New York is built upon an island, which is I believe about ten miles long, counting from the southern point at the Battery up to Carmansville, to which place the city is presumed to extend northwards. This island is called Manhattan,--a name which I have always thought would have been more graceful for the city than that of New York. It is formed by the Sound or East river, which divides the continent from Long Island, by the Hudson river which runs into the Sound or rather joins it at the city foot, and by a small stream called the Haarlem river which runs out of the Hudson and meanders away into the Sound at the north of the city, thus cutting the city off from the main land. The breadth of the island does not much exceed two miles, and therefore the city is long, and not capable of extension in point of breadth. In its old days it clustered itself round about the Point, and stretched itself up from there along the quays of the two waters. The streets down in this part of the town are devious enough, twisting themselves about with delightful irregularity; but as the city grew there came the taste for parallelograms, and the upper streets are rectangular and numbered. Broadway, the street of New York with which the world is generally best acquainted, begins at the southern point of the town and goes northward through it. For some two miles and a half it walks away in a straight line, and then it turns to the left towards the Hudson, and becomes in fact a continuation of another street called the Bowery, which comes up in a devious course from the south-east extremity of the island. From that time Broadway never again takes a straight course, but crosses the various Avenues in an oblique direction till it becomes the Bloomingdale road, and under that name takes itself out of town. There are eleven so-called Avenues, which descend in absolutely straight lines from the northern, and at present unsettled, extremity of the new town, making their way southward till they lose themselves among the old streets. These are called First Avenue, Second Avenue, and so on. The town had already progressed two miles up northwards from the Battery before it had caught the parallelogrammic fever from Philadelphia, for at about that distance we find "First Street." First Street runs across the Avenues from water to water, and then Second Street. I will not name them all, seeing that they go up to 154th Street! They do so at least on the map, and I believe on the lamp-posts. But the houses are not yet built in order beyond 50th or 60th Street. The other hundred streets, each of two miles long, with the Avenues which are mostly unoccupied for four or five miles, is the ground over which the young New Yorkers are to spread themselves. I do not in the least doubt that they will occupy it all, and that 154th Street will find itself too narrow a boundary for the population.