With the famous scientist and his assistant as passengers, the _Denver_ steamed at her best speed across the Atlantic. As soon as New York harbor was cleared, Dr. Bird charted the course. Captain Evans raised his eyebrows when he saw the course laid out, but his orders had been positive. Had Dr. Bird ordered him to steam at full speed against the shore, he would have obeyed without question. The _Denver_ avoided the usual lanes of traffic and bore to the north of the summer lane. Not a vessel was sighted in the eight days which elapsed before the Faroe Islands came in sight on the starboard bow. The _Denver_ bore still more to the north and skirted around North Cape five days later. At Cape Kanin she headed south into the White Sea. Surprisingly little ice was encountered. When Captain Evans mentioned this, Dr. Bird pointed out to him that it was August and that the days were still lengthening. Once in the White Sea, the _Denver_ was made ready for instant action. A huge amphibian plane was hoisted in sections from the hold and mechanics started to assemble it. Dr. Bird spent most of his time working on some instruments he had assembled in the radio room. "This is an ultra-short wave detector," he explained to Carnes. "It will receive vibrations to the lowest limit of waves that we have ever been able to measure. The X-ray is high on the scale and even the cosmic ray is far above its lower limit of detection. We are hunting for an electro-magnet, the largest and strangest electro-magnet that has ever been constructed. Perhaps it would be more accurate to say that we are seeking for a generator of magnetic force. It does not generate the ordinary magnetism which attracts iron and steel, nor the special type of magnetism which we call gravity, but something between the two. It attracts the sun enough to disturb the tilt of the earth's axis, but not enough to pull the earth out of its orbit. Such a device should give out a wave that can be detected, if we get a receiver delicate enough and operating on the right wave length." * * * * * He spent hours improving and refining the apparatus, but in the end he confessed himself beaten. "It's no use, Carnes," he said the day after Cape Kanin faded from view to the north. "Either the apparatus we are seeking gives out no wave that we can detect or my apparatus is faulty. Luckily we have other things to guide us." "What are they, Doctor?"