On arriving at the approach to the entrance or mouth of the river Hudson, which is formed by an arm of the estuary, we turned the promontory, leaving Jersey on the left, the battery as we entered the harbour being in the foreground. The guns-bristled from this fortress with menacing aspect, and the sentinels, in light blue uniforms and Kosciusko caps, silently paced the ramparts with automatic regularity. This fortification, though formidable in appearance, and certainly in a commanding position, I was subsequently informed is little more than a mimic fort; this arises from the want of attention paid to defences of the kind in America, the little existing chance of invasion, perhaps, causing the indifference to the subject. If, however, the spirit of aggressive conquest shown by the federal government, of late years, of which the invasion of Mexico is a fair specimen, should continue to develop itself, it is not difficult to foresee that it will be necessary policy to pay greater attention to the subject, and to keep in a more effective state the seaboard defences of the country, as well as their army, which is at present miserably deficient. This has heretofore been so far neglected, as regards the marine, that not long before I arrived the commander of a French ship of war was much chagrined, on firing a salute as he passed the battery at New York, to find that his courtesy was not returned in the customary way. He complained of the omission as either a mark of disrespect to himself, or an insult to his nation, when it came out in explanation that the garrison was in such a defective state that there were not the appliances at hand to observe this national etiquette. The city of New York is built almost close to the water's edge, with a broad levee or wharf running round a great portion of it. Its general appearance gives to a stranger an impression of its extent and importance. It has been aptly and accurately described as a dense pack of buildings, comprising every imaginable variety, and of all known orders of modernized architecture. The tide flows close up to the wharves which run outside of the city, and differs so little in height at ebb or flow, that vessels of the largest class ride, I believe, at all times as safely as in the West India docks in London, or the imperial docks of Liverpool. Here was assembled an incalculable number of vessels of all sizes and all nations, forming a beautiful and picturesque view of commercial enterprise and grandeur, perhaps outvying every other port in the world, not excepting Liverpool itself.