"Wouldn't it be a good idea to prepare angles at different times of the day, in the forenoon and in the afternoon?"
"That is the proper thing to do, so as to enable you to make observations from the angles at all times. A chart could then be made from that which would show at a glance what the value of each angle is."
"We shall certainly have to do that; but what interests me as much is, to know how far we have traveled. Can we also tell that by the sun?"
"Yes; but to do so will depend on the accuracy of the observation. For the present, with only a single instrument, the bevel square, we must be content to make our calculations exactly at midday, when the shadow points due south. Or, in the northern hemisphere, when the shadow points due north. I want you, in the meantime, to think over that problem, as it is a very interesting one, and we will take it up when we are not so tired."
CHAPTER IV
THE DISAPPEARANCE OF THE YAKS
It was a relief to get on fairly even ground again, where it would not be necessary to make turns and twists around all sorts of obstructions, to say nothing of ravines and water courses. On the evening of the fifteenth day, calculations showed that they were halfway back from the point farthest west, but they still had no knowledge of their distance from the sea, which undoubtedly was to the east, or, possibly, northeast. West River flowed to the north, and all the streams crossed flowed north or northeasterly, how far, it was impossible to say.
Two days afterward the scene changed somewhat. There had been little wind during the journey thus far; but now breezes sprang up for two successive days, at about four in the afternoon, which came from the north.
"I think the sea is not far away."