The overloading of the Brooklyn bridge is repeated in the subway--that hidden giant of New York, which is the real backbone of the island of Manhattan. Built to carry four hundred thousand humans a day, that busy railroad has begun to carry more than a million each working day. How it is done, no one, not even the engineers of the company that operates it, really knows. The riders in the great tube who have to use it during the busiest of the rush hours are willing to hazard a guess, however. It is probable that in no other railroad of the sort would jamming and crowding of this sort be tolerated for more than a week. Yet the patrons of the subway not only tolerate but, after a fashion, they like it. You can ask a New Yorker about it half an hour after his trip down town, sardine-fashion, and he will only say: "The subway? It's the greatest ever. I can come down from Seventy-second street to Wall street in sixteen minutes, and in the old days it used to take me twenty-six or twenty-seven minutes by the elevated." There is your real New Yorker. He would be perfectly willing to be bound and gagged and shot through a pneumatic tube like a packet of letters, if he thought that he could save twenty minutes between the Battery and the Harlem river. No wonder then that he scorns a relatively greater degree of comfort in elevated trains and surface cars and hurries to the overcrowded subway. But New York astir in the morning is more even than Manhattan, the Bronx and the populous boroughs over on Long island. Upon its westerly edge runs the Hudson river--New Yorkers will always persist in calling it the North river--one of the masterly water highways of the land. The busy East river had been spanned by man twice before any man was bold enough to suggest a continuous railroad across the Hudson. Now there are several--the wonderful double tubes of the Pennsylvania railroad leading from its new terminal in the uptown heart of Manhattan--and two double sets of tunnels of a rapid-transit railroad leading from New Jersey both uptown and downtown in Manhattan. This rapid transit railroad--the Hudson & Manhattan, to use its legal name, although most New Yorkers speak of it as the McAdoo Tubes, because of the man who had the courage to build it--links workaday New York with a group of great railroad terminals that line the eastern rim of New Jersey all the way from Communipaw through Jersey City to Hoboken. And the railroads reach with more than twenty busy arms off across the Jersey marshes to rolling hills and incipient mountains. Upon those hills and mountains live nearly a hundred thousand New Yorkers--men whose business interests are closely bound up in the metropolis of the New World but whose social and home ties are laid in a neighboring state. These--together with their fellows from Westchester county, the southwestern corner of Connecticut and from the Long island suburban towns--measure a railroad journey of