weather, would make no draught at all to speak of. If you build
high, you must build thick, so that the interior of the chimney
will hold its warmth all the way up."
"How did people ever manage without chimneys?"
said Lawrence; "for I read the other day that they were unknown in
ancient times, and that they were considered a luxury, which only the
rich could indulge in, even in the age of Queen Elizabeth."
"They made a fire in the middle of a room,
wigwam fashion, and let the smoke get out through a hole in the roof
the best way it could," said the Doctor.
"Glass-makers must have labored under an
inconvenience," said the gaffer. "I have a little book called
'Reminiscences of Glass-Making,' which has drawings in it of the
old-fashioned Italian and French glass furnaces. They have no high
chimneys; but the smoke is shown coming out of short flues into the
room where the blowers are at work. Their draught must have been
very uncertain. A fire must have air."
"It is established," remarked the Doctor,
"that for every pound of bituminous coal near two hundred cubic
feet of common air are required to make an economical fire,-- that
is, to mix with and burn all the gases; and that, in a fire like this,
the weight of the air consumed is greater than that of all the other
materials that go into the furnace,-- coal, ore, everything."
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