April 1.Favoured by a moderate breeze from the southwest, we shaped our course for the focus of maximum total intensity, as indicated by the general course of the isodynamic lines in Colonel Sabine's chart of the southern hemisphere, lying in about lat. 47° S. and long. 140° E., a position which we had not been able to attain during our run from Kerguelen Island to Van Diemen's Land, but which we now had in our power of approaching with greater advantage, by a course directly across the isodynamic oval surrounding it. The last iceberg was seen from the mast-head this morning when in lat. 53° 30′ S.: it was of small size.
The wind increased to a strong breeze, and we had a good run during the night.
April 2.Being nearly calm in the forenoon of the next day the boats were lowered down, and soundings were obtained in one thousand four hundred and forty fathoms: our latitude at the time being 52° 10′ S. and long. 136° 56′ E. The weight employed on this occasion was 336 lbs., and the instant of each hundred fathoms passing off the reel was taken as usual, and is given on the following page, by which the increased friction of the line throughout the descent of the weight may be observed. The observations of the temperature which follow serve to show we had crossed the line of mean temperature since our experiments on the 30th March, and that the influence of the sun's heat was here felt to the depth of 450 fathoms.
