STOVE AND FURNACE HEAT. 687 
and an open fire-place. The amount of air which hourly passes through a close 
stove, heated with a brisk fire, is, on an average, equal to only about one-tenth 
of the capacity of the room warmed, and consequently such stove requires, if 
unaided, ten hours to effect a change of the atmosphere in every such apart- 
ment. Thus stagnant and heated, the air becomes filled with the impurities of 
respiration and cutaneous transpiration. 
Moisture, too, is an important consideration. The atmosphere, whether 
within doors or without, can only contain a certain proportion of moisture to 
each cubic foot, and no more, according to temperature. At eighty degrees it 
is capable of containing five times as much as at thirty-two degrees. Hence, an 
atmosphere at thirty-two degrees with its requisite supply of moisture, introduced 
into a confined space and heated up to eighty degrees, has its capacity for mois- 
ture so increased as to dry and wither everything with which it comes in contact : 
furniture cracks and warps, seams open in the molding, wainscoting, and doors ; 
plants die; ophthalmia, catarrh, and bronchitis are common family complaints, 
and consumption is not infrequent. But this condition of house air is not pe- 
culiar to stove-heat. It is equally true of any overheated and confined atmos- 
phere. The chief difference is, that warming the air by means of a close stove 
is more quickly accomplished and more easily kept up than by any other means. 
Sometimes, by the scorching of dust afloat in the atmosphere, an unpleasant 
odor is evolved which is erroneously supposed to be a special indication of im- 
purity, caused by burning the air. It is an indication of excessive heat of the 
stove. But the air cannot be said to burn, in any true sense of the word, for it 
continues to possess its due proportion of elementary constituents. Such is the 
close stove and its dangers, under the most unfavorable circumstances. The 
Dutch stove is occasionally found in country railroad depots and similar places, 
where the frequent opening of doors makes amends for its deficiencies. In Rus- 
sia, and other northern countries of Europe, stoves are frequently built of brick 
covered with porcelain, with relatively small fire-chambers near the bottom, and 
with winding smoke-flues which traverse many times through the structure, until 
nearly the whole of the heat generated is expended in it. The smoke-pipe, now 
comparatively cool, enters a flue in the wall and carries off the smoke only, while 
the heated mass of brick continues to retain heat and warm the room long after 
all the fuel is burned — for from eight to ten hours. If the same quantity of fuel 
were burned in an open fire grate or close stove, the heat therefrom would be 
expended in an hour. 
Stoves have been so improved in recent years, in the United States espec- 
ially, and are obtainable at such moderate expense, that no excuse for the con- 
tinued use of such as have been above described now exists. Indeed, so import- 
ant and rapid have been the improvements in the construction of stoves in the 
United States within the last eight or ten years, that it is difficult to find a market 
for those of older date. In England, where the people continue to be wedded 
to open grates, and where most is said by scientific persons against the ust of 
stoves, improvements have been exceedingly slow and complicated, and the 
