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XCVIII. Account of some Improvements in the Construc- 

 tion of a, Stove for Plants, by which Bottom heat is imparted 

 to their Roots, without the use of Tan. By William 

 Kent, Esq. F. L. S. 



Read May 6, 1817. 



Having occasion to rebuild my hot-house, I was led to 

 consider what improvements might be made in the direc- 

 tions of the flue, and the construction of the pit, in order 

 that the fire might not only sufficiently heat the body of 

 the house, but also be so directed as to supersede the 

 necessity of tan : for, independent of the expense, in 

 consequence of the distance whence I had to obtain it, 

 tan is liable to the objection of producing worms, which 

 not only prove highly injurious to the plants, but often 

 totally destroy them. I conceived, that this advantage 

 might be obtained, if an air chamber could be formed 

 under the pit, wherein the air might be confined in a state 

 of high rarefaction, and be so regulated, as to increase and 

 decrease the temperature, as required : for, if an artificial 

 heat could be imparted to the substance which filled the 

 pit, and kept up about the pots, it would be of little conse- 

 quence, of what that substance consisted ; and as tan is 

 only used for this specific purpose, the heated air in the 

 chamber would convey a warmth equivalent to that pro- 

 duced by it. The house being now finished, agreeably to 

 vol. ii. 3 F 



