here is something else in the air that
mixes with the oxygen and weakens it."

"Makes a sort of gaseous grog of it, eh?" said Mr. Bagges. "But how is
that proved?"

"Why, there is a gas, called nitrous gas, which, if you mix it with
oxygen, takes all the oxygen into itself, and the mixture of the nitrous
gas and oxygen, if you put water with it, goes into the water. Mix
nitrous gas and air together in a jar over water, and the nitrous gas
takes away the oxygen, and then the water sucks up the mixed oxygen and
nitrous gas, and that part of the air which weakens the oxygen is left
behind. Burning phosphorus in confined air will also take all the oxygen
from it, and there are other ways of doing the same thing. The portion
of air left behind is called nitrogen. You wouldn't know it from common
air by the look; it has no color, taste, nor smell, and it won't burn.
But things won't burn in it either; and any thing on fire put into it
goes out directly. It isn't fit to breathe; and a mouse, or any animal,
shut up in it dies. It isn't poisonous, though; creatures only die in it
for want of oxygen. We breathe it with oxygen, and then it does no harm,
but good; for if we breathe pure oxygen, we should breathe away so
violently, that we should soon breathe our life out. In the same way, if
the air were nothing but oxygen, a candle would not last above a minute."

"What a tallow-chandler's bill we should have!" remarked Mrs. Wilkinson.

"'If a house were on fire in oxygen,' as Professor Faraday said, 'every
iron bar, or rafter, or pillar, every nail and iron tool, and the
fire-place itself; all the zinc and copper roofs, and leaden coverings,
and gutters, and; pipes, would consume and burn, increasing the
combustion.'"

"That would be, indeed, burning 'like a house on fire,'" observed Mr.
Bagges.

"'Think,'" said Harry, continuing his quotation, "'of the Houses of
Parliament, or a steam-engine manufactory. Think of an iron-proof
chest--no proof against oxygen. Think of a locomotive and its
train--every engine, every carriage, and even every rail would be set on
fire and burnt up.' So now, uncle, I think you see what the use of
nitrogen is, and especially how it prevents a candle from burning out
too fast."

"Eh?" said Mr. Bagges. "Well, I will say I do think we are under
considerable obligations to nitrogen."

"I have explained to you, uncle," pursued Harry, "how a candle, in
burning, turns into water. But it turns into