BOTTOM HEAT. 9 



air-drains I have described as necessary when pipes are 

 laid, and to connect these subsoil air-chambers with the 

 atmosphere of the interior of the vinery by a series of 

 drain-pipes along the front of the house near the hot- 

 water pipes. Along the back wall of the vinery con- 

 struct an underground air-drain, to be connected by a 

 series of pipes, 4 inches in diameter, with the general 

 underground air-chambers of the border. From this 

 drain another series of pipes should be carried up the 

 back wall some 7 or 8 feet, where they should have 

 openings into the interior of the vinery; and if the flue 

 from the boiler is made to run along the back wall in 

 such a way as to heat the air in the upright air-drains, 

 it will become lighter, and escape into the general at- 

 mosphere of the house; while at the same time a 

 current of air will pass down the front air-pipes 

 already referred to, at a lower temperature than that 

 escaping from the outlets in the back wall, but suffici- 

 ently warm to be of great benefit to the roots of the 

 vines. This arrangement has the additional advantage 

 of keeping the air in the house in constant motion. 

 There is also the possibility of making such arrange- 

 ments in forming a vine -border as to admit of the 

 application of dung-linings for warming the soil. It 

 is, however, only necessary to have heat applied to the 

 roots, as here described, in cases where grapes have to 

 be forced early. If the vines are not started till the 

 beginning of March they will do perfectly well without 

 it, as is evident from everyday experience. 



