At the present time, only Antarctica and Greenland carry ice sheets comparable with the ice sheets that covered vast areas of the Northern Hemisphere as recently as 20 000 years ago. At the time of maximum glaciation, some 300 000 years ago, the volume of ice on earth was three times what it is today, and it covered the northern parts of continents all around the Arctic Ocean. In North America, ice stretched south as far as Kansas; in Europe, it extended down ot the River Thames and the Sudety mountains and covered much of Siberia. Even now, the Antarctic ice sheet covers an area of 12 million km2 and in places reaches depths of more than 4 km. The smaller Greenland ice sheet has an area of 1.8 million km2 and exceeds 3 km in depth.

On 10 May 1971, a federal jury in Alexandria, Virginia, found Mario Escamilla not guilty of second-degree murder on the high seas in the death of another American, Bennie Lightsy. The same jury convicted Escamilla of a lesser offence, involuntary manslaughter on the high seas, and he was sentenced to three years in the custody of the United States Attorney-General, a provision that permits probation after as little as 60 days. In fact, Escamilla has been free on bail pending the hearing of an appeal, brief for which will have been filed by 17 October 1971 to be argued before the Court of Appeals for the Fourth Circuit in late 1971 or early 1972.

Ice navigation in Arctic regions is mainly carried out in four areas:

1. The Baltic Sea, which is the only ice-bound sea where year-round traffic is maintained. Except for the Gulf of Bothnia, all main harbours are kept permanently open, even in hard winters; during mild winters, which on average occur once in five years, year-round traffic is maintained even there. This task is accomplished by using some 20 full-size (above 7 000 SHP) icebreakers (two from Denmark, one from West Germany, six to eight from USSR, seven from Finland, four from Sweden), as well as several hundred ice-strengthened cargo ships.

In this instalment of our list, we see that the Hudson's Bay Company, under the shrewd direction of its overseas governor, George Simpson, quickly recovered from its exhausting struggle with the North West Company and, strengthened by amalgamation with its rival in 1821, began vigorously to push into unknown country both west and east. In the east, the Ungava venture was an attempt, mainly unsuccessful, to develop a fur trade in the interior of the Quebec-Labrador peninsula. And in the west, the exertions of a few hardy men opened the fur-rich country of the Liard River and its tributaries, the Peel River and the region of the Mackenzie River delta, and crossed the Rocky Mountains to the upper drainage of the Yukon River.