Why is it advisable to use a double boiler for cooking rice? (See Lesson
XX)
If rice is cooked in a double boiler and milk is to be added, why should
not the milk be added until the rice mixture is placed over hot water?
(See statement regarding the scorching of milk in Questions, Lesson
XXIV)
Which method of cooking the Rice Pudding—baking or cooking over water— requires more milk? Explain your answer. Also explain why a definite quantity of milk cannot be stated in the recipe.
See "Note," Lesson XVI. Is any of the injurious substance formed in caramelizing sugar present in Caramel Sauce?
LESSON XXII
CEREALS AND THE FIRELESS COOKER
THE FIRELESS COOKER.—The fact that fuels are expensive and that the supply of some fuels is diminishing, makes it advisable to conserve heat. This can be done in no more satisfactory way than by means of a fireless cooker.
It has been said that future historians in summing up the great achievements of the first quarter of the twentieth century will probably name as the most important, wireless telegraphy, aviation, and fireless cookery. The fireless cooker cannot be used with all methods of cooking, but its possibilities are many.
[Illustration: Courtesy of McCray Refrigerator Co FIGURE 25.
—INSULATED WALL OF A REFRIGERATOR.]
THE PRINCIPLE OF FIRELESS COOKERY.—In Experiment 2 it was found that wood did not transmit heat rapidly, while tin did. Another familiar illustration will show the difference between wood and metal in transmitting heat. A metal door knob feels very cold on a winter day, because the metal conducts the heat away from the hand rapidly, while a wooden knob is comfortable to touch. Wood is termed a poor conductor of heat. Metals are good conductors of heat.