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was proved to demonstration. The Astronomer Royal took a strong view of the case, saying of one instance: "It 'really gave me a feeling of melancholy "to see the results of such exquisite "workmanship entirely annihilated by "subsequent faults in the mounting and "adjustment." The attention of the Trinity Brethren was called to this defect; and, by the zealous co-operation of Professor Faraday and Mr. James Chance, means were devised for readjusting the bands of glass, or for fixing them properly in the first instance. During this investigation several

curious facts were noticed. Thus sailors at Whitby had complained that the lighthouse gallery cut off the lower beams of light; it was not the gallery, but the very prisms of glass which ought to have gathered up that light for the benefit of the sailor. The revolving light at Cape Gris Nez has been praised both in parliament and out of it, and has drawn upon itself the special admiration, not only of those landsmen who may run across by night from Folkestone to Boulogne, but also of the seamen who frequent the whole of the British and French waters. Yet the French authorities thought rather meanly of the light at Gris Nez:-it was an old-fashioned thing, one of the first dioptrics put up, without any of the modern improvements. The commission visited Gris Nez; and, true enough the apparatus was old fashioned. But it was accurately adjusted-probably by Fresnel himself; at any rate by some one who was not content with ordering a beautiful, complicated, and costly piece of mechanism, and getting a mason to set it on top of a tower.

It is not in the above respects alone that great ingenuity has been displayed in lighthouse apparatus. In order to distinguish one light from another, some are made to revolve, while others remain stationary. The rates of revolution also vary. Again, while the majority are white, many are red, and a few green, and some revolving lights are alternately white and red. There are also other varieties. There is a bad variety called the

intermittent, made by bringing a screen before the flame; and there are double lights-for instance, the double revolving light at the Calf of Man, the ludicrously characteristic effect of which I well remember, as it seemed to wink at our passing boat, first with one and then with the other of its fiery eyes. On the night after that fearful day when the Royal Charter was wrecked, I stood on the pier at Honfleur; and, while the vessels were tossing about, the desirableness of good distinctions was deeply impressed on my mind-for there, at the mouth of the Seine, were eleven different lights, most of them having just the same appearance; but among them stood conspicuous and unmistakeable the light of Fatouville, alternately steady white, dull red, red flash, dull red, steady white. There is something peculiarly impressive in the constant change of white, white, red, at regular intervals, in such a lonely situation as the Tuskar or Cape Wrath, when seen on a dark night from the deck of a ship sailing on to the wide Atlantic.

New sources of light. Why should we be confined to the combustion of oil? The Pharos of the future will perhaps be as independent of it as is our present street lamp.

Coal gas. Though the use of gas has been frequently pressed upon the attention of the great lighthouse authorities, they have never adopted it, conceiving it to be dangerous. The municipal bodies, however, have not participated in this dread, and a large proportion of even the most important harbour lights owe their illumination to this source. Some of these are admirably managed and most efficient; but there are others which present a sad contrast-as that at Dover, of which it is reported: "The green light was only distinguishable as the dullest of lights round the "harbour, and by a greenish or blueish hue, not very discernible."

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The same optical apparatus is applicable to a gas as to an oil-flame.

Electric light. All other lights that science has produced appear dim beside the splendour of that small spark which

bursts into view when the conducting wires of a powerful electric current are separated by a minute space, especially if these wires terminate in charcoal points. The worst is, that it is difficult to maintain this spark in a constant state of brilliancy. Many attempts have been made to overcome this difficulty, and many proposals have been submitted for introducing electric lights into lighthouses; but the only one which has been so introduced is that of Professor Holmes. In 1853 he was called to examine some magneto-electric machines that were intended for the decomposition of water, and it occurred to him that they might be made available for producing the charcoal light. He got the light, and set to work to perfect the apparatus. In February, 1857, he first communicated with the Trinity House; and, on December 8, 1858, this brilliant star first beamed forth over the seas from a lighthouse-that at the South Foreland-surprising the sailors, and the inhabitants on the opposite coast of France. The light, as in other cases, is derived from combustion; but it is the combustion of coal in a small steam engine, which rotates a wheel loaded with soft iron cores past another wheel loaded with permanent magnets. This calls into action a force which, carried aloft by stout wires and allowed to pass between the charcoal points of an ingeniouslyconstructed "lamp," produces a light which can only be compared to a fragment of the sun. The experiment

was continued for some months, and was considered successful. But the light was afterwards removed from the South Foreland, the dioptric apparatus of which was ill-adapted for it. Some improvements have since been made; and it is now fitted up with optical apparatus of its own, at Dungeness, and will, probably, be shining again before this paper is printed. It is intended that it shall be permanent. Professor Faraday, who first discovered magneto-electricity, and who is the scientific adviser of the Trinity House, has naturally taken a great interest in the development of this child of his, and in seeing it take a part in the active business of the world.

Lime light. Captain Drummond attempted to introduce into lighthouses the brilliant light produced by the incandescence of a piece of lime in an oxy-hydrogen flame; but, at that time, the difficulty from the cracking of the lime could not be sufficiently overcome. Mechanical genius, however, has done much to remove this, and for three months during the past autumn a light of this character was exhibited, as an experiment, at the South Foreland.

Should either this light or that from the magneto-electric machine eventually come into general use, England will have the honour of initiating an improvement in lighthouse illumination. equal, if not superior, to that effected in France by the genius of Fresnel. Long may there be such a rivalry between the two nations!