ought to have in his memory the approximate variation of the compass at various stages of the journey and to know how to apply it to obtain a true course from the compass. The variation changes very slowly so that no great effort of memory is required.
2. He ought to know what the true course is to reach one depôt from another.
3. He should be able to take an observation with the theodolite.
4. He should be able to work out a meridian altitude observation.
5. He could advantageously add to his knowledge the ability to work out a longitude observation or an ex-meridian altitude.
6. He should know how to read the sledgemeter.
7. He should note and remember the error of the watch he carries and the rate which is ascertained for it from time to time.
8. He should assist the surveyor by noting the coincidences of objects, the opening out of valleys, the observation of new peaks, &c.19
Tuesday, June 13.—A very beautiful day. We revelled in the calm clear moonlight; the temperature has fallen to −26°. The surface of the floe perfect for ski—had a run to South Bay in forenoon and was away on a long circuit around Inaccessible Island in the afternoon. In such weather the cold splendour of the scene is beyond description; everything is satisfying, from the deep purple of the starry sky to the gleaming bergs and the sparkle of the crystals under foot.
