C. 12.] EXPLANATION OF THE PLATES 



and more fpungy than thofe of the other 

 parts. 



Some who give defigns for hot-walls, ad- 

 vife building the breaft of the firft flue a 

 brick on bed, and that of the other a brick 

 on edge, without decreafing the depth of the 

 flues, as they afcend, in order to give an 

 equality of heat to the furface. But this 

 matter is better accompliihed by the gra^ 

 dual diminution of the flues, as here fhewn, 

 though the breaft of all the flues are a 

 brick on bed. A wall of this kind is more 

 fubje6t to the viciflitudes of the weather 

 than a flue in a hot-houfe ; and, confe- 

 quently> the breaft of the flue being a brick 

 on bed, will keep a more conftant heat, 

 when once warmed, than when on edge. 

 To prevent accidents, however, a trellis 

 ihould be fixed, or fpars an inch thick, nail- 

 ed againft they/r/? courfe of the flue, where- 

 on to drefs the trees ; above which they 

 rnay be drefled to the \vall without the 

 leaft apprehenfion of danger. (See Chap. 

 VIII. 5ed. XL) 



Fig. 2. reprefents the plan and fectionof 



a mufhroom-houfe, worked by one fire, and 



4ivjided for the purpofe of producing- them 



P 3 in 



