b. Are all substances equally good conductors of
heat? Repeat (a) with a glass rod or a long
splinter of wood, instead of the wire. Does
the other end grow as hot? Hold a test tube
two-thirds full of water in a flame, but at an
angle so that the water at the top is directly
heated. Can you get the water at the top hot
while the water at the bottom is still cool ? Is
water a good conductor of heat ? Is air ?
c. Test the relative conductivity of two saucepans
by taking two of different materials (as for
example, one of aluminum and one of granite).
Pour into them equal amounts of cold water,
and place them over two flames which are
equally hot, or heat first one and then the
other. Determine which boils in the shorter
time.
B. SCRAMBLE AN EGG.
Serve on a slice of toast. Decide how the heat has
been transmitted to each in the cooking.
SCRAMBLED EGG.
Beat an egg slightly, add a tablespoon of milk, and sea-
son with pepper and salt. Pour into a pan in which a
teaspoon of butter✪ Scrambled Eggs on Toast has been melted, and cook, scrap-
ing the mixture from the pan as it sets, until all is
creamy.
116 FOOD STUDY
FIRELESS COOKERS
There is an old story of a man who was held to be a
wizard because he could blow both hot and cold ; he blew
on his hands to warm them and on his soup to cool it. But
fireless cookers can do just as seemingly contrary things,
since they can keep hot things hot and cool things cool.
All that is necessary is that they be constructed in such a
way that little heat can pass in or out of them.
The simplest form of fireless cooker is the hay box ;
literally a box stuffed with hay which, with the air spaces
between, makes a non-conductor of heat. Usually, the
hay is kept from scattering by covering it with stout cloth.
Whatever is to be cooked is placed in water in a saucepan
or pail, heated to boiling, tightly covered, and placed in the
center of the hay. The difficulty with this type of cooker
is that some steam with the odor of the food escapes from
the cooking vessel and is absorbed by the hay, which gradu-
ally becomes musty and must be replaced. More efficient
cookers are lined with non-absorbing material, such as
enameled metal, which can be washed if desired. The
metal, being a fairly good conductor of heat, even when
enameled, must be made double with an air space between.
Further insulation can be put between these two layers.
This type is commonly furnished with soapstones, which
can be heated as hot as desired and placed inside to increase
the heat and make even baking possible.
Of course, none of these cookers is so constructed that
no heat can escape, and, gradually, the material inside be-
comes cold. The efficiency of different cookers is measured
by the heat that is retained after some hours of standing.
To test, equal amounts of boiling water are put in dif-
ferent cookers, and the temperature of water is taken after
a given number of hours.
FIRELESS COOKERS 117
Food study
1917Page 59 · 1 recipe record on this page
Presented as published in 1917. 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
b. Are all substances equally good conductors of heat? Repeat (a) with a glass rod or a long splinter of wood, instead of the wire. Does the other end grow as hot? Hold a test tube two-thirds full of water in a flame, but at an angle so that the water at the top is directly heated. Can you get the water at the top hot while the water at the bottom is still cool ? Is water a good conductor of heat ? Is air ?
c. Test the relative conductivity of two saucepans by taking two of different materials (as for example, one of aluminum and one of granite). Pour into them equal amounts of cold water, and place them over two flames which are equally hot, or heat first one and then the other. Determine which boils in the shorter time.
B. SCRAMBLE AN EGG.
Serve on a slice of toast. Decide how the heat has been transmitted to each in the cooking.
SCRAMBLED EGG.
Beat an egg slightly, add a tablespoon of milk, and season with pepper and salt. Pour into a pan in which a teaspoon of butter has been melted, and cook, scraping the mixture from the pan as it sets, until all is creamy.
FIRELESS COOKERS
There is an old story of a man who was held to be a wizard because he could blow both hot and cold ; he blew on his hands to warm them and on his soup to cool it. But fireless cookers can do just as seemingly contrary things, since they can keep hot things hot and cool things cool. All that is necessary is that they be constructed in such a way that little heat can pass in or out of them.
The simplest form of fireless cooker is the hay box ; literally a box stuffed with hay which, with the air spaces between, makes a non-conductor of heat. Usually, the hay is kept from scattering by covering it with stout cloth. Whatever is to be cooked is placed in water in a saucepan or pail, heated to boiling, tightly covered, and placed in the center of the hay. The difficulty with this type of cooker is that some steam with the odor of the food escapes from the cooking vessel and is absorbed by the hay, which gradually becomes musty and must be replaced. More efficient cookers are lined with non-absorbing material, such as enameled metal, which can be washed if desired. The metal, being a fairly good conductor of heat, even when enameled, must be made double with an air space between. Further insulation can be put between these two layers. This type is commonly furnished with soapstones, which can be heated as hot as desired and placed inside to increase the heat and make even baking possible.
Of course, none of these cookers is so constructed that no heat can escape, and, gradually, the material inside becomes cold. The efficiency of different cookers is measured by the heat that is retained after some hours of standing. To test, equal amounts of boiling water are put in different cookers, and the temperature of water is taken after a given number of hours.
FIRELESS COOKERS 117
Records on this page
Scrambled Eggs on Toast