Q. Is iron a good absorber of heat?
A. No; iron is a good conductor, but a very bad absorber of heat.
Q. Why do the fender and fire-irons (which lie upon it) remain cold, although they are before a good fire?
A. Because the metal fender and fire-irons have very little capacity for absorbing heat; although they are soon made hot (by conduction), when placed in contact with the hot fire or stove.
Q. Why does a kettle boil faster, when the bottom and back are covered with soot?
A. The black soot absorbs heat very quickly from the fire, and the metal conducts it to the water.
Q. Why will not a new kettle boil so fast as an old one?
A. Because the bottom and sides of a new kettle are clean and bright; but in an old kettle are covered with soot.
Q. Why would the kettle be slower boiling, if the bottom and back were clean and bright?