Q. Why is a wine-glass (brought out of a cellar into the air) covered with a thick mist in summer-time?
A. The vapour of the hot air is condensed by the cold glass, and covers it as a thick mist.
Q. Why does breathing on a glass make it quite dull?
A. Because the hot breath is condensed by the cold glass; and, therefore, covers it with a thick mist.
Q. Why do walls stand thick with wet in a sudden thaw?
A. The walls (being thick) cannot change their temperature so fast as the thin air can; and, therefore, they retain their cold after the thaw has set in.
Q. How does retaining their cold account for their being so wet?
A. As the vapour of the warm air touches the cold wall, it is chilled and condensed into water, which sticks to the wall, and sometimes trickles down in little streams.
Q. Why does a thick well-built house contract more damp of this kind, than an ordinary one?