Combustion

"L ET us light a shovelful of charcoal in the kitchen stove. The charcoal catches fire, turns red, and is consumed, while at the same time producing heat. Before many minutes there is nothing left but a handful of ashes weighing but a trifle compared with the quantity of charcoal burned. What, then, has become of the charcoal?"

"It has been consumed," answered Jules; "it is burnt up."

"Agreed. But being consumed—does that mean being reduced to nothing? Does charcoal, when once it has been burned, become nothing at all, absolutely nothing?"

"It has turned to ashes," Jules replied.

"You haven't hit it yet, for the ashes left after combustion amount to very little compared with the quantity of charcoal consumed."

"Your question, dear Uncle," Marie here interposed, "puzzles not only Jules, but me too, very much indeed. If there isn't any more than a handful of ashes left after the charcoal is burnt up, I should say the rest has been destroyed."

"If that is your opinion I would have you know that in this world nothing is ever entirely destroyed, not a particle of matter ever becomes nothing after having been something. Try to annihilate a grain of sand. You can crush it, convert it into impalpable powder; but reduce it to nothing—never. Nor could the most skilful of men, men equipped with more varied and more powerful appliances than ours, succeed any better. In defiance of every exertion of ingenuity or violence the grain of sand will still continue to exist in some form or other. Annihilation and accident, two big words that we use at every turn, really do not mean anything. Everything obeys laws: everything persists, is indestructible. The shape, aspect, appearance, changes; the underlying substance remains the same.

"So the charcoal that is burned is not annihilated. True, it is no longer in the stove; but it is in the air, dissipated and invisible. When you put a lump of sugar into water the sugar melts, is disseminated throughout the liquid, and from that time ceases to be visible even to the keenest scrutiny. But that sugar has not ceased to exist. The proof is that it communicates to the water a new property, a sweet taste. Furthermore, nothing stands in the way of its ultimate reappearance in its original form. All we have to do is to expose the sweetened water to the sun in a saucer; the water will disappear in vapor and the sugar remain.

"Charcoal behaves in like manner. In burning it is dissipated in the air and becomes invisible. This dissipation is called combustion. What do we do when we wish to make the fire burn faster? With the bellows we blow air on the fuel. With each puff the fire revives and burns brighter. The live coals, at first dull red, become bright red and then white-hot. Air breathes new life into the bosom of the burning mass. If we wish, on the other hand, to prevent a too rapid consumption of fuel, what do we do? We cover the fire with ashes, thus keeping out the air. Under this layer of ashes the live coals retain their heat and remain red for a long time without being consumed. Thus it is that a fire in a grate is maintained only by the constant admission of air, which makes the coal burn; and the faster it burns, the greater the amount of heat given off."

"Then that must be why the stove gets so hot when it roars," remarked Claire. "Air is let in between the bars of the grate and then goes roaring through the red-hot coals. But if the air is prevented from circulating by closing the door of the ash-pit, the heat subsides at once."

"When the air is impregnated with carbon it acquires new properties, just as water does on becoming charged with salt or sugar. This new element is an injurious substance, a harmful gas, all the more to be feared because it does not reveal its presence, having neither smell nor color. We do not take note of it any more than we do of ordinary air.

"But let any one breathe this formidable gas, and immediately the brain becomes clouded, torpor supervenes, strength fails, and unless help arrives death soon follows. You have all heard of unfortunate persons who inadvertently—sometimes, alas! designedly—have met death in a closed room by lighting a brazier. The fact that the air becomes impregnated with the dissipated carbon from the burning charcoal explains these lamentable accidents. Inhaled even in a small quantity, this deadly gas induces first a violent headache and a general sense of discomfort, then loss of feeling, vertigo, nausea, and extreme weakness. If this state continues even a very little while, life itself is endangered.

"You see to what a risk charcoal exposes us when the products of its combustion do not escape outside through a chimney, but spread freely indoors, especially if the room is small and tightly closed. Under these conditions you cannot be too distrustful of a brazier. Whether burning brightly or half extinguished, whether covered with ashes or not, these embers exhale a deadly gas which does not announce its presence by any sign that we can recognize, but, like a traitor, always takes us by surprise. Death may occur even before danger is suspected.

"Again, it is very imprudent to close the damper of a bedroom stove for the sake of maintaining a moderate heat during the night. The stovepipe being closed by the damper, there is no longer any outlet for the products of combustion, which are sent out into the room and asphyxiate the sleepers, so that they pass from life to death without even waking up.

"If the apartment is small and without openings for changing the air, a simple foot-warmer is enough to cause a headache and even lead to more serious results."

"Now I understand," said Marie, "the headaches I sometimes have in winter when I am sewing in my little room, all shut up with a foot-warmer under my feet. It was the burning charcoal that gave me those headaches. That is a good thing to know, and I will be careful in the future."

"Be just as careful with charcoal when you are ironing. Keep the heater for the irons under the chimney or in a well-ventilated place, so that the dangerous exhalations from the embers may be carried out into the open air. Those who do ironing often complain of an uncomfortable feeling which they attribute to the smell of the iron, whereas it is due to the deleterious gas given off by the burning charcoal. It can be avoided by keeping the heaters under a chimney or in a current of air that drives away the injurious gas."