One would attribute the cause of these colours to metals or minerals of the places where this ice was formed; or of waters of which it was coagulated: but experience teaches me, that the blue ice is the concretion of fresh water, which at first is white, and at length hardens and turns blue; but the greenish colour comes from salt water. It is observed, that if you put the blue ice near the fire and let it melt, and afterwards remove it to a colder place, to freeze again, it does not recover its former blue, but becomes white. From whence I infer, that the volatile sulphur, which the ice had attracted from the air, by its resolution into water, exhales and vanishes. Though the summer season is very hot in Greenland, it seldom causes any thunder and lightning; the reason of which I take to be the coolness of the night, which allays the heat of the day, and causes the sulphureous exhalations to fall again with the heavy dew to the ground. As for the ordinary meteors, commonly seen in other countries, they are visible in Greenland; as the rainbow, flying or shooting stars, and the like. But what is more peculiar to the climate, is the Northern Light, or Aurora Borealis, which in the spring of the year, about the new moon, darts streams of light all over the sky, as quick as lightning, especially if it be a clear night, with such a brightness, that you may read by it as by daylight. At the summer solstice there is no night, and you have the pleasure to see the sun turn round about the horizon all the twenty-four hours; and in the depth of winter they have but little comfort in that planet, and the nights are proportionally long; yet it never is so dark, but you can see to travel up and down the country, though sometimes it be neither moonshine nor starlight: but the snow and ice, with which both land and sea is covered, enlightens the air; or the reason may be fetched from the nearness of the horizon to the equator.