104 



GENEEAL SCIENCE 



Heating of Air by Convection. Heating by hot-air furnaces is 

 already more or less popular. There are some things which it is very 



. 82. The arrows show the circulation of air as produced in the room by the 

 radiator. Why does the air over the radiator rise? If the hot air is rising 

 why do you feel heat if you stand beside the radiator? Why does the air 

 on the opposite side of the room fall and return toward the radiator? 



FIG. .83. By what process is this house heated? 



important that we should know about this form of heating. The 

 manner in* which the air enters the room should be considered first. 



