The barometer is a faithful guide in the zone of the Trade Winds. Its ordinary variations are so small that any deviation from its normal height requires attention. Its fluctuations are larger beyond the Tropics; but the indications are scarcely less certain if used in conjunction with the thermometer and hygrometer,—hence, more watchfulness is required on the part of the navigator; and it is of the utmost importance to have such a knowledge of the Law of Storms, of storm instruments, and of the signs of the weather, as to be able to detect the presence of a hurricane or cyclone, when as yet sky and sea betoken but little of that blind fury, during the height of which it is so difficult to guide the vessel in safety. One great advantage of such knowledge is a quick apprehension of the indications which forewarn, to make all snug in time. The meteorological signs indicating the approach of a hurricane or cyclone, have been collected from various sources by Mr. Birt, and are enumerated and classed according as the phenomena may be presented to the external sensations of feeling, sight, or hearing. METEOROLOGICAL SIGNS RECOGNIZED BY THE FEELINGS. 1. A sultry, oppressive state of the atmosphere. 2. A calm. METEOROLOGICAL SIGNS RECOGNIZED BY THE EYE. 1. A remarkably clear state of the atmosphere, so that the stars may be seen to rise and set with nearly the same distinctness as the sun and moon. 2. A peculiar white appearance in the zenith, more or less of a circular form. 3. A remarkably red or fiery appearance of the sky. This is not unfrequently of such intensity as to tinge all the surrounding objects with a deep crimson; and when this is seen there can be no question that the violent portion of the cyclone is not far from the vessel. When this red light is seen at night, the impression on the seaman’s mind is that day has broken before its time. 4. A peculiar coloring of the clouds, more especially of an olive green. This is generally the precursor of a most violent and terrific hurricane. 5. A thick, hazy appearance in that quarter of the horizon in which the cyclone is raging. 6. A remarkable and peculiar appearance of the heavenly bodies. When shining through a haze they are said to shine with a pale, sickly light, and are not unfrequently surrounded by rings of light, or halos. Some observers describe the stars “as looking big, with burs about them”; others speak of their “dancing,” and generally they have been noticed as being remarkably bright and twinkling. 7. The sun, on some occasions, has exhibited a blue appearance, and white objects have been seen of a decided light blue color. The sun has also been observed of a pale and somewhat similar appearance to that of the full moon. 8. A dense, heavy bank of cloud in the direction of the hurricane.