An invention of considerable importance in connection with the probability of saving life at sea has made its appearance during the month. This consists of an adaptation of the use of oil at sea to the ordinary life-buoy. Round the inside of the buoy is a brass reservoir filled with oil. This is so arranged that when the buoy is hung upon the vessel’s side no oil can escape; while the moment it assumes a horizontal position, as, for instance, when it is thrown into the sea, the oil flows freely, and the water all around the buoy is rapidly covered with a thin film. This soon widens into a large circle, within which, of course, the waves are unbroken, which enables persons to be the more easily secured by the ship’s boats. Since it is a well-known fact that in rough weather, when the cry ‘Man overboard!’ is oftenest heard, life-buoys are frequently useless, as even the strongest men are commonly washed off them, this practical adaptation of the use of oil at sea will probably prove of signal importance. It could, we imagine, also be readily applied to many of those improvised sea-rafts and similar appliances, and render them of great value in rough weather. It was the fault of many of those ingenious contrivances of this kind which were to be seen at the Fisheries Exhibition last year, that no one could possibly live on them in broken water, and this objection the use of oil in this way would certainly obviate. It should be noticed, however, that the chief value of the invention consists in the arrangement for the oil to flow automatically. In addition to the electrically lighted colliery in South Wales, noticed in last ‘Month,’ we hear of another in Lanarkshire belonging to Mr John Watson, Earnock, near Hamilton. There may possibly be other workings thus illuminated throughout this country; and there is no doubt that ere long the brilliant and comparatively safe electric light will be generally adopted underground.