10. Drafts. — In still air a candle-flame streams
straight upward, because of the constant upward draft
caused by the heating of air near the flame. As this
air rises, air from below flows toward the candle to take
its place. This in turn becomes hot and rises, thus
starting a draft that continues as long as the candle
burns. And, while the burning of the candle keeps up
the draft, this draft supplies the candle with oxygen to
keep it burning. When we place a lamp-chimney over
the candle, leaving a space at the bottom, we make the
draft stronger by shutting off side-drafts. The flame
flickers, and the candle burns faster. But if either the
opening at the top of the chimney, or the space between
chimney and table be closed, all draft is stopped, and as
soon as the oxygen then inside the chimney is used up,
the candle goes out. To keep up combustion, then, we
must have a draft. For a draft through an enclosed
space two opeyiings are necessary^ one to let air in, the
other to let it out.
11. Products of combustion. — The candle, after burn-
ing for a time, is shorter than when first lighted, because
it has, little by little, united with oxygen to form new
gases which stream off unseen. One of these gases is
carbon dioxide, as is shown by the clouding of the
lime-water on the loop of wire. Besides this, water is
10 THEORY AND PRACTICE OF COOKERY
formed from oxygen and a substance in wax called
hydrogen {water -maker). Substances foriped as a result
of combustion are called products of combustion. Some
of the carbon is not burned at once, but floats in tiny
particles in the flame. If some cold object, such as a
saucer, be held in the flame, this carbon is deposited on
it as soot. Ordinarily, unburned carbon goes off as
smoke. We may state the process of combustion some-
what like an example in arithmetic : candle -f- air = car-
bon dioxide and water.
12. Nothing destroyed in combustion. — By letting H
stand for hydrogen, 0 for oxygen, and G for carbon, and,
taking into account that oxygen unites with just half its
bulk of carbon and with twice its bulk of hydrogen, we
have C + 2 0 = CO,,, and 2 H + 0 = HaO.
The water, smoke, carbon dioxide, and other gases pro-
duced would, if weighed, exactly equal the weight of the
burned candle plus that of the oxygen used in burning it.
Nothing has been destroyed.
13. Burning in oxygen. — In pure oxygen, combustion
is more rapid and energetic than in air, iron and other
substances that will not burn in air burning readily in
oxygen. Could we use iron stoves if our atmosphere
were pure oxygen ? In oxygen or in air, however,
combustion is essentially the same; whether in fire-
place, stove, or lamp; whether a single match burns, or
a whole building. Wherever combustion takes place,
something unites with oxygen, giving off heat (and
usually light), and forming products of combustion.
The story of Prometheus, who is fabled to have stolen fire from
heaven, is told on p. 19 of Buljinch's Mythology. You may also
PREPARATORY LESSONS 11
like to read in Early Chapters in Science about combustion, on
p. 328, and carbon dioxide, on p. 332 ; and in either The Fairyland
of Science, pp. 50-72, or in the Domestic Science Reader, pp. 123-
131, about "The Aerial Ocean in which We Live."
Section 2. The Kitchen Fire — Fuels
A clean fire, a clean hearth. — Charles Lamb.
Page 8
Presented as published in 1901. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
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10. Drafts. — In still air a candle-flame streams
straight upward, because of the constant upward draft
caused by the heating of air near the flame. As this
air rises, air from below flows toward the candle to take
its place. This in turn becomes hot and rises, thus
starting a draft that continues as long as the candle
burns. And, while the burning of the candle keeps up
the draft, this draft supplies the candle with oxygen to
keep it burning. When we place a lamp-chimney over
the candle, leaving a space at the bottom, we make the
draft stronger by shutting off side-drafts. The flame
flickers, and the candle burns faster. But if either the
opening at the top of the chimney, or the space between
chimney and table be closed, all draft is stopped, and as
soon as the oxygen then inside the chimney is used up,
the candle goes out. To keep up combustion, then, we
must have a draft. For a draft through an enclosed
space two opeyiings are necessary^ one to let air in, the
other to let it out.
11. Products of combustion. — The candle, after burn-
ing for a time, is shorter than when first lighted, because
it has, little by little, united with oxygen to form new
gases which stream off unseen. One of these gases is
carbon dioxide, as is shown by the clouding of the
lime-water on the loop of wire. Besides this, water is
10 THEORY AND PRACTICE OF COOKERY
formed from oxygen and a substance in wax called
hydrogen {water -maker). Substances foriped as a result
of combustion are called products of combustion. Some
of the carbon is not burned at once, but floats in tiny
particles in the flame. If some cold object, such as a
saucer, be held in the flame, this carbon is deposited on
it as soot. Ordinarily, unburned carbon goes off as
smoke. We may state the process of combustion some-
what like an example in arithmetic : candle -f- air = car-
bon dioxide and water.
12. Nothing destroyed in combustion. — By letting H
stand for hydrogen, 0 for oxygen, and G for carbon, and,
taking into account that oxygen unites with just half its
bulk of carbon and with twice its bulk of hydrogen, we
have C + 2 0 = CO,,, and 2 H + 0 = HaO.
The water, smoke, carbon dioxide, and other gases pro-
duced would, if weighed, exactly equal the weight of the
burned candle plus that of the oxygen used in burning it.
Nothing has been destroyed.
13. Burning in oxygen. — In pure oxygen, combustion
is more rapid and energetic than in air, iron and other
substances that will not burn in air burning readily in
oxygen. Could we use iron stoves if our atmosphere
were pure oxygen ? In oxygen or in air, however,
combustion is essentially the same; whether in fire-
place, stove, or lamp; whether a single match burns, or
a whole building. Wherever combustion takes place,
something unites with oxygen, giving off heat (and
usually light), and forming products of combustion.
The story of Prometheus, who is fabled to have stolen fire from
heaven, is told on p. 19 of Buljinch's Mythology. You may also
PREPARATORY LESSONS 11
like to read in Early Chapters in Science about combustion, on
p. 328, and carbon dioxide, on p. 332 ; and in either The Fairyland
of Science, pp. 50-72, or in the Domestic Science Reader, pp. 123-
131, about "The Aerial Ocean in which We Live."
Section 2. The Kitchen Fire — Fuels
A clean fire, a clean hearth. — Charles Lamb.