"ONE evening-twilight in spring, a young English student, who had wandered northwards as far as the outlying fragments of Scotland called the Orkney and Shetland Islands, found himself on a small island of the latter group, caught in a storm of wind and hail, which had come on suddenly. It was in vain to look about for any shelter; for not only did the storm entirely obscure the landscape, but there was nothing around him save a desert moss."