to be heated by Dung. 21 



bining some part of each, in the most simple and economical 

 form possible. This I have accomplished by supporting my 

 frame, of two lights, on six posts, each about three feet high, 

 placed in two rows at the back and front {fig. 13.) ; these posts 

 are braced together at the 15 



top by pieces of fir, about 

 two inches thick and three 

 inches wide ; these are halved 

 together at the corners, that 

 the frame may have an equal 

 bearing. The two ends have 

 three pieces of inch-deal, .^JLgggp 

 nailed across them from back 

 to front, as has also the centre, by which the space under the 

 frame is divided into two compartments. The upper part, on 

 which the frame rests, has rails nailed across from side to 

 side, leaving openings of three or four inches between each, 

 except in the front, where a space is left about nine inches 

 wide. This is covered by a board having six round holes 

 sawed in at equal distances, each six inches in diameter, which 

 holes are covered by as many common flower-pots, reversed 

 and luted down (see^. 13.), so as to prevent the steam from 

 passing into the bed, except when wanted ; for which purpose 

 the holes at the top of the pots are fitted with plugs which can be 

 removed at pleasure. These reversed pots appear to answer all 

 the purposes of the flue in M'Phail's pit, and I find them very 

 useful in assisting to throw a fine heat into the bed. I have 

 added these pots on the suggestion of Mr. W. Mitchinson, who 

 is, I believe, a contributor to your Magazine, and is a very 

 clever and scientific gardener. Over the other openings, laths 

 or other pieces of straight wood are nailed, but not entirely 

 close. On this flooring I put first a layer of straw an inch or 

 two thick, and then about the same depth of very rotten stable 

 dung ; but I have not allowed either the straw or rotten dung 

 to overlay the board on which the reversed pots are fixed. I 

 then placed the frame on the stage, and filled the two com- 

 partments with hot stable-dung, and added a light lining round 

 the outside nearly to the top of the frame. This lining is 

 covered by four broad boards to keep off the rain, and to draw 

 up the heat ; under each light I placed as usual about a cubic 

 foot of compost, and in forty-eight hours the heat came up 

 sufficiently to warm the earth in the bed ; but, as the steam 

 came partially through the stratum of rotten dung, I pressed 

 it very firmly down, and particularly so round the sides, which 

 entirely excluded it, and the following day I put in my plants, 



c 3 



