The purpose of this paper is to describe the facilities that have been developed forconducting biological studies through the permanent, or nearly permanent, sea ice cover ofMcMurdo Sound, Antarctica.

The earliest Antarctic expeditions into inshore areas casually observed and collectedbiota either from shipboard and small boats on rareoccasions when ice conditions were favourable, or from holes or cracks in the ice when temperatures were high enough to preventrapid refreezing. The facilities and techniques described here have evolved since 1958 from similar crude and time-consuming techniques to sophisticated, efficient operations that can now be carried out continuously through ice cover of less than 1 m to over 4 m.

During the austral summer of 1963–64 an investigation was started near “Mc-Murdo” on the diving habits of the Weddell Seal (Leptonychotes weddelli). The Weddell Seal was selected for this investigation because of some unique characteristics of its behaviour and because of the environment in which it occurs at McMurdo Sound, Antarctica. For eight to ten months of each year the sea ice provides a solid cover except for tidal cracks along the coast, pressure cracks between old and new ice, and scattered holes cut for oceanographic work. This gives the seals rather specific areas where they may surface in order to breathe. When they visit these breathing holes, instruments may be attached to them with a high probability that they will revisit the same hole and allow the investigator to remove the instrument. With this knowledge of the Weddell Seal' diving behaviour, it was my intention not only to gain some idea of the maximum diving epths and submergence times, but also to obtain information on such things as rates of descent and ascent, cruising depths and submarine orientation patterns. To determine these various parameters two types of instrument were needed, a depth-time device for recording dive profiles and a smaller, more easily attached unit that could be used to measure maximum depth of dives of a large number of seals.

In May 1956, an article in this Journal described the mapping of the Falkland Islands Dependencies up to that date (Leay, 1956). In March 1962, that part of the Dependencies lying south of 60° S was re-named British Antarctic Territory. This is an account of the maps of both the Dependencies and the Territory that have been published by the Directorate of Overseas Surveys* since 1956 and of the methods that have been used in their production.

The United States Army Research Support Group (USARSG), with headquarters at “TUTO”, provided all logistic support for the second phase of a co-operative programme of field work on the ice sheet of north-west Greenland designed to evaluate radio echo sounding techniques, to compare results with seismic and gravity surveys, and to continue measurements of strain rate in the ice sheet.

During the past few years, interest in the physicochemical properties of ice has expanded considerably (Gorham, 1958; Sugawara, 1961; Coachman, Hemmingsen & Scholander, 1956; Langway, 1962). Little, however, is known of the chemical composition of precipitation in the polar regions or of the chemical composition of different types of ice. Consequently, it is thought that the following information, compiled as a part of a much larger chemical study of several Antarctic lakes, might be of some interest to students of chemical meteorology and to those workers investigating the physical properties of ice.

In September 1840, the whaling ship Hope, Captain Brighton, was cruising beyond Cape Horn in the south polar sea. One evening a storm drove her up against icefields and icebergs forming a wide roadstead. About half a nautical mile away rose an interminable line of high, snow-covered mountain peaks; everything was frozen, and in that direction the ocean was obviously closed. Meanwhile the sea was calm in the wide basin and Hopewas no longer in danger of being hurled against the edge of the ice; nor were there any more floating icebergs as they all had formed one continuous mass. But the captain was still on his guard and the crew was ready to use the first favourable wind, which in September in these latitudes usually gets up around midnight. If they stayed too long in this ice harbour the icebergs might start moving close together and wedge the whaling ship in until the weather became milder—or for ever.