In the interior of the antarctic continent there must be a pole whose temperature is much lower than the frigidity of the arctic poles of cold; the frozen surface of the antarctic continent is in effect much larger than that of Greenland, northern Siberia, or North America. The zone explored by the _Belgica_ lies in a cyclonic region; yet the mean barometric pressure of the year, 744 mm. .7, obtained by a direct observation, is superior by 6 mm. to the theoretical figure obtained by Ferrel for that latitude, and demonstrates that the pressure does not decrease progressively towards the pole, where, on the contrary, there must reign an anticyclone. The absolute minimum was 711 mm. .74, one of the lowest pressures observed on the level of the sea. The maximum pressure was 772 mm. .14. The maximum average monthly variations of the barometer height is 34 mm. .30--a very high figure, which indicates that the tempestuous region extends beyond the polar circle. The barometer height is in the average maximum at the solstices, and minimum at the equinoxes, which shows that in the antarctic there is a direct and very simple relation between the barometric pressure and the sun’s altitude. Winds are frequent and generally violent. Only fifty-five days of calm or very feeble wind were reckoned for a whole year. In the summer, breezes blow mostly from eastern regions; in winter from the western. It is probable that our region is already freed from the direct influence of the circular antarctic zone of western winds. The air is almost constantly saturated with watery vapour, and humidity settles down in the form of fog and snow with remarkable facility. Hoarfrost accumulates in enormous quantities upon every object--upon the ice-pack, the new ice, and even upon the falling snowflakes. During the year we counted two hundred and fifty-seven days of snowfall, and fourteen days of drizzling rain. The sky is almost constantly obscured by a cloak of grayish and low mists, which, when they sometimes happen to disappear, allow a pure sky to be seen, upon which only a few high clouds and very elongated cirri may be noticed. It would not do to generalise these observations and come to the conclusion that the whole antarctic is subject to the climatic régime which we have just described. It is very probable, on the contrary, that in the interior of the antarctic continent the sky must be very often pure, humidity lighter, and snowfalls less frequent. The _Belgica_ was, in fact, imprisoned in a littoral zone, that is, in a zone where came, to be condensed itself, all the humidity brought forth by the winds of the vast regions of a free sea situated farther north. The south wind, or land wind, always had the effect of driving the clouds away and bringing on a dry cold. Optical phenomena were very often noticed. Splendid sunrises and sunsets, parhelia, paraselenæ, and mirage phenomena were remarkable and varied. During the whole winter