"The Lord alone knows," replied Dr. Bird. "I hope that I never have to face one and find out. Well, now that we know what we are fighting, we ought to be able to settle its hash."
"High explosive?" suggested the lieutenant.
"I don't think so. With such a low nervous organization, we would have to tear it practically to pieces to kill it, and I am anxious to keep it from mutilation for scientific study. I have an idea, but I'll have to study a while before I am sure of the details. Send me the radio operator."
The next day the Bureau mechanics began to dismount the apparatus from the tank and to assemble another elaborate contrivance. Before they had made an end of the work additional equipment arrived from Washington, which was incorporated in the new setup. At length Dr. Bird pronounced himself ready for the attempt.
UNDER his direction, three cattle were driven into the cave and there tethered. They were there the next morning unharmed, but the second night the now familiar bellowing and howling came from the depths of the cave and in the morning two of the cattle were gone.
"That will keep him quiet for a day or two," said the doctor, "and now to work!"
The tank made its way into the cave, dragging after it two huge cables which led to an engine-driven generator outside the cave. These cables were attached to the terminals of a large motor which was set up in the cave near the place where the cattle were customarily tethered. This motor was the actuating force which turned two generators, one large and one small. The smaller one was mounted on a platform on wheels, which also contained the spark gaps, the reflectors and other apparatus which produced the beam of ultra-violet light which had been used to photograph the monster.
From the larger generator led two copper bars. One of these was connected to a huge copper plate which was laid flat on the floor of the cave. The other led to a platform which was erected on huge porcelain insulators some fifteen feet above the floor. Huge condensers were set up on this platform, and Dr. Bird announced himself in readiness.
A steer was dragged into the cave and up a temporary runway which led to the platform containing the condensers, and there tied with the copper bus bar from the larger generator fastened to three flexible copper straps which led around the animal's body. When this had been completed, everyone except the doctor, Carnes, and Lieutenant Leffingwell left the cave. These three crouched behind the search-light which sent a mild beam of ultra-violet onto the platform where the steer was held. The engine outside the cave was started, and the three men waited with tense nerves.
For several hours nothing happened. The steer tried from time to time to move and, finding it impossible, set up plaintive bellows for liberty.
"I wish something would happen," muttered the lieutenant. "This is getting on my nerves.
"Something is about to happen," replied Dr. Bird grimly. "Listen to that steer."
THE bellowing of the steer had suddenly increased in volume and, added to the note of discontent, was a note of fright which had previously been absent. Dr. Bird bent over his ultra-violet search-light and made some adjustments. He handed a helmetlike arrangement to each of his companions and slipped one on over his head.
"I can't see a thing, Doctor," said Carnes in a muffled voice.
"The objects at which you are looking absorb rather than reflect ultraviolet light," said the doctor. "This is a sort of a fluoroscope arrangement, and it isn't perfect at all. However,
