34:6 Rural Architecture. 



the winter is prevented from doing so by the heat which 

 enters it through the bottom. The same cellar during the 

 summer grows gradually warmer as the season advances 

 and is only relatively cool because part of the heat entering 

 above is conveyed through the bottom into the earth, to re- 

 store that which kept the cellar from freezing during the 

 winter. The warm stable which does not freeze is kept so 

 by the heat of the animals sheltered, and the warmly con- 

 structed stable only makes less animal heat needed to main- 

 tain the temperature ; the walls in themselves are not warm. 

 So, too, no garment however made is in itself warm. We 

 call it warm when the loss of heat through it is slow. 



424. Means of Controlling Temperature. When it is de- 

 sired to construct a room which will be warm in winter 01 

 one which will be cool in summer the same principles must 

 be employed in each. In the first case it is desired to re- 

 tain the heat produced in the room; in the second case to 

 prevent heat coming through the same walls, but from the 

 opposite direction. 



To secure either of these ends two essentials of construc- 

 tion must be observed. The walls must be as nearly air 

 tight and as poor conductors of heat as possible. In tin 

 construction of a warm house, a warm stable, a cool ice 

 house or a cool curing room for cheese the greatest attention 

 should be paid to securing air tight walls because, no mat- 

 ter how poor conductors are put into the walls, if there are 

 cracks about doors and windows or open joints in the wall, 

 the effect of wind pressure and wind suction will be to 

 change the air in the room so rapidly that it will be diffi- 

 cult to keep it either warm or cold. 



425. Solid Masonry Walls. Stone basements with solid 

 walls are sufficiently warm for stables but they are too good 

 conductors of heat to be suitable for dwelling houses in cold 

 climates where the inside temperature must be maintained 

 at 72 F. Hollow brick walls, when plastered with a close 

 textured mortar, through which air cannot pass readily, are 



