were marooned here from a Portuguese ship with a supply of seed and cattle.  They proved industrious and had cultivated a good deal of the land when four years later they were removed to Portugal.  The next inhabitants were a few slaves of both sexes who escaped from a slave ship that had stopped here for wood and water.  These multiplied, worked and restored the overgrown plantations of their predecessors, till a Portuguese vessel about twenty years later was sent to exterminate them.  A few escaped to the woods, however, and were found there in prosperity in 1588.[910] From 1815 till 1821 St. Helena was the prison of Napoleon.

Many of these penal islands seem chosen with a view to their severe or unhealthy climate, which would forever repel free immigration and therefore render them useless for any other purpose.  This is true of the French Isles du Salut off the Guiana coast, of Spanish Fernando Po in the Gulf of Guinea, of the Andaman and Nicobar Islands, notoriously unhealthy, which receive the criminals of British India,[911] and of numerous others.  A bleak climate and unproductive soil have added to the horror of exile life in Sakhalin, as they overshadowed existence in the Falkland Islands, when these were a penal colony of Spain and later of Argentine.[912]

[Sidenote:  Island prisons for political offenders.]

In the case of political offenders and incorrigibles, the island prison is as remote and inaccessible as possible.  The classic example is Napoleon’s consignment to Elba and subsequently to St. Helena, whence escape was impossible.  Spain has sent its rebellious subjects, even university professors of independent views, to Fernando Po in the Gulf of Guinea and Teneriffe in the Canaries.[913] Russian political offenders of the most dangerous class are confined first in the Schluesselberg prison, situated on a small island in Lake Ladoga near the effluence of the Neva.  There they languish in solitary confinement or are transferred to far-off Sakhalin, whose very name is taboo in St. Petersburg.[914] During our Civil War, one of the Dry Tortugas, lying a hundred miles west of the southern point of Florida and at that time the most isolated island belonging to the American government, was used as a prison for dangerous Confederates; and here later three conspirators in the assassination of President Lincoln were incarcerated.[915] Far away to the southeast, off the coast of South America, are the Isles du Salut, a French penal station for criminals of the worst class.  The Isle du Diable, ominous of name, lies farthest out to sea.  This was for five years the prison of Dreyfus.  Its other inhabitants are lepers.  Isles of the cursed indeed!

[Sidenote:  Islands as places of survival.]