how queer it smells!" exclaimed Hal.

"Sulphur!" ejaculated Grandpa Martin.

He and the children looked at the queer blue fire that seemed to come
from inside the rock. What could it mean?

CHAPTER XX

THE HAPPY TRAMP

Grandpa Martin stood looking down at the queer, burning rock. The blue
fire was flaming up brighter now, and it made a strange light on the
faces of the Curlytops and Hal as they gathered about. The sky was
cloudy and it was getting dark.

"Oh, what is it? What is it?" asked Ted and Jan.

"It smells just like old-fashioned sulphur matches that my grandmother
used to light," said Nora, who had come out, having seen the queer light
from the cook-tent.

"And it _is_ sulphur that is burning," said Grandpa Martin. "That rock
has sulphur in it, not gold, Hal. And it is the sulphur that is burning
with the blue fire."

"But what makes it?" asked the children.

Grandpa Martin did not answer for a few seconds. He stood again looking
down at the flaming blue rock. Mrs. Martin, who had started to put
Trouble to bed early, came out and looked.

"It's like something I once saw in the theater," said the maid. "I don't
like it--that blue light. It reminds me of the time our house was struck
by lightning--that sulphur smell."

"It is the same smell," said Mr. Martin. "Curlytops, I think you have
found something very queer in this blue rock. I don't know just what it
is, but we'll find out. See, the stone is burning like a lump of coal
now, but with a blue flame instead of red."

"Just like the night we saw the blue fire on the island before we came
camping here," said Ted. "Is it the same thing, Grandpa?"

"I don't know. Perhaps it is. Where did you get the blue rocks?"

"Over in the woods," answered Hal. "There's a great big one there. As
big as this tent."

"Is there?" some one suddenly asked. "Then please show me where it is!
Oh, can it be that at last I have found what I have been looking for so
long?"

The Curlytops and the others turned at the sound of this new and strange
voice. A man seemed to spring out of the bushes back of the tent. By
the light of the blue fire Ted and Jan saw that his clothes were ragged
and torn in many places.

"Oh! Oh!" gasped Jan. "That's the tramp!"

"Well, I guess maybe I do look like a tramp, all ragged and dirty as I
am," laughed the man, and his voice sounded pleasant. "But I am not a
regular tramp. I am Mr. Weston--Alfred Weston," he went on, speak