330 
THE VOYAGE OF THE VEGA. 
[chap. 
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. 
5. In a dust (kryokonite), collected on the inland ice of 
Greenland in the month of July, 1870, there were also found 
mixed with it grains of metallic iron, containing cobalt. The 
main mass consisted of a crystalline, double-refracting silicate, 
drenched throus^h with an ill-smellincf organic substance. The 
dust was found in large quantities at the bottom of innumerable 
small holes in the surface of the inland ice. This dust could 
scarcely be of volcanic origin, because by its crystalline structure 
it differs completely from the glass-dust that is commonly 
thrown out of volcanoes, and is often carried by the wind to 
very remote regions, as also from the dust which, on the 30th 
March, 1875, fell at many places in the middle of Scandinavia, 
and which was proved to have been thrown out by volcanoes 
on Iceland. For, while kryokonite consists of small angular 
double-refracting crystal-fragments without any mixture of 
particles of glass, the volcanic Haga-dust ^ consists almost 
wholly of small microscopic glass bubbles that have no action 
on the polarisation-planes of the light that passes through 
them. 
Similar investigations have since been made, among others. 
1 I use this name because the ash-rain of March 1875 was first observed 
at Haga palace near Stockholm, and thus at the outer limit of the known 
area of distribution of the dust. It was first through the request which 
in consequence of this observation was published in the newspapers, that 
communications regarding singular observations in other quarters should 
be sent to the Swedish Academy of Sciences, that it became known that 
a similar rain had about the same time taken place over a very large part 
of middle Sweden and Norway. The dust however did not fall evenly, - 
but distributed in spots, and at several different times. The distance 
from Stockholm of the volcanoes, where the outbreak took place, is nearly 
2000 kilometres. 
