text:  All the comparatively fertile districts in the south of Arabia in fact are even more completely insulated by the deserts and barren mountains of the interior on one side than by the sea on the other--inasmuch as easier access would be gained by an invader even by the dangerous and difficult navigation of the Red Sea than by a march through a region where the means of subsistence do not exist and where the Bedoweens by choking or concealing the wells might in a moment cut off even the scanty supply of water which the country affords