The visitor to the late Naval Exhibition interested in shipping will have remarked at each of the several exhibits of the great firms a model of a projected steamer, intended to reduce the present record of the six days' voyage across the Atlantic--the _ne plus ultra_ at this time of steam navigation. To secure this present result a continuous steaming for the six days at 20 knot speed is requisite, not to mention an extra day or two at each end of the voyage. The City of Paris and the City of New York, Furst Bismarck, Teutonic and Majestic are capable of this, with the Umbria and Etruria close behind at 18 to 19 knots. Only ten years ago the average passage, reckoned in the same way as from land to land--or Queenstown to Sandy Hook--was seven days with a speed of 17 knots, the performance of such vessels as the Arizona and Alaska. Twenty years ago the length of the voyage was estimated as seven and a half to eight days at a speed of 16 knots, the performance of such vessels as the Germanic and Britannic of the White Star fleet of 5,000 tons and 5,000 horse power. Thirty years ago the paddle steamer was not yet driven off the ocean, and we find the Scotia crossing in between eight and nine days, at a speed of 13 or 14 knots. In 1858 ten and a half to twelve and a half days was allowed for the passage between Liverpool and New York. So as we recede we finally arrive at the pioneer vessels, the Sirius and Great Western, crossing in fourteen to eighteen days at a speed of 6 to 8 knots. For these historical details an interesting paper may be consulted, "De Toenemende Grootte der Zee-Stoombooten," 1888, by Professor A. Huet, of the Delft Polytechnic School. Each of the last two or three decades has thus succeeded, always, however, with increasing difficulty, in knocking off a day from the duration of the voyage. But although the present six-day 20 knot boats are of extreme size and power, and date only from the last two or three years, still the world of travelers declares itself unsatisfied. Already we hear that another day must be struck off, and that five-day steamers have become a necessity of modern requirements, keeping up a continuous ocean speed of 231/2 knots to 24 knots. Shipbuilders and engineers are ashamed to mention the word _impossible_; and designers are already at work, as we saw in the Naval Exhibition, but only so far in the model stage; as the absence of any of the well known distinguishing blazons of the foremost lines was sufficient to show that no order had been placed for the construction of a real vessel. It will take a very short time to examine the task of the naval architect required to secure these onerous and magnificent conditions, five days' continuous ocean steaming at a speed of 24 knots.