In 1772, Captain Cook, who had already done so much to reveal the southern hemisphere to the knowledge of man, left the Cape of Good Hope with two ships, the _Resolution_ and the _Adventure_, in search of the continent believed to exist somewhere beyond the regions hitherto visited. In 48° 41' S. latitude, and 18° 24' E. longitude, a sudden fall in the temperature from 67° to 38° Fahr. was experienced. On the following day an iceberg, fifty feet in height and nearly half a mile in length, was sighted. The course was continued to the south, but the third day after sighting the first berg the sea had become so full of ice that no further progress to the south was possible, although the latitude was only 54° 50' S., the corresponding latitude in the northern hemisphere being that of the city of Hull. Skirting the ice-packs and working always to the southward, the vessels managed to reach 55° 16' S. during the next three days, some few seals, penguins, and other birds being seen on the floating ice as the ships passed. The temperature was never above freezing, the sails were frozen and the rigging covered with icicles. The fact that the ice was found to be composed of fresh water, convinced Cook that there must be land still further to the south, lying behind the ice-floes. He, therefore, kept on to the east, always sailing as far to the south as the line of the ice permitted. In reality, he was sailing round the Antarctic, from west to east, skirting along the ice limit. In January 1773 the vessels were in 61° S. and 139° E. longitude. A month later he was nearly five hundred miles to the south of the course Tasman had sailed when he discovered Tasmania, but still no land was seen amongst the ice. This being the summer season in the southern hemisphere, it was necessary to seek winter quarters to the north if the ships were to escape imprisonment in the ice for the season. After a winter passed in the Pacific Ocean, Captain Cook took his ships again to the south, towards the end of the year, and by January 30, 1774, they were in 71° 10' S. latitude and 106° 54' W. longitude. Further progress to the south was barred by a line of high ice cliffs. Describing the circumstances Captain Cook wrote:--