CHAPTER V
AN EXCITING HUNT
"What is that rocking?" cried Harry, jumping out of his couch, one night.
The Professor was awake and had noticed it.
"Probably an earthquake."
The rocking continued for several minutes, and then gradually subsided. They boys were so excited that sleep was out of the question, for the time, besides the shaking might again recur at any moment.
"Do you think there is any danger, Professor?"
"It is impossible to say what will happen when these symptoms in the earth's crust take place."
"Are there not some instruments which indicate the extent and possible dangers of the quakes?"