Planted in the midst of the inland crowded streets to which New Yorkers were ever drawn, Central Park was the stroke of genius needed to complete the grid, by offering a counterpoint of manmade Nature: the largest and greenest of rectangles, superimposed on the checkerboard, immeasurably boosting land values; it drew like a magnet to its edges the most pres txgious mansions and apartment buildings. "With the implantation of Central Park," wrote the historian Richard Plunz, "the morphology of modern Manhattan was firmly established: that of a luxurious center and of a marginal periphery in terms of residential real estate, and quite the opposite in terms of commercial and industrial property. In the Manhattan psyche, Central Park became the 'waterfront': a kind of 'green' sea. Bourgeois aspirations placed Manhattan in a park, rather than in the sea. Water was its lifeblood, but not its soul.") To return to our chronological summary: the opening of the Erie Canal in 1825 secured the triumph of New York as a great port, by connecting the Atlantic seaport with the interior, all the way to Lake Erie. While the Erie Canal undoubtedly magnified the port's commercial importance, by bringing flour, wheat, lumber and other commodities from the frontier to the city, and transporting to the hinterlands those niceties of civilization Westerners wanted, other factors besides the canal, argued Robert Greenhalgh Albion in his classic study, The Rise of New York Port (18151860), may have contributed as significantly to the port's ascendance. First, there was the innovation of regularly scheduled ocean liners, such as the Black Ball Line, which contracted to leave at a certain date from New York and arrive at Liverpool on schedule, instead of dawdling from port to port, picking up a full complement of cargo. (Already the city was turning its temperamental impatience, the "New York minute," to commercial advantage.) Improvements in boat design made for faster ships, such as the famous China clippers. The East River Yards of Manhattan became a major center of quality shipbuilding. The city's banking institutions tied the hinterlands to New York as firmly as had the Erie Canal. Finally, the fact that the steamship was financed and perfected in New York gave the region a head start in that mode of traffic. By i860 the port of New York was handling 52 percent of the nation's combined imports and exports. The New York Custom House was the principal source of revenue of the federal government. An army of customs inspectors, including Herman Melville, collected duties there that, accord lng to Albion, "were enough to pay the whole running expenses of the national Government, except the interest on the debt." Part of this lucrative trade involved the Cotton Triangle, by which southerngrown cotton (in the first half of the nineteenth century, America's most important export) passed through New York on its way to England and France.