Experiment has proved it safer than mineral oil, and it is cheaper than gas, which however is occasionally used near a city whence it can easily be obtained. Only in some few special instances electric light, the most intense procurable, is employed. [Illustration: LIGHT-HOUSE ON MT. DESERT, COAST OF MAINE.] The Centennial birth-day gift of the citizens of France to the American Republic is a colossal brazen statue of Liberty, which is to be a Pharos to light the shipping of the world into New York harbor. It will stand on Bedloe's Island, and from the torch in its uplifted hand will flash a calcium light. Only the hand and arm were finished in time to be sent to the Exposition; but these were on so gigantic a scale that a man standing in the little gallery which ringed the thumb holding the torch seemed like an ant or a fly creeping along at that height. Sir Walter Scott--dear Sir Walter, whose "Tales of a Grandfather" and Scottish stories and poems were so delightfully familiar to the boys and girls of the last generation, left a charming little diary of a voyage he made in the summer of 1814, on board a Light-house yacht, in company with the Commissioners of Northern Lights,--who have charge of the Light-houses in Scotland, as the Elder Brethren of Trinity House have of those in England,--their Surveyor-Viceroy, the engineer Stevenson, and a few other gentlemen. The first Light-house they visited was an old tower, like a "border keep," still illuminated by a grate fire on top. The commissioners think of substituting an oil revolving-light; but Sir Walter wonders if the _grate_ couldn't be made to revolve! Next they came to Bell Rock, which, in olden times, was the terror of sailors feeling their way in and out of the islands and rocks and shoals of the beautiful, perilous coast of Scotland. Inch-cape Rock, as it was then called, had shipwrecked many a helpless crew before the Abbot of Aberbrathock, fifteen miles off, out of pity caused a float to be fixed on the rock, with a bell attached which, swinging by the motion of the waves, warned seamen of the danger. Many years later, when Abbot and Monastery bells had all become things of the past, a humane naval officer set up two beacons on Bell Rock by subscription; but they were soon destroyed by the fury of the elements. At last in 1802, people began to realize the danger of this terrible reef in the highway of navigation, and the Commissioners appointed Mr. Robert Stevenson to erect a Light-house on this point. It was a perilous undertaking, and once the engineer and his workmen made a very narrow escape from drowning; but it was successfully accomplished by the brave and skilful Stevenson. Sir Walter thus describes this famous beacon.