THIRTY USEFUL DEVICES 



109 



supplies heat and ventilation or a supply of fresh, warm 

 air. Any kind of a flat top stove or even a kerosene 

 stove will give sufficient heat. The size of the stove 

 should depend on the size of the house, but forty 

 degrees is a sufficient heat. The illustration shows a 

 closed box a yard square and an inch deep, made of 

 ordinary sheet iron. The box or heater is placed on 

 a small stove, or if legs are attached to each corner of 



FIG IO6: LAMP HEATER 



the heater, a lamp may be placed under it. The cold 

 air comes in at a, passes through the box, becoming 

 heated, and emerges at the pipe b. The cold air pipe 

 is one-half inch in diameter and the warm air pipe one 

 inch. The pipe a should be long enough to extend 

 through the walls to the outside, so as to bring in the 

 pure air. No ventilators on the top of the building 

 will be required, and the air will keep the house dry. 

 Always bring the air in and discharge it near the roof, 



