NO. W.] MECHANICAL COMPOSITION OF SAMPLES. 17 



subsequently takes place, after which it is not long before the clay is deposited 

 in the salt water. 



It might seem natural to assume that the mutual attraction between the 

 clay-particles was due to osmotic action between the salt water surrounding 

 them, and the fresh water enclosed in them from the boiling. For the purpose 

 of investigating this, I boiled clay in salt water of the same concentration 

 as sea-water, and poured the liquid into the various glasses. In connection 

 with this it must be remarked that it is quite impossible to work with 

 perfectly fresh water, as a certain amount of salt is conveyed by the clay; 

 no very marked results can therefore be expected. It appears, however, as 

 far as observation is possible, that the clay sinks with the same rapidity 

 in the various kinds of water, and moreover with the same rapidity with 

 which the clay boiled in fresh water, sinks in salt water. It also appears 

 that in the last experiment the clay always coagulates very much, and 

 that the above-mentioned osmotic action thus cannot be of any great con- 

 sequence. At present it is not possible for me to give any physical explanation 

 of the circumstance. 



If we apply the result of these observations to conditions in nature, we 

 must assume that the clay sinks to the bottom at very different rates, according 

 as it originally comes out into the sea- water in larger or smaller quantities. 

 The clay in the sea generally originates either from the rivers or from coast- 

 erosion; but in the greater part of the polar regions, the glacial ice is an 

 additional important factor. This, however, as already mentioned, is not the 

 case in the region traversed by the Fram. The clay that is carried out by 

 the rivers may generally be assumed to be present in the water in a far 

 greater degree of concentration than that which is produced by coast-erosion. 

 The result of this must be that in the neighbourhood of the great river- 

 estuaries, deposits that are to no small extent argillaceous, must as a rule 

 be formed; and this, as will subsequently be shown, is the case here in a 

 marked degree. It must be assumed that the greater part of the clay-particles 

 the rivers bring with them, will unite when they come out into the sea, down 

 into the less disturbed water-strata, and will sink to the bottom very soon, 

 while only a small quantity will be carried farther out to sea. At other places, 

 on the contrary, a great part of the clay will be carried far away, while 

 only a comparatively small part will be deposited nearer the coast. The 



