812 



they do not seem to flow in any direction favourable to the imnii- 

 gration. As pointed out by Ostenfeld (64, p. 115) a broad arm of 

 tiie Gulf Stream flows south east round the islands and seems to 

 prevent all immigration from Europe. As it comes from the open 

 Atlantic and has not touched any country after the West Indies and 

 tropical North America, it can, as Ostenfeld says, only carry tropical 

 fruits and seeds ^ These circumstances are seemingly unfavourable, 

 and Ostenfeld also declares, that in his opinion the current can 

 never carry species that will thrive in the Fasroes. 



This is however scarcely quite right; even if the circumstances are 

 far from favourable, it seems to me it cannot be denied that marine 

 algae, which will thrive at the Faeroes, can be carried there by cur- 

 rents. If we look at one of the latest of the current maps of the 

 northern part of the Atlantic, as for instance Ryder's (73, table 11) 

 which represents the seas between Norway, Scotland and Green- 

 land, and of which flg. 162 represents a photographic reproduction, 

 it must be acknowledged, that as to the parts of the British Isles 

 which are nearest to the Faeroes, the direction of the current is 

 anything but favourable, as it flows from the Faeroes in an almost 

 straight line towards the Shetland Isles. Circumstances are how- 

 ever totally different as to the west coast of Ireland. 



In order to understand this, an ordinary, theoretical map of 

 the currents is not sufficient; one must study a detailed chart, for 

 instance, the excellent »Monatskarte fiir den Nordatlantichen Ozean« 

 prepared by the » Deutsche Seewarte«, on which are indicated all 

 the directions of the currents observed during one month ^. Also 

 in a paper on Rockall (Notes on Rockall Island and Bank etc. 

 Transactions of the Royal Irish Academy, vol. 31, Dublin 1896 — 1901) 

 the observed directions of the currents (all possible directions!) and 



^ Such fruits and seeds are frequently washed ashore on the Faeroes. Lyngbye 

 even mentions this in »Tentamen Hydrophytologise« p. 60. I myself have also found 

 and received from inhabitants of the Faeroes fruits and seeds of Cocos, Entada giga- 

 lobiiim and Guilandina, all well known from the beach woods of the West Indies. 



^ In order to prevent any misunderstanding, I may give a report of what 

 Commodore G. Holm, the director of the chart-archives, has kindly communicated 

 to me, concerning the meaning of the arrows (compare figs. 163 — 4). sTlie arrows 

 indicate the observed directions of the currents. They are most likely compiled 

 from the journals of ships, and are the mean of the directions caused by a cur- 

 rent. Most likely these directions are immediately due to the wind, but in this 

 they do not differ from other currents, for most currents are originally produced 

 by the agency of the wind. The arrows must indicate surface currents extending 

 down more than several feet, several fathoms at least. 



