Our naval architect is not likely at present to proceed further with this monstrous design, exceeding even the Great Eastern in size, if only because no dock is in existence capable of receiving such a ship. He has however learned something of value, namely, that this vessel, if the proper similitude is carried out, is capable of keeping up a speed of 24 knots for five days with ample coal supply, provided the boilers are not found to occupy all the available space. For it is an immediate consequence of Froude's laws that in similar vessels run at corresponding speeds over the same voyage, the coal capacity is proportionately the same, or that a ton of coal will carry the same number of tons of displacement over the same distance. Thus our enlarged City of Paris would require to carry about 4,000 tons of coal, burning 800 tons a day. With the Britannic and Germanic as models of 5,000 tons and 5,000 horse power at 16 knot speed, the 24 knot vessel would require to be of 57,000 tons and 85,000 horse power, to carry sufficient coal for the voyage of 3,000 miles. These enormous vessels being out of the question, the designer must reduce the size. But now the City of Paris will no longer serve as a model, he must look elsewhere for a vessel of high speed, and smaller scale, and naturally he picks out a torpedo boat at the other end of the scale. A speed of 24 knots--and it is claimed even of 25, 26, and 27 knots--has been attained on the mile by a torpedo boat. But such a performance is useless for our mode of comparison, as sufficient fuel at this high speed for ten or twelve hours only at most can be carried--a voyage of, say, 500 miles; while our steamer is required to carry coal for 3,000 miles. The Russian torpedo boat Wiborg, for instance, is designed to carry coal for 1,200 miles at 10 knot speed; but at 20 knots this fuel would last only twenty-seven hours, carrying the vessel 540 miles. It will now be found that with this limited coal capacity the speed of the ordinary torpedo boat must be reduced considerably below 10 knots for it to be able to cross the Atlantic, 3,000 miles under steam. So that, even at a possible speed of 10 knots for the voyage, the full sized 24 knot five-day vessel, of which the best torpedo boat is the model, must have (2.4)^{6}, say 200 times the tonnage, and (2.4)^{7}, or 460 times the horse power. The enlarged Wiborg would thus not differ much from the enlarged City of Paris. A better model to select would be one of the recent dispatch boats, commerce destroyers, or torpedo catchers, recently designed by Mr. W.H. White, for our navy--the Intrepid or Endymion, for instance. The Intrepid is 300 ft. by 44 ft., 3,600 tons, and 9,000 horse power for 20 knot speed, with 800 hours' coal capacity for 8,000 miles at 10 knot speed; which will reduce to 3,000 miles at 16 knots, and 2,000 miles at 20 knots.