a host of other details, including the speed at which the boring implements were working. Nay, more; by means of a special telephone he could hear what was going on in these lower regions; and by an ingenious modification of the telautograph, continuous photographs taken at the bottom of the tube were transmitted to his office, so that he could actually see for himself what was taking place at the bottom of the tube. In other words, he could follow every detail of the work as well as if he himself had descended into the bowels of the earth.
It is needless to state that Dr. Giles studied these records with the greatest attention and anxiety; and as the well increased in depth, the furrow in the doctor's brow deepened also, and he took up his post where, night and day, he could keep sharp watch on the fluctuations of the instruments.
He felt that he was now reaching a critical period in his experiment, and he proceeded to take certain precautions which to his assistants seemed uncalled for, but which he knew were absolutely necessary. Among other things, he issued an order that no workman should remain in the caisson unless his presence there was absolutely indispensable. At the same time he had
