"Recent pamphlets lay the blame of all the bad effects of anthracite furnaces and stoves to the carbonic oxide mingled in the air. I think these pamphlets have a bad influence. _Excessive dryness_ also has bad effects. So also the excessive heat in the evenings and coolness in the mornings has a share in these evils. But how much in addition is owing to carbonic oxide, we can not know, until we know something of the actual amount of this gas in rooms, and as yet we know absolutely nothing definite. In fact, it will be a difficult thing to _prove_." There are other difficulties connected with furnaces which should be considered. It is necessary to perfect health that an equal circulation of the blood be preserved. The greatest impediment to this is keeping the head warmer than the feet. This is especially to be avoided in a nation where the brain is by constant activity drawing the blood from the extremities. And nowhere is this more important than in schools, churches, colleges, lecture and recitation-rooms, where the brain is called into active exercise. And yet, furnace-heated rooms always keep the feet in the coldest air, on cool floors, while the head is in the warmest air. Another difficulty is the fact that all bodies tend to radiate their heat to each other, till an equal temperature exists. Thus, the human body is constantly radiating its heat to the walls, floors, and cooler bodies around. At the same time, a thermometer is affected in the same way, radiating its heat to cooler bodies around, so that it always marks a lower degree of heat than actually exists in the warm air around it. Owing to these facts, the injected air of a furnace is always warmer than is good for the lungs, and much warmer than is ever needed in rooms warmed by radiation from fires or heated surfaces. The cooler the air we inspire, the more oxygen is received, the faster the blood circulates, and the greater is the vigor imparted to brain, nerves, and muscles. Scientific men have been contriving various modes of meeting these difficulties, and at the close of this volume some results will be given to aid a woman in selecting and managing the most healthful and economical furnace, or in providing some better method of warming a house. Some account will also be given of the danger involved in gas-stoves, and some other recent inventions for cooking and heating. VI. HOME DECORATION.