the approach of a tropical hurricane, or one of the extremely severe and dangerous storms which occasionally move across the Great Lakes and Atlantic coast.

These warnings are displayed at all stations on the Atlantic and. Gulf coasts of the United States and at the following points about the Caribbean Sea :

The following are the storm warning display stations within the limits covered by this volume, "(n)" indicating that night signals are also displayed:

Weather forecasts are communicated to but no display made at Houston, Tex., and South Boca Grande and Clearwater, Fla. Storm warnings for the Lake Okeechobee district are similarly communicated to Belle Glade, Clewiston, and Sherman, Fla.

Officers of the United States Weather Bureau are maintained at Key West, Tampa, Pensacola, Mobile, New Orleans, Port Arthur, Galveston, Corpus Christi, and Brownsville. Any available information regarding weather conditions can be secured at these offices and barometer comparisons can be made with standards.

(1) WEST INDIA HURRICANES

WEST INDIA HURRICANES

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Tropical cyclones of the North Atlantic Ocean are usually designated as West India hurricanes, but actually many of these storms originate and die out far from the mainland and hundreds of miles from the West Indies. The storm area varies from about 100 miles to 500 or more miles in width, with a comparatively calm center some 10 or 20 miles in diameter. This center is an area of lowest atmospheric pressure around which the wind blows in a more or less circular course (spirally) in a direction contrary to the hands of a watch. In some respects the center, or "eye" is the most dangerous part of the hurricane and is therefore a region especially to be avoided; for although the air movement within it, if any, is usually light and fitful, the seas in this area in most cases are very heavy and confused, rendered so by the shifting violent winds surrounding it. The storm field advances in a straight or curved track, sometimes with considerable speed, at other times at a very slow rate. The highest rates of progression usually occur when the storm moves northward or northeastward over the United States, or in middle or higher latitudes over the ocean. The average speed is about 12 or 15 miles an hour.

Hurricanes form over a wide range of the ocean between the Cape Verde and the Windward Islands, over the western part of the Caribbean Sea, and in the Gulf of Mexico. While some move northward in the beginning, especially those that originate southeast of Bermuda, the majority take a westerly to northwesterly course. Of these some curve gradually northward, either to the eastward of or above the larger islands of the West Indies, then turn northeasterly or easterly near to or at considerable distance from the Atlantic coast of the United States. Others pass over or south of the greater islands and enter the Gulf of Mexico; thence curve northward or northeastward and strike some part of the east Gulf coast or continue to the westward and strike the west Gulf coast. Tracks of hurricanes are shown on the pilot charts of the North Atlantic Ocean and Central American waters, published monthly by the United States Hydrographic Office.

The hurricane season is likely to begin in June and close with November. The months of greatest frequency are August, September, and October. Hurricanes are most likely to be severe during August and the early half of September. During all the months of the season, however, the possibilities of encountering an intense storm are sufficiently great to warrant the mariner in keeping careful watch of the weather elements while in these waters.

Signs of approach.-One of the earliest signs of a hurricane is the appearance of high cirrus clouds which converge toward a point on the horizon that indicates the direction of the center of the storm. The snow-white fibrous mares' tails appear when the center is about 300 or 400 miles distant. Another usual early indication is a long, heavy swell propagated to a considerable distance, sometimes 2 or 3 days in advance, when there is no intervening land to interrupt it. This swell comes from the general direction in which the storm is approaching. There is usually a slight rise of the barometer at the outset, followed by a continuous fall. In front of the storm, if it is advancing in some westerly direction toward the observer,

the winds blow from a northerly point (northeast, north, or northwest); if in some northerly direction toward the observer, they will blow from an easterly point (southeast, east, or northeast). A further indication is a rough, increasing sea. If one or more of these signs be wanting, there is little cause for anticipating a hurri

cane.

As the storm center approaches the barometer continues to fall; the velocity of the wind increases and blows in heavy squalls, and the changes in its direction become more rapid. Rain in showers accompanies the squalls, and when closer to the center the rain is continuous and attended by furious gusts of wind; the air is frequently thick with rain and spume drift, making objects invisible at a short distance. A vessel on a line of the hurricane's advance will experience the above disturbances, except that as the center approaches the wind will remain from the same direction, or nearly so, until the vessel is close to or in the center.

Distance from center.-The distance from the center of a hurricane can only be estimated from a consideration of the height of the barometer and the rapidity of its fall, and the velocity of the wind and rapidity of its change in direction. If the barometer falls slowly and the wind increases gradually it may be reasonably supposed that the center is distant; with a rapidly falling barometer and increasing winds the center may be supposed to be approaching dangerously near.

