34 



Fig. 2. Section of house, showing bottom heat 

 chamber, cold air drains, and direction of the cur- 

 rents ; a, entrance for cold air ; b, cold air drains ; e, 

 bottom heat chamber. 



l£4.Feet. 



Fig. 3. Longitudinal section of house, showing hot 

 air chamber, furnace built of Stourbridge brick, and 

 surrounded with two inches of sand, and covered over 

 with a half-inch iron plate in three widths ; the cis- 

 tern is made of iron, four inches deep, in two divi- 

 sions, and fed through a pipe from above ; the roof 

 has a cavity to be filled with sawdust, to prevent the 

 escape of heat ; c, entrance for hot air ; d, furnace. 



Ventilation. — The accumulation of gaseous mat- 



