HOW TO WARM OUR HOUSES. 237 



that travels nearly 200,000 miles in a second. By convection, or hot 

 air from iron surfaces, we have a comparatively dead or dormant heat 

 that moves only a few feet in the same time. ' By radiation from open 

 fires the air is the coolest thing in the room ; by the air-heating method 

 it is the hottest. By open fires the lungs get less heat than any 

 other part of us, and so are braced and sti-engthened ; by the hot-air 

 process they get more heat than any other part, because the hottest air 

 rises uppermost about the head, and so is inhaled, making the lungs 

 tender and sensitive to cold on our going out. Put a thermometer at 

 the floor, and another at the ceiling, in a room heated by the hot-air 

 process, and you will find the air at the ceiling from 15° to 45° warmer 

 than at the floor. And so the head is surrounded by a torrid atmos- 

 phere, while the feet may be cold. 



We want to warm our bodies, not the air. Cool air is denser, con- 

 tains more oxygen, and warms the blood more than hot air, besides 

 refreshing and strengthening the lungs, and bracing them against in- 

 jury on going out. We want air with a normal amount of ozone. 

 We get it with the ozone all destroyed by the hot-iron surfaces. The 

 Professor of Chemistry in the London University (Dr. Graham, a very 

 high authority) says ozone is destroyed at 140°. 



Suppose the top of your house removed, and the sun shining freely 

 down into it in winter. Your floor, walls, furniture, and your cloth- 

 ing, will have a temperature of, say, 100°, while the air itself will be 

 only at 50° or 60°. An open fire is a miniature sun, and its radiation is 

 governed by the same laws as that of its great prototype. With an open 

 fire put in proper position in your room, while your walls and floor will 

 be at about 80° or 90°, the air will be at 50°. Replace this open fire by 

 an air-heating arrangement, and your floor and walls will be found to 

 be only 50°, more or less, while the air rises from your close stove or 

 your hot-air register at from 140° to 250°. If you doubt it, put a ther- 

 mometer in your register, and see. 



What do we want of such air as this ? Evidently nothing, and so 

 kind Nature sends it upward as quickly as possible, to get it beyond 

 our reach ; but we defeat her beneficent intent by closing the ventila- 

 tors at the ceiling ; and so after cooling somewhat it descends, still 

 far too warm (and robbed of all its ozone, and the refreshing qualities 

 of natural air), to enfeeble the lungs, and render them susceptible of 

 injury on going into the external air. 



The only remedy for all these mischievous conditions and effects is 

 entirely to abandon the plan of applying the heat to the air — of mak- 

 ing the air the carrier of heat. Heat wants no carrier, any more than 

 light. It can outfly Mercury " and the swift-winged couriers of the 

 air." Put your fire in proper position ; take away the iron and brick 

 casings that inclose it and obstruct its natural movements, and, quicker 

 than you can think, the heat will be flashed all over your room ; dart- 

 ing out in straight lines in every direction from the surface of the 



