THE PEACH-HOUSB. 157 



tlon of both, and the last is best ; because, if an arched 

 trench is used without the pipe, there is danger that cracks 

 may occur, and thus let in a stream of smoke and heat 

 upon the trees or fruit ; while, if the pipe only is em- 

 ployed, there is danger of overheating. A pipe, enclosed 

 in a trench, provides against both dangers. The trench 

 and pipe should extend the entire length of the building, 

 and a vertical flue, or chimney, should occupy precisely 

 the same relative position on the outside of the second 

 wall, that the furnace does on the first. 



There is, as a rule, very little inconvenience felt from 

 the difference in the heat at the extreme ends of the flue ; 

 but should it be necessary, it can be equalized, in a great 

 measure, in one or other of the two following simple 

 ways : make the casing of the pipe thinner as it recedes 

 from the furnace, or increase the volume of the pipe. By 

 the former method, the heat will bo sooner radiated, and 

 by the latter, more radiating surface will be provided, as 

 the distance from the furnace increases. The heat thrown 

 out can also be modified by the depth of the trench as 

 well as the thickness of the casing. A mild, uniform heat 

 should be aimed at. 



When only one row of trees is to be planted, the flue 

 should pass about one foot inside the north wall, the aim 

 being to have it as far removed from the trees and fruit 

 as practicable. But if two rows, then six feet from the 

 north wall will be as nearly the proper phice as may be, 

 the hight of the roof at the north, equalizing the greater 

 horizontal distance from the south. Sometimes the flue 

 is in the center of the house, but the objection to this is 

 that the temperature is never equable. A less serious one 

 is that it obstructs the light. 



The whole floor of the peach-house, but especially the 

 borders, in which the trees are to be planted, should be 

 of good, friable, productive soil. Not only so, but also 

 the soil outside both the north and south walls^ where 



