The existence of sulphuretted hydrogen in great quantities below loo fathoms, the extensive chemical precipitation of calcium carbonate, the stagnant nature of its deep waters, and the absence of deep-sea life are conditions which make it impossible to discuss it along with the physical and biological conditions of the Mediterranean proper.
Thus the occurrence of blind animals in caves and in the deep sea was a fact which Darwin himself regarded as best explained by the atrophy of the organ of vision in successive generations through the absence of light and 1 Weismann, Vererbung, &c. (1886).
The deep-sea fishery attracts hundreds of boats from the north of Scotland, and most of the catch is cured for the English, German and Dutch markets.
Distilling however prospers, and the town is important not only as regards its shipping and the deep-sea fishery, but also as a distributing centre for the islands and the seat of the superior law courts.
The chief industries include coast and deep-sea fisheries, shipbuilding, tanning, the making of cod-liver oil and fish-curing.