An Italian savant announces that when the fog is so thick as to prevent signals being seen from one station to another, the difficulty may be greatly diminished by placing a colored glass between the eye and the eye-piece of the telescope. The best color for those who have strong eyesight is dark red; while those who are short-sighted find light red preferable. He accounts for the fact by stating that the white color of the fog strikes too powerfully upon the eye, particularly if the glass have a large field; and the intensity of the light is diminished by the interception of a part of the rays by the colored glass, so that the eye is less wearied. _The Velocity of Artificial Light_ has been the subject of some very ingenious experiments by M. Fizean. A point of intense brightness, produced by oxy-hydrogen light, is concentrated by a lens, and being received upon a mirror placed at about two leagues distance, is reflected back again in the same line. This is effected so exactly that scarcely any deviation in the course of the two rays can be perceived, the going and returning ray appearing one within the other. Behind the point of light is placed a wheel having 720 teeth, so adjusted that the light shines between two of the teeth, so that when the wheel is at rest, an eye placed behind it receives the impression of the full ray. When the wheel is moved so that 12·6 revolutions are made in a second, the teeth of the wheel appear continuous, and half the light is obstructed. If the velocity be sufficiently accelerated all the light is cut off, and that rate shows the time necessary for the light to have traversed the two leagues and back again, for the observer sees only the returning ray. The velocity of artificial light has thus been fixed at 70,000 French leagues in a second, which agrees remarkably with that given by astronomers to solar light, 192,500 miles in a second. The English mile, it will be recollected is a trifle longer than the French mile. A paper read before the British Association, describes several remarkable hail storms which have occurred in India. The weight of some masses of ice which have fallen exceeds 14 pounds. Many of these masses, under a rough external coat, contained an interior of clear ice. Immense conglomerated masses of hail stones had been known to be swept down the mountain ravines by the torrents which succeeded the storms; and in one of these conglomerations a snake was found frozen up, and apparently dead; but it revived on being thawed out.