 

 preceding account would scarcely prove intelligible. 



The perforations in the interior of the wall, are from 

 eighteen to nearly twenty inches distant from each other, 

 and they do not begin till the fifth row of bricks from the 

 bottom. When the Pit is intended for early Cucumbers, or 

 Melons, and the lower part is consequently to be filled with 

 leaves or tan, the holes in the bricks should only be made 

 above the surface of whatever may be put into the Pit, or, if 

 previously made below, must be closed. 



