It was not long after the almost miraculous escape of Elaine and myself from the blowing up of the bridge on the shore road that Del Mar returned from his mysterious mission which had, apparently, taken him actually down to the bottom of the sea.
The panel in the wall of his library opened and in the still dripping submarine suit, holding under his arm the weird helmet, Del Mar entered. No sooner had he begun to remove his wet diving-suit than the man who had signalled with the heliograph that we had found Del Mar's message from "below," whatever that might mean, entered the house and was announced by the valet.
"Let him come in immediately," ordered Del Mar, placing his suit in a closet. Then to the man, as he entered, he said, "Well, what's new?"
"Quite a bit," returned the man, frowning still over Elaine's accidental discovery of the under-water communication. "The Dodge girl happened to pick up one of the tubes with a message just after you went down. I tried to get her by blowing up the bridge, but it didn't work, somehow."
"We'll have to silence her," remarked Del Mar angrily with a sinister frown. "You stay here and wait for orders."
A moment later he made his way down to a private dock on his grounds and jumped aboard a trim little speed boat moored there. He started the motor and off the boat feathered in a cloud of spray.
It was only a moment by water before he reached the Dodge dock. There he tied his boat and hurried up the dock.
. . . . . . .
Elaine and I arrived home without any further experiences after our hairbreadth escape from the explosion at the bridge.
We were in doubt at first, however, just what to do about the mysterious message which we had picked up in the harbor.