can show you the contrary," said Harry. "I take this piece of white
paper, look, and hold it a second or two down upon the candle-flame,
keeping the flame very steady. Now I'll rub off the black of the
smoke, and--there--you find that the paper is scorched in the shape
of a ring; but inside the ring it is only dirtied, and not singed at
all."

"Seeing is believing," remarked the uncle.

"But," proceeded Harry, "there is more in the candle-flame than the
gas that comes out of the candle. You know a candle won't burn without
air. There must be always air around the gas, and touching it like, to
make it burn. If a candle hasn't got enough air, it goes out, or burns
badly, so that some of the vapor inside of the flame comes out through
it in the form of smoke, and this is the reason of a candle smoking.
So now you know why a great clumsy dip smokes more than a neat wax
candle; it is because the thick wick of the dip makes too much fuel in
proportion to the air that can get to it."

"Dear me! Well, I suppose there is a reason for everything," exclaimed
the young philosopher's mamma.

"What should you say now," continued Harry, "if I told you that the
smoke that comes out of a candle is the very thing that makes a candle
light? Yes; a candle shines by consuming its own smoke. The smoke of
a candle is a cloud of small dust, and the little grains of the dust
are bits of charcoal, or carbon, as chemists call it. They are made in
the flame, and burnt in the flame, and, while burning, make the flame
bright. They are burnt the moment they are made; but the flame goes on
making more of them as fast as it burns them: and that is how it keeps
bright. The place they are made in, is in the ease of flame itself,
where the strong heat is. The great heat separates them from the gas
which conies from the melted wax, and, as soon as they touch the air
on the outside of the thin case of flame, they burn."

"Can you tell how it is that the little bits of carbon came the
brightness of the flame?" asked Mr. Wilkinson.

"Because they are pieces of solid matter," answered Harry. "To make
a flame shine, there must always be some solid--or at least
liquid-matter in it."

"Very good." said Mr. Bagges,--"solid stuff necessary to brightness."

"Some gases and other things," resumed Harry, "that burn with a
flame you can hardly see, burn splendidly when something solid is
put into them. Oxygen and hydrogen--tell me if I use too hard words,
un