For foreign service, or for those parts of the world where the necessary supplies of fuel for steamers cannot easily be procured, the combining the two principles in a ship may be useful; but wherever perfect steamers can be available, they should decidedly have the preference. But for some time to come, causing both steamers and sailing vessels to act together for mutual assistance and support in action, especially in distant parts of the world, must obviously be desirable. It appears to be demonstrated that a steamer, from fifteen hundred to two thousand tons burden, and upwards, possesses great proportional advantages over one of only four or five hundred, in carrying troops, cargo, or fuel; and her increased power of steam, gives her also proportional superiority in forcing her way through the water, and storms or heavy seas have much less effect upon her than upon smaller vessels. A steamship of war of two thousand tons burden, well manned and armed--and she need not carry many, but they ought to be guns of long range--must possess such powers of movement, and of destruction, as cannot be easily calculated or understood; and conceive that ship to carry, independent of her crew, (which need not be anything like so numerous as that of even a large frigate,) a regiment of cavalry, or two of infantry; then suppose thirty such steam ships conveying an army of perhaps 30,000 men, cavalry, infantry, and artillery, such as I am so anxious to have called out in the manner I have proposed, and which could be carried by these irresistible steamers into almost any port having sufficient depth of water, or to any selected point, and there landed, ready to act against an unprepared, or perhaps distracted people; and how easy it would be with such ships to supply an army afterwards with every requisite; and the object in view being accomplished, or even if frustrated, with what little difficulty could the troops, and their materiel, be again received on board, and conveyed to any other point of attack, or back to our own shores. I had written the above observations, when I saw, by accident, the following description of the Cyclops steam frigate, and from what is said of her, it may be seen what I had in view. A few of the 96-pounders will soon decide the fate of a battle.