[Sidenote:  Crowded and vacant islands.]

This is one of the sharp contrasts in island life,—­here density akin to congestion, there a few miles away a deserted reef or cone rising from the sea, tenanted only by sheep or goats or marine birds, its solitude broken only by the occasional crunching of a boat’s keel upon its beach, as some visitant from a neighboring isle comes to shear wool, gather coco-nuts, catch birds or collect their eggs.  All the 500 inhabitants of the Westman Isles off the southern coast of Iceland live in one village on Heimey, and support themselves almost entirely by fishing and fowling birds on the wild crags of the archipelago.[945] An oceanic climate, free contact with the Gulf Stream, and remoteness from the widespread ice fields of Iceland give them an advantage over the vast island to the north.  Only twenty-seven of the ninety islands composing the Orkney group are inhabited, and about forty smaller ones afford natural meadows for sheep on their old red sandstone soil;[946] but Pomona, the largest Orkney has 17,000 inhabitants on its 207 square miles of territory or 85 to the square mile.  The Shetlands tell the same story—­29 out of 100 islands inhabited, some of the holms or smaller islets serving as pastures for the sturdy ponies and diminutive cattle, and Mainland, the largest of the group, showing 58 inhabitants to the square mile.  This is a density far greater than is reached in the nearby regions of Scotland, where the county of Sutherland can boast only 13 to the square mile, and Invernesshire 20.  Here again insularity and contracted area do their work of compressing population.

The causes of this insular density of population are not far to seek.  Islands can always rely on the double larder of land and sea.  They are moreover prone to focus in themselves the fishing industry of a large continental area, owing to their ample contact with the sea.  Shetland is now the chief seat of the Scotch herring fishery, a fact which contributes to its comparatively dense population.  The concentration of the French export trade of Newfoundland fish in little St. Pierre and Miquelon accounts for the relatively teeming population (70 to the square mile) and the wealth of those scraps of islands.  So the Lofoden Islands of Norway, like Iceland, Newfoundland and Sakhalin, balance a generous sea against an ungenerous soil, and thus support a population otherwise impossible.

[Sidenote:  Oceanic climate as factor.]

For these far northern islands, the moderating effect of an oceanic climate has been a factor in making them relatively populous, just as it is on tropical isles by mitigating heat and drought.  The prosperity and populousness of the Bermuda Islands are to be explained largely by the mild, equable climate which permits the raising of early vegetables and flowers for English and American markets.  Like climatic conditions and a like industry account for the 2,000 souls living on the inhabited islands of the Scilly group.  Here intensive horticulture supports a large force of workmen and yields a profit to the lord proprietor.  Syros in the Cyclades fattens on its early spring vegetable trade with Athens and Constantinople.[947]