The north of Yakutia has long been known to be an immense storehouse of frozen disjointed bones of many hundreds of thousands of large Pleistocene mammals—mammoths, horses, woolly rhinoceroses, bison, musk-oxen— “horned cattle”, as the first Russian travellers called them. Such knowledge had a commercial value, of whichmore will be said below, for the quarrying of mammoth ivory has gone on for many centuries. In quality these tusks, which have lain in frozen ground for tens of millennia, are as good as those of modern African and Indian elephants and are sometimes two or three times larger. For naturalists, the greatest interest lies in the discovery of whole frozen bodies or of skulls and complete skeletons. Study of the position of these bodiesand their morphology and of the contents of their stomachs and intestines may answer the age-old question of why the mammoth (or woolly elephant), together with this rich assemblage of large herbivores, died out. Would even a partial restoration of such previously abundant life be possible there today?

If one is sufficiently bold or foolish to ask why the musk-ox Ovibos moschatus was domesticated, even a superficial review of the available evidence suggests that several answers may be given, depending upon the viewpoint from which the question is posed. I have argued elsewhere (Wilkinson, 1972a; 1973) that the domestication of the musk-ox was inevitable if the exploitation of musk-oxen was to continue in the present century. Because of certain biological and behavioural characteristics, musk-oxen can be exploited in only two ways without endangering their survival or exceeding their capacity to regenerate their numbers: they may be hunted as what I have called a critical resource, by which I mean a resource that is not exploited regularly (including seasonally) or intensively, but without which human survival is difficult or impossible incertain areas and periods; alternatively, musk-oxen may be exploited on a sustained basis for a combination of meat, milk, robes, or qiviur through domestication. Archaeological and ethnographic evidence is consistent with the hypothesis that, as a general rule, musk-oxen were hunted as a critical resource before the arrival of Europeans in the Canadian Arctic.

In 1897–98 I went to lies Kerguelen on a sealing expedition in the sealer Edward, returning to London later in 1898. It was through this that I learned that Carsten Egeberg Borchgrevink was in London preparing an Antarctic expedition. He had served as an ordinary seaman in Antarctic in 1894–95 when H. J. Bull made a voyage to the Ross Sea, making the first landing in Victoria Land.

For several years. Geophysical Survey Systems, Inc has been using an impulse radar system as a shallow subsurface exploration tool for engineering applications. Recently this system has been applied to the measurement of ice thicknesses both on sea-water and fresh-water ice. In the course of a feasibility study performed in December 1972, thebasic operating parameters and limitations of the tool when operated on ice were determined. Following the feasibility study, operational surveys were performed totalling approximately 11 crew-months and covering in excess of 1 500 km of survey route at several locations in the Canadian Arctic. The technique is known as Electromagnetic Subsurface Profiling (ESP), and it can be considered the electromagnetic equivalent of the single-trace acoustic profiling methods used for marine subbottom profiling. In practice, ice-thickness profiling is done by towing a sled-mounted antenna behind a tracked vehicle containing the impulse system (Fig 1). Real-time profile data are displayed graphically on a strip-chart recorder. The data may also be recorded on magnetic tape for later processing and playback.