As this question can be answered with the greatest ease and certainty by investigations in the Polar regions, I shall here, for the guidance of future travellers, enumerate some discoveries of a like nature which have been made by me, or at my instance.
1. In the beginning of December, 1871, there happened at Stockholm an exceedingly heavy fall of snow, perhaps the heaviest which has taken place in the memory of man. Several persons perished in the snow in the immediate neighbourhood of Stockholm. During the last days of the snowfall I had about a cubic metre of snow collected and melted in a vessel. It left a residue of black powder, which contained grains of metallic iron that were attracted by the magnet.
2. In the middle of March, 1872, a similar investigation was made by my brother, KARL NORDENSKIÖLD, in a remote forest settlement, Evois, in Finland. Here, too, was obtained, on the melting of the snow, a small residuum, consisting of a black powder containing metallic iron.
[Illustration: SECTION OF THE UPPER PART OF THE SNOW ON A DRIFT-ICE FIELD IN 60° N.L. One-half the natural size. ]
3. On the 8th August and 2nd September of the same year, I examined, north of Spitzbergen, in 80° N.L., and 13° to 15° E.L., the layer of snow that there covered the ice. The nature of this layer is shown by the accompanying woodcut, in which 1, is new-fallen snow; 2, a layer of hardened old snow, eight mm. in thickness; 3, a layer of snow conglomerated to a crystalline granular mass; and 4, common granular hardened snow. Layer 3 was full of small black grains, among which were found numerous metallic particles that were attracted by the magnet, and were found to contain iron, cobalt, and possibly nickel also.
4. On the melting of 500 gram. hail, which fell in Stockholm in the autumn of 1873, similar metallic particles containing cobalt (nickel) were obtained, which, in this case, might possibly have come from the neighbouring roofs, because the hail was collected in a yard surrounded by houses roofed with sheet-iron painted red. The black colour of the metallic particles enclosed in the hail, their position in the hail, and finally, the cobalt they contained, however, indicate in this case too, a quite different origin.