Less picturesque than lighthouses and lightships, and with far less of human interest about them, are the buoys of various sorts of which the Lighthouse Board has more than one thousand in place, and under constant supervision. Yet, among the sailor's safeguards, they rank near the head. They point out for him the tortuous pathway into different harbors; with clanging bell or dismal whistle, they warn him away from menacing shallows and sunken wrecks. The resources of science and inventive genius have been drawn upon to devise ways for making them more effective. At night they shine with electric lights fed from a submarine cable, or with steady gas drawn from a reservoir that needs refilling only three or four times a year. If sound is to be trusted rather than light, recourse is had to a bell-buoy which tolls mournfully as the waves toss it about above the danger spot, or to a whistling buoy which toots unceasingly a locomotive whistle, with air compressed by the action of the waves. The whistling buoy is the giant of his family, for the necessity for providing a heavy charge of compressed air compels the attachment to the buoy of a tube thirty-two feet or more deep, which reaches straight down into the water. The sea rising and falling in this, as the buoy tosses on the waves, acts as a sort of piston, driving out the air through the whistle, as the water rises, admitting more air as it falls. Serving a purpose akin to the lighthouses, are the post and range-lights on the great rivers of the West. Very humble devices, these, in many instances, but of prodigious importance to traffic on the interior waterways. A lens lantern, hanging from the arm of a post eight or ten feet high, and kept lighted by some neighboring farmer at a cost of $160 a year, lacks the romantic quality of a lighthouse towering above a hungry sea, but it is because there are nearly two thousand such lights on our shallow and crooked rivers that we have an interior shipping doing a carrying trade of millions a year, and giving employment to thousands of men.