Thus, everywhere, and in all latitudes, the beacons and wooden towers and huge pyramids of long ago have given place to slender spires of solid masonry, holding powerful signals perhaps hundreds of feet above the waves, and visible as far as the curve of the earth’s surface will permit. Yet in place of the sturdy bonfire of oak, or the huge iron cage full of coals, there is only a single lamp, whose rays are gathered by deep reflectors into a compact bundle of unwasted rays, and doubled and redoubled by rows of magnifying lenses until they can dart to the furthest horizon in a strong beam of steady light. No longer does the mariner trust to his wife to kindle the tar-barrel to guide him home. He knows that nowhere is his government more watchful of its subjects than in its lighthouse service, and that he may trust to having that bright signal to welcome him in the darkness, as well as he can trust his own eyes to see it. The United States alone expends over $2,500,000 annually in looking after her lighthouses, lightships, and buoys. [Illustration: THE LIGHTHOUSE AT ST. AUGUSTINE, FLORIDA.] Indeed, these beacons have become so thickly planted that it has been found necessary to distinguish between them in order to avoid mistaking one for another. At first this was done by doubling, as in the case of New York’s “Highland Lights,” or the twin lights of Thatcher’s Island off Cape Ann, or even trebling them as at Nauset, on Cape Cod, but now the display is made to vary. Thus some of them are simply fixed white lights; some are white and revolve—the whole lantern on the summit of the tower being turned on wheels by machinery, and the flame disappears for a longer or shorter time; while others are white “flash” lights, glancing only for an instant, and then lost for a few seconds, or giving a long wink and then a short one with a space of darkness between. Some lighthouses show a steady red light; others, alternate red and white. By these colors and varying periods of appearance and disappearance (noted on charts, and published by the government in a general seaman’s guide called the “Coast Pilot”), navigators know which light they are looking at when several are in sight. For daylight recognition the towers may be painted half black and half white, or in stripes or bands or spirals, like the big barber’s pole in front of St. Augustine, Florida.