SHADOW DIAL AT THE POLE
At the Pole, a man's shadow is about the same length for every hour of the double day. When a shadow line is drawn in the snow from a man's foot in a marked dial, the human shadows take the place of the hands of a clock and mark the time by compass bearing. The relative length of these shadows also give the latitude or a man's position north or south of the equator. When during two turns around the clock dial, the shadows are all of about equal length, the position of the earth's axis is positively reached—even if all other observations fail. This simple demonstration is an indisputable proof of being on the North Pole.
In the northward march we did not stay up all of bedtime to play with shadow circles. But, at this time, to E-tuk-i-shook the thing had a spiritual interest. To me it was a part of the act of proving that the Pole had been attained. For only about the Pole, I argued, could all shadows be of equal length. Because of this combination of keen interests, we managed to find an excuse, even during sleep hours, to draw a line on our shadow circle.
Here, then, I felt, was an important observation placing me with fair accuracy at the Pole, and, unlike all other observations, it was not based on the impossible dreams of absolutely accurate time or sure corrections for refraction.
HOW THE ALTITUDE OF THE SUN ABOVE THE HORIZON FIXES THE POSITION OF THE NORTH POLE
The exact altitude of the sun at noon of April 22, 1908, on the pole, was 12° 9ʹ 16ʺ, but owing to ice-drift—the impossibility of accurate time—and unknown error by refraction, no such pin-point accuracy can be recorded. At each hour the sun, circling about the horizon, cast a shadow of uniform length.
At the place where E-tuk-i-shook and I camped, four miles south of where I had left Ah-we-lah with the dogs, only two big ice hummocks were in sight. There were more spaces of open water than at our first camp. After a midnight observation—of April 22—we returned to camp. When the dogs saw us approaching in the distance they rose, and a chorus of howls rang over the regions of the Pole—regions where dogs had never howled before. All the scientific work being finished, we began hastily to make final preparations for departure.