Mr. R. M. Ballantyne, in his journal of six years’ residence in the territories of the Hudson’s Bay Company, tells us, that for part of October there is sometimes a little warm, or rather thawy, weather; but after that, until the following April, the thermometer seldom rises to the freezing point. In the depth of winter, the thermometer falls from 30° to 40°, 45°, and even 49° _below zero_ of Fahrenheit. This intense cold is not, however, so much felt as one might suppose; for during its continuance the air is perfectly calm. Were the slightest breath of wind to rise when the thermometer stands so low, no man could show his face to it for a moment. Forty degrees below zero, and quite calm, is infinitely preferable to fifteen below, or thereabout, with a strong breeze of wind. Spirit of wine is, of course, the only thing that can be used in the thermometer; as mercury, were it exposed to such cold, would remain frozen nearly half the winter. Spirit never froze in any cold ever experienced at York Factory, unless when very much adulterated with water; and even then the spirit would remain liquid in the centre of the mass. Quicksilver easily freezes in this climate, and it has frequently been run into a bullet-mould, exposed to the cold air till frozen, and in this state rammed down a gun-barrel, and fired through a thick plank. The average cold may be set down at about 15° or 16° below zero, or 48° of frost. The houses at the Bay are built of wood, with double windows and doors. They are heated by large iron stoves, fed with wood; yet so intense is the cold, that when a stove has been in places red-hot, a basin of water in the room has been frozen solid. PURITY OF WENHAM-LAKE ICE. Professor Faraday attributes the purity of Wenham-Lake Ice to its being free from air-bubbles and from salts. The presence of the first makes it extremely difficult to succeed in making a lens of English ice which will concentrate the solar rays, and readily fire gunpowder; whereas nothing is easier than to perform this singular feat of igniting a combustible body by aid of a frozen mass if Wenham-Lake ice be employed. The absence of salts conduces greatly to the permanence of the ice; for where water is so frozen that the salts expelled are still contained in air-cavities and cracks, or form thin films between the layers of ice, these entangled salts cause the ice to melt at a lower temperature than 32°, and the liquefied portions give rise to streams and currents within the body of the ice which rapidly carry heat to the interior. The mass then goes on thawing within as well as without, and at temperatures below 32°; whereas pure, compact, Wenham-Lake ice can only thaw at 32°, and only on the outside of the mass.--_Sir Charles Lyell’s Second Visit to the United States._ ARCTIC TEMPERATURES.