_Thursday, June_ 15.--Keen cold wind overcast sky till 5.30 P.M. Spent an idle day.
Jimmy Pigg had an attack of colic in the stable this afternoon. He was taken out and doctored on the floe, which seemed to improve matters, but on return to the stable he was off his feed.
This evening the Soldier tells me he has eaten his food, so I hope all be well again.
_Friday, June_ 16.--Overcast again--little wind but also little moonlight. Jimmy Pigg quite recovered.
Went round the bergs in the afternoon. A great deal of ice has fallen from the irregular ones, showing that a great deal of weathering of bergs goes on during the winter and hence that the life of a berg is very limited, even if it remains in the high latitudes.
To-night Debenham lectured on volcanoes. His matter is very good, but his voice a little monotonous, so that there were signs of slumber in the audience, but all woke up for a warm and amusing discussion succeeding the lecture.
The lecturer first showed a world chart showing distribution of volcanoes, showing general tendency of eruptive explosions to occur in lines. After following these lines in other parts of the world he showed difficulty of finding symmetrical linear distribution near McMurdo Sound. He pointed out incidentally the important inference which could be drawn from the discovery of altered sandstones in the Erebus region. He went to the shapes of volcanoes:
The massive type formed by very fluid lavas--Mauna Loa (Hawaii), Vesuvius, examples.
The more perfect cones formed by ash talus--Fujiama, Discovery.
The explosive type with parasitic cones--Erebus, Morning, Etna.
Fissure eruption--historic only in Iceland, but best prehistoric examples Deccan (India) and Oregon (U.S.).
There is small ground for supposing relation between adjacent volcanoes--activity in one is rarely accompanied by activity in the other. It seems most likely that vent tubes are entirely separate.
_Products of volcanoes_.--The lecturer mentioned the escape of quantities of free hydrogen--there was some discussion on this point afterwards; that water is broken up is easily understood, but what becomes of the oxygen? Simpson suggests the presence of much oxidizable material.
CO_2 as a noxious gas also mentioned and discussed--causes mythical 'upas' tree--sulphurous fumes attend final stages.