Went out to the outer berg, where there was quite a collection of people, mostly in connection with Ponting, who had brought camera and flashlight.
It was beautifully calm and comparatively warm. It was good to hear the gay chatter and laughter, and see ponies and their leaders come up out of the gloom to add liveliness to the scene. The sky was extraordinarily clear at noon and to the north very bright.
We have had an exceptionally large tidal range during the last three days—it has upset the tide gauge arrangements and brought a little doubt on the method. Day is going into the question, which we thoroughly discussed to-day. Tidal measurements will be worse than useless unless we can be sure of the accuracy of our methods. Pools of salt water have formed over the beach floes in consequence of the high tide, and in the chase of the crabcater to-day very brilliant flashes of phosphorescent light appeared in these pools. We think it due to a small copepod. I have just found a reference to the same phenomenon in Nordenskiold's ‘Vega.’ He, and apparently Bellot before him, noted the phenomenon. An interesting instance of bi-polarity.
Another interesting phenomenon observed to-day was a cirrus cloud lit by sunlight. It was seen by Wilson and Bowers 5° above the northern horizon—the sun is 9° below our horizon, and without refraction we calculate a cloud could be seen which was 12 miles high. Allowing refraction the phenomenon appears very possible.
Wednesday, May 31.—The sky was overcast this morning and the temperature up to −13°. Went out
