Chap. V.]
MAGNETIC OBSERVATIONS ON ICE.
147
1841
ployed for the effect of the ship's iron were still to be depended upon. We were at this time in latitude 63º 23′ S., longitude 149º 58′ W., having penetrated the pack nearly one hundred miles in a south-west direction. The magnetic observations on the ice agreed very satisfactorily with those made on board the ships; by them we found the magnetic dip to have increased to 77º 23′ S., and the variation to 20º 2′ E.; on board the Erebus the dip was 77º 25′ S., the variation 20º 14′ E.
The ice slackened in the afternoon, and we pushed the ships nearly twenty miles further to the S.S.W. by midnight, when we were again stopped.
We made considerable progress next morning, Dec. 20.by taking advantage of every opening that occurred, although the thick fog, which came on early in the forenoon, prevailed throughout the day. Numerous whales, seals. Cape pigeons, and white petrel were seen, and two or three flocks of an elegant little tern were observed flying to the south-westward. At noon we were in lat. 63º 47′ S., long. 151º 34′, W.; in the course of the afternoon, the ice again closed, and prevented our getting any further; we tried for soundings, and struck ground in one thousand seven hundred fathoms. The temperature of the sea at 900 fathoms was 39º.8; at 750 fathoms, 39º.6; at 600 fathoms, 40º; at 300 fathoms, 38º.4; at 150 fathoms, 35º.6; and at the surface, 30º. The experiment at 450 fathoms failed through an acci-