DEVELOPMENT OF HOUSE HEATING 



125 



in the warmest portion of 

 the room. The reason for 

 this rule is easily seen. 

 Just as the tallest chimney 

 produces the best draft 

 because it contains the 

 longest column of heated 

 air, so the upward cur- 

 rent of air through the 

 furnace, through the riser 

 which leads from it and 

 into the room above will 

 be strongest if the air is 

 well heated throughout its 

 entire course. By placing 

 the riser in inside walls and the 



FIG. 



FIG. 93. First floor plau for setting 

 furnace. 



92. Basement plan for setting a 

 furnace. 



register in the warmest por- 

 tion of the room, which is 

 usually also near an inside 

 wall, a column of heated, 

 and consequently light air, 

 of the greatest possible 

 length is assured. Were 

 the register placed at the 

 coldest point in the room, 

 the upper portion of the 

 column would be cold air, 

 and consequently heavy 

 air, and the movement of 

 the air through the furnace 

 and riser would be slow 

 and sluggish. A strong 

 and reliable circulation of 

 air is the keynote to success 

 in furnace heating. 



In Fig. 91 the circula- 

 tion of air from a furnace 



