<:,7 



front be thrown out and shaken back again, with a 

 little addition of new horse dung, and it will continue 

 as long again ; only, let the pits be always kept full 

 up to the boards, and let only one side be shifted at 

 a time, allowing fourteen days between shifting each 

 side of the pits. The inside of the pit is filled up to 

 within three feet of the glass, with tanner's bark, 

 well dried ; for drying is a material thing to be at- 

 tended to in the winter season. Care must be taken 

 not to let any of the bark fall into the flue, or vacant 

 space that is left for the heat to come up. (Caled. 

 Hort. Mem. hi. 336.) 



Fire heat direct. — Mr. Stewart, gardener to Sir It. 

 Preston, at Valleyfield, near Culross, Perthshire, 

 erected a pit in which he built two flues (a } a,) and 



supported over them, on brick props (c), a flooring of 

 pavement, covered with layers of gravel and sand (d), 

 on which he placed the pots ; at the sides were open- 

 ings (6, b,) to admit the heated air from below to 



H 



