A. As air is a bad conductor, it will draw off the heat of the tongue very slowly, and, therefore, appear warm; but when there is only a very little air in the egg (as the white is a pretty good conductor), the heat of the tongue will be more rapidly drawn off, and the egg appear colder.
Q. Why is the large end of an egg cracked, when put into a saucepan to boil?
A. To let the air out; if the large end were not cracked, the air (expanded by the heat) would enter the white of the egg, and give it an offensive taste.
PART II.
AIR.
CHAPTER XVIII.
Q. Of what is atmospheric air composed?