“Wonder what that is?” asked Terry.
“Don’t ask me,” shrugged Rhodes. “I thought there was no one in that place.”
Don turned to Jim. “Doesn’t that look to you like the Morse code?” he asked.
Jim nodded. “I think it is. Let’s see if we can catch anything.”
The four boys in the boat sat silently and watched the flashes from the house across the water. They knew that the signals were being made with a mirror, into which the descending sun was pouring its last rays. Flash followed flash, some of them long and some of them short. To Rhodes and Terry they meant nothing, but to the Mercer brothers, who had once been very familiar with the telegraph code, it was plain that two words were being repeated. When the flashes had ceased they looked at each other, startled.
“What did you make out of it?” asked Don.
“Why—why, it seemed to me, if I was reading correctly,” stammered Jim, “that whoever it was was signalling the words ‘No progress.’ Is that what you got?”
“Yes,” his brother nodded. “That is just what I got. ‘No progress’ is right.”
“But what in the world can ‘no progress’ mean?” asked Terry.
“I don’t know,” answered Don. “But it means that something is going on in that old hall.”