736 



SCIENCE. 



[Vol. II., No. 44. 



My companion on that occasion, Professor Berggreii, 

 discovered tliat tliis substance formed the substratum 

 of a peculiar ice-flora, consisting of a quantity of dif- 

 ferent microscopical plants (algae), of which some 

 are even distributed beyond the clay on tlie ice itself, 

 and -which, in spite of their insignificance, play, be- 

 yond doubt, a very important part in nature's econo- 

 my, from the fact that their dark color far more 

 readily absorbs the sun's heat than the bluish-white 

 ice, and thereby they contribute to the destruction 

 of the ice-sheet, and prevent its extension. Un- 

 doubtedly we have in no small degree to thank these 

 organisms for the meltnig-away of the layer of ice 

 which once covered the Scandinavian peninsula. I 

 examined the appearance of this substance in its re- 

 lation to geology, and demonstrated, — 



1. That it cannot have been waslied down from the 

 mountain ridges at the sides of the glaciers; as it was 

 found evenly distributed at a far higher elevation 

 than that of the ridges on the border of the glaciers, 

 as well as in equal quantity on the top of the ice- 

 knolls as on their sides or in the hollows between 

 them. 



2. That neither had it been distributed over the 

 surface of the ice by running water, nor been pressed 

 up from the hypotlietical bottom ' grovmd ' moraine. 



3. That the clay must therefore be a sediment from 

 the air, the chief constituent of wliich is probably 

 terrestrial dust spread by the wind over the surface 

 of the ice. 



4. That cosmic elements exist in this substance, as 

 It contained molecules of metallic iron which could 

 be drawn out by the magnet, and which, under the 

 blowpipe, gave a reaction of cobalt and nickel. 



Under these circumstances, the remarkable dust 

 which I have named ' kryokonite,' i.e., ice-dust, ob- 

 tained a great scientific interest; particularly as the 

 cosmic element, viz., the matten deposited from 

 space, was very considerable. Even later students 

 who have visited the inland ice have observed this 

 dust, but in places surrounded by mountains, from 

 wliicli it might with more probability have been 

 washed down. They have, therefore, and without 

 having examined Professor Berggren's and my own 

 researches of 1S70, paid little attention to the same; 

 while the samples brought home by Dr. N. O. Hoist 

 from South Greenland in 1880 were not very exten- 

 sive. 



But now Dr. Berlin brings home from a great vari- 

 ety of places ice algae, which, I feel convinced, will 

 contribute fresh materials to our knowledge of the 

 flora of the ice and snow. For my own part, I have 

 re-examined my first researches of the kryokonite, 

 and they are fully corroborated. Everywhere where 

 the snow from last winter has melted away, a fine 

 dust, gray in color, and, when wet, black or dark 

 brown, is distributed over the inland ice in a layer 

 which I should estimate at from 0.1 to 1 millimetre 

 in thickness, if it was evenly distributed over the en- 

 tire surface of the ice. It appears in the same quan- 

 tity in the vicinity of the ice-border surrounded by 

 mountains as a hundred kilometres inland ; but in the 

 former locality it is mixed with a very fine sand, gray 



in color, which may be separated from the kryoko- 

 nite. Farther inland this disappears, however, com- 

 pletely. Gravel or real sand I have never, in spite 

 of searching for thetn, discovered in tlie kryokonite. 

 The kryokonite always contains very fine granular 

 atoms, which are attracted by the magnet, anil which, 

 as may be demonstrated by grating in an agate mor- 

 tar and by analysis luider the blowpipe, consist of a 

 gray metallic element; viz., nickel iron. In general, 

 the dust is spread equally over the entire surface of 

 the ice. Thus it was found everywhere where the 

 snow from the previous year had melted away; while, 

 to judge by apiiearances, there seemed to be little dif- 

 ference between the quantity found near the coast, 

 and in the interior. The dust does not, however, 

 form a continuous layer of clay, but has, by the melt- 

 ing of the ice, collected in cavities filled with water, 

 which are found all over the surface. These are 

 round, sometimes semicircular, one to three feet in 

 deptli, with a diameter of from a couple of millime- 

 tres to one metre or more. At the bottom a layer of 

 kryokonite one to four millimetres in thickness is 

 deposited, which has often, by organisms and by the 

 wind, been formed into little balls; and everywhere 

 where the original surface of the ice has not been 

 changed by water-currents, the cavities are found so 

 close to each other that it would be very difiicult to 

 find a spot on the ice as large as the crown of a liat 

 free from them. In the niglit, at a few degrees be- 

 low freezing-point, new ice forms on these hollows; 

 but they do not freeze to the bottom, even under the 

 severest frost, and the sheet which covers them is 

 never strong enough to support a man, more particu- 

 larly if the hole is, as was the case during half oiu- 

 journey, covered with a few inches of newly-fallen 

 snow. 



The kryokonite cavities were perhaps more danger- 

 ous to our expedition than any thing else we were ex- 

 posed to. We passed, of course, a number of crevasses 

 without bottom as far as the eye could penetrate, and 

 wide enough to swallow up a man ; but they were 

 ' open,' i.e., free from a cover of snow, and oonld 

 with proper caution be avoided; and the danger of 

 these could further be minimized by the seiuling of 

 the two-men sledges in front, and, if one of tlie men 

 fell into the crevasse, lie was supported by the run- 

 ners and the alpenstock, which alw.ays enabled him to 

 get up on the ice again. But this was far from being 

 the case with the liryokonite hollows. These lie, with 

 a diameter just large enough to hold the foot, as close 

 to one another as the stumps of the trees in a felled 

 forest; and it was therefore impossible not to stumble 

 into them at every moment, which was the more an- 

 noying as ithappened just when the foot was .stretched 

 for a step forward, and the traveller was precipitated 

 to the ground with his foot fastened in a hole three 

 feet in depth. The worst part of our jouiiiey was 

 four days outward and three days of the return; and 

 it is not too much to say that each one of ns, during 

 these seven days, fell a hundred times into these cavi- 

 ties, viz., for all of us, seven thousand times. I am 

 only surprised that no bones were broken, — an acci- 

 dent wliich would not only have brought my explo- 



