Leaving the car at Sixth Avenue, the two men climbed the stairs to the elevated road. They had hardly purchased their tickets when a train drew up at the little station and a minute afterward they were off for Harlem. The horse-car ride, followed by that on the elevated road, started a discussion concerning street-car traffic. The horse car was remembered by the old missionary, who remarked that it came before the steam railroad. Mr. Towne replied, "Yes. But its day is nearly over. New York City does not seem to have fully outgrown this slow street travel, but elsewhere more rapid transit is the rule. New York is coming to it, however. The elevated roads cannot carry all the travel--the horse cars are too slow--the size of the city demands something more than we now have." "What do you expect will be done?" asked Mr. Greenleaf. "We shall have to build a tunnel, an underground railway, a subway. Of course our roads must be either above ground, on the ground level, or below ground. The elevated roads have shown themselves to be unpleasant and annoying. It is not agreeable to look into the upper-story windows of dwellings, nor do people enjoy living on streets where the elevated road runs. Rapid transit is impossible in the street, where cross streets continually delay the cars, and where wagons and carriages of all sorts are regularly passing. The subway is the best method, the only decent way left open." "Would not such a tunnel be dark and damp, dirty and unhealthy in every sense?" asked his uncle. "Oh! no," was the reply. "Boston has recently completed a subway, something like a mile and a half long, with two branches, which has proved its great advantages. Sheltered in winter, cool in summer, never blocked by teams nor interfered with by snow or ice, brilliantly lighted, with air wholesome and dry, and less liable to accidents than any other device yet tested, the Boston Subway is a great success. [Illustration: THE BOSTON SUBWAY.] "Did you say that there was no smoke?" again asked Mr. Greenleaf. "No smoke at all. The cars are run by electricity, and cinders are therefore entirely absent." "Are electric cars coming into general use?" was the next question. "Yes; throughout the country," replied Mr. Towne. "New York even now has its electric roads up town. Horse cars have been replaced by electric cars in almost every city. Cable cars are used in some places, but the electric is preferred. The last few years have seen a wonderful development in electricity in every way, but in no respect greater than in the increase of electric railways. For shorter lines they are competing with the steam cars, and seem to be winning the day. Some steam roads are equipping their lines for electric service, and report successful results so far as tried. Whether the electric car will wholly replace the steam car, time only will tell."