The peatlands of the Outer Hebrides are half land, half water. Their surface is a glorious tweed woven from tiny, living sphagnums rich in wildlife, but underneath is layer upon layer of dead mosses transforming into the peat. One can, with care, walk out onto them, but stop and you begin to sink into them. For time immemorial the peatlands have been places – for humans at least – of seasonal habi...