DESCRIPTION OF HOTHOUSES. 129 



and long in proportion, say forty feet or more, 

 two or more fire-places will be necessary, each 

 having its separate range of flues, divided into 

 equal proportions, with a chimney attached to 

 each division. Where there are two pits ranged 

 along the house, one before the other, then the 

 flue may be carried along the space between 

 them ; but in this case the flue must be detached 

 from the bark pit bed, not less than two or 

 three inches, to prevent the heat drying the 

 bark too much, or it might be in danger of 

 taking fire by accident, through overheating the 

 flues : but for houses of moderate width, with 

 only one pit, the flues ranged round the house 

 as described above, will be sufficient. 



It will be necessary occasionally to cleanse the 

 flues when they become clogged with soot, for 

 which purpose, places should be contrived in the 

 brickwork, at convenient distances, to make a 

 small opening, or by the removal of tiles ; but 

 be careful that those apertures are made per- 

 fectly secure again. 



At the furnace, or commencement of the first 

 flue, it is requisite to have a regulator or register, 



G 5 



