“Was there any other way of doing the same thing?” Nichols inquired, as he rose lankily and stood over Loris.
“Yes!” declared Drew. “I can look back over what I found in the technical books about electricity and telephony and see several other ways for Cuthbert to accomplish the same result. The electrical pistol did not necessarily have to be actuated by the human voice.”
“How terrible!” Loris whispered, with her brow puckering. “Perhaps others will use the same idea to slay their enemies.”
“We’ll keep it a close secret,” the detective said. “It rests with us four, now. Outside of us, there is only Morphy who knows.”
“How else could the pistol be discharged?”
“Two other ways that I see, Miss Stockbridge. It would be rather easy to arrange a little magnetic trigger in the receiver. This trigger could be actuated by an excess of current—say the connecting of a hundred and ten volt lighting circuit on the line. It might burn out the magnet wiring, but it would also release the trigger and fire the cartridge.”
“That’s like a door-catch?”
“Yes,” said Drew. “Like a door-catch operated by a magnet or like the firing pin of a large cannon. They’re not all operated by lanyards. Some work with push-buttons.”
Nichols passed his hand over his brow. “I know another way,” he said, glancing down at Loris. “There is a way which is far cleverer than Cuthbert thought of. It could be done by a tuning-fork or reed.”
“Certainly!” exclaimed Drew. “I never thought of that. A reed attuned to a certain voice could be adapted to trip a trigger. Then the loaded receiver could be set so that one of your friends who had a peculiar voice, either high or low, would slay you. Rather terrifying revenge, that!”