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XLJX. Account of a Method of Constructing Flues for 

 Hot-houses. In a Letter to the Secretary. By James 

 Robert Gowen, Esq. F. H. S. 



Read December 15, 1818. 



Dear Sir, 



In the second volume of the Transactions of the Horticul- 

 tural Society * Mr. Knight remarks, " if a brick flue be 

 made of much too great thickness, I have ascertained by 

 experiment, that it will continue to absorb the heat of a mode- 

 rate fire during months, without ever being hot itself, or ma- 

 terially raising the temperature of the house, though the air 

 enter at a very high, and go out at a low temperature, 

 and more heat disappear than would be sufficient to burn 

 the plants, if the heated air were made to pass through a 

 tube of cast iron." 



The justice of the President's observation is incontroverti- 

 ble, and as an opposite principle has generally influenced the 

 construction of hot-house flues, I request you will do me the 

 honour of laying before the Society some account of a flue 

 which was built under my direction, in the Earl of Carnar- 

 von's Pine stoves, at Highclere, in the summer of 1817, before 

 I read Mr. Knight's paper, upon which it forms an excellent 

 practical commentary ; you saw the flue yourself last summer, 

 but unluckily at a season when it was not in use. It entirely 

 surrounds the house, and is completely insulated, being kept 



* See Vol. ii. page 325. 



