CURRENT-BOTTLES. 



is shown on page 137, can move quite independent of that icewater, to which it originally belongs. 

 Such movements can be caused by the wind and can perhaps also have assisted to carry the surface- 

 water with the bottles towards the South-West. When the bottles nos 1 — 12 were thrown the wind was 

 light, chiefly coming from the South- West, when bottles nos 13—16 were thrown, the wind turned through 

 the South-East to the North, but was continuously very light. The bottles nos 17— 20 were thrown, when 

 the wind was northnorthwesterly of strength 3 (Beaufort). During «Ingolf»s return- voyage from Jan Mayen 

 to Iceland the wind was all the time very light. It is therefore not to be supposed, that the wind 

 can have had any particular influence on the drifting of the bottles. Very little is known about the 

 mean direction of the wind in these waters. It appears however from the meteorological observations, 

 that the wind at the Northern coast of Iceland is on an average easterly during the months of July 

 and August If it may be concluded, that the direction of the wind is usually the same in the Ocean 

 North of Iceland, then the wind will also have contributed to carry the current-bottles inwards 

 towards the North-Eastern coast of Iceland. We must suppose, that the bottles deviate towards 

 the South-East about on 65 Northern latitude and follow the Polar-current towards the Faeroe-Islands. 



The bottles have now arrived at the line of contact between the Gulfstream and the Polar- 

 current We do not know the further course of the last mentioned, whether it runs round a circle in 

 the Western North-Ocean or whether its circular course has even a greater diameter. In the summer 

 of 1896 it could be traced North of the Fseroe-Islands and there is hardly any doubt, that it enters 

 the Eastern part of the North-Ocean. The question now to be decided is whether the bottles can 

 be carried from the Polar-current into the Gulfstream. 



The specific gravity of the bottles was only very little less than that of the water, and as a 

 bottle in this way only offers a very little surface for the action of the wind, it can hardly be sup- 

 posed, that the wind has driven the bottle with a speed worth considering; in accordance herewith it 

 must be supposed, that the wind cannot change the course of the bottle, causing it to go from the 

 Polar-current into the Gulfstream. On the other hand, if it be supposed, that the water, in which the 

 bottle is thrown, sinks down under other water strata, the bottle will not follow the water stratum, 

 to which it belongs, but will pass into the water stratum, which is uppermost. This however can not 

 take place in the present case. The water, in which the bottles were thrown contained 32 — 33 %o 

 salt While this water runs southwards, it is in contact with the cold and somewhat Salter bulk of 

 the icewater and thereby its contents of salt are somewhat increased. Its temperature also increases, 

 the summerheat from the air having more effect than the cold water below. When the bottles have 

 arrived in the neighbourhood of the Atlantic-water, they will then be in icewater, which is a little, 

 but not much, colder than the Atlantic-water. The quantity of salt in this icewater has been some- 

 what increased by its coming into contact with the Salter icewater underneath, and possibly also by 

 its being mixed with Atlantic-water. The specific gravity of the surface-water cannot surpass the spe- 

 cific gravity of the Atlantic- water by any of these processes; the surface stratum of the icewater accor- 

 dingly can not sink under the Atlantic-water and consequently the bottles cannot in this way pass 

 into the Gulfstream. 



The bottles thus being unable to pass the line of contact between the Polar-current and the 

 Gulfstream, we must suppose, that surface-water from the Polar-current can pass over the water of the 



