It is sea-borne trade which makes a Mercantile Marine. It is the great coalfields conveniently near big harbours that have helped to build up the modern British marine after her shipping was temporarily eclipsed by the American. The development of the world consequent on the coming of the industrial age, the great increase of overseas trade therefrom resulting, caused a loud and universal call for cheap maritime carriage. The steamer satisfied that call, for the reason that she was built economically near to the coalfields, and economically propelled because she had cheap coal. She could therefore afford to carry goods cheaply. Then, as we have also seen, this tramp is the forerunner of the liner, and so the story goes on like a stone gathering momentum as it comes down the mountain. So it all depends on cheap fuel quite as much as on cheap labour. The Scandinavians have had the latter for years, but it never enabled them to build up such a merchant fleet as one might have expected. The world’s greatest shipping centre to-day is the Port of London, notwithstanding the great set-back it received during the war, when the presence of German submarines in the English Channel diverted much of its ancient trade to western ports. Had it not been for the possession of an enormous merchant fleet, consisting of a large proportion of small and moderate-sized steamers, the Allied cause would most certainly have been lost, irrespective of the Army in the field or the Navy at sea. The British and German blockades, though exerted in the one case by big ships and in the latter by submarines, had the same effect: the paralysing of the merchant fleet. Take the blockade away and the war could have gone on as long as a couple of men were alive. The pivot of the whole thing is therefore the merchant ship, and she in turn depends on her fuel. The fuel of the future will be oil, and you will find only a minority of experts to deny this. Whether aircraft will ever become the principal passenger-carriers over the world is possible, but remote. For the carriage of goods the dependence will remain on merchant shipping, and one of the incentives to the use of oil-fuel will be brought about by increased competition. Oil is the more economical fuel, for the reason that, other things being equal, one ton of oil-fuel as now used in Diesel engines drives a vessel three times as far as one ton of coal burnt under the boilers of a steamship. And yet oil is twice as efficient as coal when the ship has water-tube boilers and geared turbines. This is the statement of Sir Westcott Abell, the Chief Ship Surveyor of Lloyd’s Register. The biggest liners have now been converted into oil-burning, and it is conceivable that before long we may have Diesel-engined Atlantic leviathans instead of steamers. The absence of boilers will mean more room for passengers and cargo, therefore increased earning capacity.