“Very good indeed, Frank,” said Uncle George. “And now I am going to show you something which will prove all this very nicely.”
He then took a saucer and poured some water into it. He placed a piece of lighted candle in the middle of the dish and put a lamp chimney over it. The candle burned for a few seconds and then went out.
“Why does the candle go out?” he asked.
“Because it has used up that part of the air which makes things burn,” said Tom.
“That is right,” said Uncle George, and he began to cut a piece of stout card, shaped like the letter T, but broader every way. The upright part fitted into the top of the lamp chimney.
“We are now going to give the candle flame a stream of fresh air,” he said, as he fitted the piece of card into the chimney.
The candle was again lit and the chimney placed over it. This time it did not go out. It burned brightly, and the flame seemed to be blown from side to side.
“That is very strange,” said Frank.
Draught in Chimney Glass.