The sand is the great enemy here.... The sand drifts like snow, and sometimes the lower story of a house is concealed by it, though it is kept off by a wall. The houses were formerly built on piles, in order that the driving sand might pass under them.... There was a schoolhouse, just under the hill on which we sat, filled with sand up to the tops of the desks, and of course the master and scholars had fled. Perhaps they had imprudently left the windows open one day, or neglected to mend a broken pane.