Convection. — AYhen the minute particles, or molecules,
of which bodies are composed, in their vibration, come in
contact with hot bodies, they will themselves become warm.
It is in this way that gases and liquids are heated. Air in a
room, or in a tightly closed space like an oven, is heated by
coming in contact with heated surfaces, the currents in the
air keeping the temperature more nearly equal. In heating
water it is the circulation, depending upon the difference in
temperature of various parts, which, by bringing every par-
THE KITCHEN 53
tide in contact with the heated surface of the dish, causes
the water to become hot. This method of ]ieat transmission
is called convection, or heating by contact. Most cooking is
done by heat transmitted by convection.
In any cooking apparatus, then, loss of heat occurs when
the material presents a rough, luipolished surface, has many
projecting portions (ornamentations ?), or is placed where
currents of air may strike it. For economy of heat all cook-
ing apparatus must be highly polished or enamelled, free
from all but essential projections, and so placed while in
use that no drafts may cross or strike it. In ovens, non-
conducting material, as asbestos, may be used between sheets
of iron or steel, further to prevent loss of heat. This is
done in the Aladdin oven and in some steel ranges.
Care of Range. — Every morning clean the ashes from the
top of the oven, leaving a very thin layer to act as a non-
conducting medium and so prevent excessive top heat in the
oven. Close all drafts and shake the ashes out of the grate
into the ash pan. If there is an ash sifter above the ash pan
sift the ashes to save unburned coal, otherwise the ashes
must be sifted later when they are removed. Carefully
remove all ashes, as if left they absorb heat and are waste-
ful. Return ash pan to its place, save unburned coal for
use on fire when well burning. Brush any remaining ashes
into ash box and remove clinkers.
Laying Fire. — Crush paper and place in empty fire-box,
lightly place on this finely split wood laid like lattice work,
on this arrange a second layer of slightly larger kindling
which should be of hard wood. Replace covers and light
the paper from underneath. See that all dampers are open
and checks closed. When the wood begins to burn, in about
three minutes, add two shovelfuls coal so placed as to rest
on the burning wood. When this ignites add coal to fill the
box to within one or two inches of the covers — never above
54 HANDBOOK OF DOMESTIC SCIENCE
top of oven, otherwise there will not be air space to cause a
draft. In few minutes, five usually, depending on strength
of draft, close the smoke damper so as to send the heated
air around the oven and up the chimney. Keep the lower
draft open till the coal begins to look red in a few places,
then close all drafts. This fire should need no further
attention for several hours. When the coals are all red, but
not beginning to look white, add a fresh shovelful of coal
so that the oven may not be cooled, but be kept at a steady,
even heat. In an ordinary school kitchen range in constant
use for five hours, two hods of coal should last three days.
Page 30
Presented as published in 1900. 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
Convection. — AYhen the minute particles, or molecules, of which bodies are composed, in their vibration, come in contact with hot bodies, they will themselves become warm. It is in this way that gases and liquids are heated. Air in a room, or in a tightly closed space like an oven, is heated by coming in contact with heated surfaces, the currents in the air keeping the temperature more nearly equal. In heating water it is the circulation, depending upon the difference in temperature of various parts, which, by bringing every par-
tide in contact with the heated surface of the dish, causes the water to become hot. This method of heat transmission is called convection, or heating by contact. Most cooking is done by heat transmitted by convection.
In any cooking apparatus, then, loss of heat occurs when the material presents a rough, unpolished surface, has many projecting portions (ornamentations ?), or is placed where currents of air may strike it. For economy of heat all cooking apparatus must be highly polished or enamelled, free from all but essential projections, and so placed while in use that no drafts may cross or strike it. In ovens, nonconducting material, as asbestos, may be used between sheets of iron or steel, further to prevent loss of heat. This is done in the Aladdin oven and in some steel ranges.
Care of Range. — Every morning clean the ashes from the top of the oven, leaving a very thin layer to act as a nonconducting medium and so prevent excessive top heat in the oven. Close all drafts and shake the ashes out of the grate into the ash pan. If there is an ash sifter above the ash pan sift the ashes to save unburned coal, otherwise the ashes must be sifted later when they are removed. Carefully remove all ashes, as if left they absorb heat and are wasteful. Return ash pan to its place, save unburned coal for use on fire when well burning. Brush any remaining ashes into ash box and remove clinkers.
Laying Fire. — Crush paper and place in empty fire-box, lightly place on this finely split wood laid like lattice work, on this arrange a second layer of slightly larger kindling which should be of hard wood. Replace covers and light the paper from underneath. See that all dampers are open and checks closed. When the wood begins to burn, in about three minutes, add two shovelfuls coal so placed as to rest on the burning wood. When this ignites add coal to fill the box to within one or two inches of the covers — never above
top of oven, otherwise there will not be air space to cause a draft. In few minutes, five usually, depending on strength of draft, close the smoke damper so as to send the heated air around the oven and up the chimney. Keep the lower draft open till the coal begins to look red in a few places, then close all drafts. This fire should need no further attention for several hours. When the coals are all red, but not beginning to look white, add a fresh shovelful of coal so that the oven may not be cooled, but be kept at a steady, even heat. In an ordinary school kitchen range in constant use for five hours, two hods of coal should last three days.