Q. Why is boiling water kept hot best in a bright metal pot?
A. Because bright metal being a bad radiator will not throw off the heat of the boiling water from its surface.
Q. Why is water kept cold in summer-time in a bright metal pot, better than in an earthen vessel?
A. Because bright metal will not absorb heat from the hot air, like an earthen vessel; in consequence of which, the water is kept cooler.
Q. Why are dinner-covers made of bright tin or silver?
A. Light-coloured and highly-polished metal is a very bad radiator of heat; and, therefore, bright tin or silver will not allow the heat of the cooked food to escape through the cover by radiation.
Q. Why should a meat-cover be very brightly polished?
A. If the cover be dull or scratched it will absorb heat from the hot food beneath it; and (instead of keeping it hot) will make it cold.
Q. Why should a silver meat-cover be plain, and not chased?
A. If the cover be chased, it will absorb the heat of the food covered by it; and instead of keeping it hot, will make it cold by absorption.