A. White will not radiate heat: if, therefore, the inside of a boiler be white, the liquor in it is kept hot much longer.
Q. Why is the bottom of a kettle nearly cold, when the water is boiling hot?
A. Black soot is a very bad conductor of heat; and, therefore, the heat of the boiling water is some considerable time, before it gets through the soot which adheres to the bottom of the kettle.
Q. Why is the lid of a kettle so intensely hot, when the water boils?
A. The bright metal lid of the kettle is an admirable conductor of heat; and, therefore, the heat from the boiling water pours into our hand the moment we touch it.
Q. Show the benefit of smoke in cooking.
A. The carbon of the fuel (which flies off in smoke) naturally blackens all culinary vessels set upon the fire to boil, and thus renders them fit for use.
(“Culinary vessels” are vessels used in kitchens for cooking, as saucepans, boilers, kettles, &c.)
Q. How does smoke make culinary vessels fit for use?
A. If it were not for the smoke, (which gathers round a kettle or saucepan) heat would not be absorbed, and the process of boiling would be greatly retarded.