edge with you--I need help--help to learn
the secret and help to make the diamonds--see, there are some of the
first ones made, but I have been defrauded of my rights--I need the
aid of a young fellow like you. Will you help? See, I'll give you
some diamonds now. They are genuine, though they are not like
ordinary diamonds. I made them. Will you--"

Before Tom could answer, there came a warning rumble of the earth,
and a great fissure opened, almost at the feet of Mr. Jenks, who,
with a cry of fear, leaped toward the young inventor.

CHAPTER XIX

SECRET OPERATIONS

"Help me save this machinery!" yelled Tom, whose first thought was
for the electrical apparatus. "Don't let it fall into that chasm!"

For the crack had widened, until it was almost to the place where
the parts of the wrecked airship had been carried.

"The machinery? What do I care about the machinery?" cried Mr.
Jenks. "I want to save my life!"

"And this machinery is our only hope!" retorted Tom. He began
tugging at the heavy dynamos and gasolene engine, but he might have
saved himself the trouble, for with the same suddenness with which
it opened, the crack closed again. The shock had done it, and, as if
satisfied with that phenomena, the earthquake ceased, and the island
no longer trembled.

"That was a light one," spoke Tom, with an air of relief. He was
becoming used to the shocks now, and, when he saw that his precious
machinery was not damaged he could view the earth tremors calmly.

"Slight!" exclaimed Mr. Jenks. "Well, I don't call it so. But I see
Captain Mentor and Mr. Hosbrook coming. Please don't say anything to
them about the diamonds. I'll see you again," and with that, the
queer Mr. Jenks walked away.

"We came to see if you were hurt," called the captain, as he neared
the young inventor.

"No, I'm all right. How about the others?"

"Only frightened," replied the yacht owner. "This is getting awful.
I hoped we were free from the shocks, but they still continue."

"And I guess they will," added Tom. "We certainly are on Earthquake
Island!"

"Mr. Parker, the scientist, says this last shock bears out his
theory," went on the millionaire. "He says it will be only a
question of a few days when the whole island will disappear."

"Comforting, to say the least," commented Tom.

"I should say so. But what are you doing, Mr. Swift?"

"Trying an experiment," answered the young inventor, in some
confusion. He was not yet r