Ill 



cock near to the boiler, so that the tank or hot water 

 flue may be heated without affecting the air in the 

 house. The other two pipes from the boiler to be 

 connected with the tank or flue, underneath the tan 

 bed ; they may be of smaller size, and a wooden plug 

 must be formed, partially to exclude the hot water 

 when the heat is too violent ; and whether a tank or 

 flue is to supply the bottom-heat, they must be 

 chambered over ; and if circulated in a flue, it may be 

 eight or nine inches wide, and four inches high, and 

 must pass all round the bed one-and-a-half feet from 

 the wall, and may be lined with either lead or zinc, or 

 plastered with Roman cement ; it may be covered 

 with flags. But previous to building the flue, the 

 bottom of the bed ought to be filled two feet with 

 compost for the vine roots ; and flags or bricks laid 

 all round, on which the flue must be built. A flue 

 thus constructed will give plenty of bottom heat for 

 the pines, and will keep the soil and other materials 

 moist, under which the vine roots may be expected to 

 grow rapidly ; and in very cold weather the cavity in 

 the wall may be opened, which communicates with 

 the heated chamber, in order to maintain a sufficient 

 heat for the atmosphere ; and upon the chamber in 

 the pit, must be placed 20 inches of the materials to 

 plunge in the plants. The roof sloping to the north 

 and south, as well as the upright ends, will have 

 to be glazed, and all the laps filled with putty, 



