Before we were up next morning "The Curlew" was on her way.
A great number of small islands, not even indicated on our chart, compelled us to veer to the southward during the forenoon.
For several days the needle of our compass had been giving us some trouble by its strong inclination to dip. Three times, since starting, we had been obliged to move the sliding weight out a little on the bar. The farther north we got, the stronger was the tendency of the north pole, or end of the needle, to point downward, and the south pole to rise up correspondingly. By running the sliding weight out a little toward the south pole, its leverage was increased, and the parallel position restored. This was what Capt. Mazard was doing when we went on deck that morning.
"How do you account for this dipping of the needle?" he asked Raed.
"By the present theory of magnetism, the earth itself is considered to be a magnet with two poles," replied Raed. "These poles attract and repel the corresponding poles of a magnetic needle, just as another large needle would. The nearer we get up to the north magnetic pole of the earth, the more the pole of our needle is pulled down toward it. We're not such a great distance from it now. What's our latitude this morning?"
"63° 27'."
"Capt. Ross, in the expedition of 1829, made out the earth's north magnetic pole to be in 70° north latitude, farther west, in the upper part of Hudson Bay. At that place he reports that a magnetic needle, suspended so that it turned easily, pointed directly downward."
"We've got a needle hung in a graduated scale downstairs," remarked Kit.
We had nearly forgotten it, however.
"Bring it up," said Raed.