But the Portuguese, unfortunately, seem quite blind, even to their own interests; and they cannot perceive, that if they could work coal-mines, they would employ a large population, circulate wealth throughout their territory, and attract a considerable and improving commerce to their port. But then their slave-trade would be ruined: and they are not even wise enough in their own generation to perceive, that out of its very ashes would gradually spring up the healthy and vigorous plant of commerce, upon an extensive scale, not only with foreign parts, but with the native tribes of Africa. These, however, are now continually desolated by the scourge of war and slavery. But they would soon learn to value peace and peaceful arts, and the taste for new articles of manufacture would grow gradually into wants, and wants in course of time give birth to the wish for luxuries. Far above all the profits of the traffic in human beings, would then become the fruits of wholesome trade; the country would advance, instead of being driven back; and the welfare of the community and of the government be simultaneously promoted. New regulations respecting trade would in the first instance be indispensable, as at the present time the commandants or little governors of all the minor Portuguese settlements are themselves allowed to trade, and often are the principal, or in a manner the only, merchants in the place. This alone must destroy all healthy competition, the soul of commerce. But, were trade placed upon a proper footing, and coal likely to become an article of demand, it would easily be exported to the Cape, Mauritius, and up to Aden for the Bombay steamers, and to numerous other parts, in which the demand for coal is yearly increasing, and likely to become almost unlimited. I have here rather assumed that coal will be found in large quantity than proved it; but sufficient has been said to point out the great probability of its existence upon that coast in more places than one, and the question involves such important consequences that it deserves the fullest investigation. It was at one time thought that coal would be found in some one of the Comoro islands before alluded to, at the northern extremity of the Mozambique Channel; and the Nemesis was directed, at all events, to touch there on her way, for the purpose of inquiring into its eligibility as a depôt, and place of refreshment for steamers. The distance of the nearest of the Comoro islands, Mohilla, from Mozambique, is scarcely two hundred and fifty miles; and from thence to Johanna, which is the principal one, and the place of residence of the sultan or ruler of the islands, is about thirty miles. Johanna lies as near as possible in the middle of the Channel, between Madagascar and the mainland of Africa, just where it widens into the open sea.