We bent over the little machine, straining our eyes and ears to catch the visual and audible signals which it gave.
Gradually the light faded, as the thermopile adjusted itself to the change in temperature.
Suddenly, without warning, a low-toned bell rang before us and a bright-green light flashed up.
"That can have only one meaning," cried Craig excitedly. "Some one is down there in that inferno—perhaps the bomb-maker himself."
The bell continued to ring and the light to glow, showing that whoever was there had actually started the electric furnace. What was he preparing to do? I felt that, even though we knew there was some one there, it did us little good. I, for one, had no relish for the job of bearding such a lion in his den.
We looked at Kennedy, wondering what he would do next. From the package in which he had brought the two registering machines he quietly took another package, wrapped up, about eighteen inches long and apparently very heavy. As he did so he kept his attention fixed on the telethermometer. Was he going to wait until the bomb-maker had finished what he had come to accomplish?
It was perhaps fifteen minutes after our first alarm that the signals began to weaken.
"Does that mean that he has gone—escaped?" inquired Carton anxiously.
"No. It means that his furnace is going at full power and that he has forgotten it. It is what I am waiting for. Come on."
Seizing the package as he hurried from the room,
