"From red and blue caps screwed over the electric searchlight," was the reply. "All of our electrics are provided with these signal caps."
"There, the light is red again!" cried Ed.
"I'll show how how it works," Will said, bringing out his own flashlight and unscrewing the false cover from the loading end.
Directly he had the blue and red caps out, and then the red one was fastened over the eye of the searchlight.
"There, you see!" Will exclaimed turning on the light. "We've got a beautiful red light and that means a Morse dash."
"I see," answered Ed. "And when you turn on the blue, that means a dot. I learned the Morse code, of course, when I was admitted to the Boy Scouts, but I never knew that it was used in that way."
"I wonder if he sees this?" asked Will as he swung the red light back and forth in the growing twilight.
"We'll have to wait and see," replied Ed. "Of course, he'll answer if he knows we're here!"
Swiftly the light changed from red to blue and from blue back to red again. This took place several times and then Will said:
"Now, count!"