In these days of feverish activity in every avenue of business, when even leisure has come to be observed at a much more accelerated _tempo_ than formerly, speed in locomotion would seem to be the first desideratum, not only on shore but afloat as well. In no ocean service is the truth of this so apparent as in the transatlantic mail and passenger service, the oldest and most constantly progressive, and where at the present time, certainly more than at any former period, the contest for supremacy amongst rival steamship lines has assumed the form of increased speed and enhanced passenger accommodation. The Atlantic service, for these reasons, as well as because it exemplifies more of the fruits which have rewarded the joint labours of the engineer and shipbuilder in improving marine propulsion, may be selected for detailed review. In other ocean services, of course, the achievements of engineering and shipbuilding skill have also been made apparent, and in ways, perhaps, which the Atlantic service does not exhibit. Reference to these will afterwards be made, but attention will meantime be confined to the service stated, and to such considerations of the general progress made in ocean navigation as are necessarily involved in the particular subject. It is needless, in view of the frequency with which the story of ocean steam navigation is told, and especially, considering the scope of the present review, to enter at any length into the details of early service. The first practically successful transatlantic steamers were the _Sirius_ and the _Great Western_, the first a paddle-steamer 170 feet long, 270 horse-power originally constructed to ply between London and Cork, and the latter, a paddle-steamer, 212 feet long and about 440 horse-power, designed and built expressly for the transatlantic service. The _Sirius_ left Cork on the 4th April, 1838, and reached New York on the 22nd; the _Great Western_ left Bristol on the 7th April, three days after the _Sirius_, reaching New York on the 23rd—the time taken being thus 18 days and 15 days respectively. The return voyages of these pioneer long-passage steamers were made in 16 days and 14 days respectively, their performances at once establishing the superiority of steamers, commercially and otherwise, over the sailing ships which had previously for so long been the recognised medium of transit in the Atlantic passenger trade.