Signalling At Sea.—Mr. John Cran, of the firm of Messrs. Cran & Co., Albert Engine Works, Leith, has just patented a new invention, in the shape of a steam whistle, which is likely to prove of incalculable benefit to navigators in foggy weather. The importance of the introduction of a system of effective signalling, in thick weather, will at once commend itself to seafaring men, and those acquainted with the dangers accompanying the navigation of a ship in a fog. Of course, attempts have been made, more or less successfully, to secure a recognised mode of signalling by a series of successive blows from a whistle; but, with the exception of two methods invented by Messrs. Smith, of Nottingham, these call for only passing notice, as unsuitable to effectively fulfil the purposes for which they were intended. The invention of Mr. Cran. however, is admirably adapted to suit the requirements of a fog signal. It may be briefly described as an organ whistle with a piston in the tube, moved up and down at the will of the operator, and so arranged that with one hand on the lever all the notes through an octave and a half, or even two octaves, maybe consecutively sounded with perfect clearness, from high to low, low to high, or in any order, or long or short. It is completely under control. It will thus be seen that here is an instrument far ahead of the old “one note,” and capable with a code, such as Sir Wm. Thomson’s adaptation of the Morse or other method, if only made general, whereby vessels may at all times, by day, night, or in foggy weather, intimate to each other, not only their courses, but any other information they desire with the greatest facility. For instance, how many accidents and misadventures might be avoided, if only the one vessel knew what the other vessel was doing, or intended to do. Again, in the Boyal Navy, the admiral of a fleet might employ it in giving orders to the vessels under his command, and its musical compass would suit it for making bugle calls. On our railways, too, one would think there is a field for this whistle. It is undoubtedly a step in the right direction, and if its extended application lessens the chances of collision, and increases the security of travelling by sea and land, the whistle will become a public benefactor.