Practical rules. When there are indications of a hurricane, vessels should remain in port or seek one if possible, carefully observing and recording the changes in barometer and wind and taking every precaution to avert damage by striking light spars, strengthening moorings, and, if a steamer, preparing steam to assist the moorings. In the ports of the Southern States hurricanes are generally accompanied by very high tides, and vessels may be endangered by overriding the wharf where moored if the position is at all exposed.

Vessels in the Straits of Florida may not have the sea room to maneuver so as to avoid the storm track and should use every endeavor to make a harbor or stand out of the straits to obtain sea room. Vessels unable to reach port and having sea room to maneuver should observe the following rules:

When there are indications of the near approach of a hurricane, sailing vessels should heave to on the starboard tack and steamers remain stationary and carefully observe and record the changes in wind and barometer so as to find the bearing of the center and ascertain by the shift of wind in which semicircle the vessel is situated. The safety of the vessel often depends on heaving to in time.

Bearings of center.-Facing the wind, the storm center will be 8 to 12 points to the right; when the storm is distant it will be from 10 to 12 points, and when the barometer has fallen five- or six-tenths it will be about 8 points.

A line drawn through the center of a hurricane in the direction in which it is moving is called the axis or line of progression, and facing in the direction of its path the semicircle on either side of the axis is called, respectively, the right-hand or dangerous semicircle and the left-hand or navigable semicircle.

(1) TIDES AND CURRENTS

To find in which semicircle the vessel is situated:

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If the wind shifts to the right, the vessel will be in the right-hand or dangerous semicircle with regard to the direction in which the storm is traveling, in which case the vessel should be kept on the starboard tack and increase her distance from the center.

If the wind shifts to the left, the vessel will be in the left or navigable semicircle. The helm should be put up and the vessel run with the wind on the starboard quarter, preserving the compass course, if possible, until the barometer rises, when the vessel may be hove to on the port tack, or if there is not sea room to run, the vessel can be put on the port tack at once.

Should the wind remain steady and the barometer continue to fall, the vessel is in the path of the storm and should run with the wind on the starboard quarter into the navigable semicircle.

In all cases act so as to increase as soon as possible the distance from the center, bearing in mind that the whole storm field is advancing.

In receding from the center of a hurricane the barometer will rise and the wind and sea subside.

TIDES AND CURRENTS

Tide Tables for the Atlantic Ocean are published in advance annually by the United States Coast and Geodetic Survey, price 25 cents. This volume supplies full tidal data for the east coast of North and South America, the west and north coasts of Africa, and all of Europe.

It contains a table of full daily predictions of the times and heights of high and low waters for certain reference stations along the coasts, with full explanations for the use of this table. The use of Table 2 of the Tide Tables should be known to every navigator. By means of this table the predictions given for the reference ports are extended so as to enable one to obtain the predictions for each day for a large number of other stations.

The effect of strong winds, in combination with the regular tidal action, may at times cause the water to fall below the plane of reference of the chart, mean low water. The water may also rise about the same amount above mean high water due to similar causes. Northers, occurring along the Gulf Coast from November to April, may lower the water from 4 to 5 feet.

Caution. In using the Tide Tables, slack water should not be confounded with high or low water. For ocean stations there is usually but little difference between the time of high or low water and the beginning of ebb or flood current; but for places in narrow channels, land-locked harbors, or on tidal rivers, the time of slack current may differ by 2 or 3 hours from the time of high- or low-water stand, and local knowledge is required to enable one to make the proper allowances for this delay in the condition of tidal currents. To obtain the times of slack water, reference should be made either to figures given for various places in this volume of the Coast Pilot or to the Current Tables.

Current Tables for the Atlantic Coast of the United States are published in advance annually by the United States Coast and Geodetic

Survey. This volume, which sells for 10 cents per copy, includes the daily predicted times of slack water and the times and velocities of strength of flood and ebb for certain reference stations and a table of current differences and constants by means of which corresponding daily predictions may be readily obtained for numerous other places. These tables also include current diagrams for six bodies of water along the coast, which show in a graphical form the velocities of the flood and ebb currents and the times of slack and strength over a considerable stretch of the channel of these waterways.

Tides, Gulf of Mexico.-In the Gulf of Mexico the periodic tides are usually small and may, therefore, be greatly modified and sometimes entirely obliterated by fluctuations in the water surface due to the winds or other meteorological conditions.

At Key West the mean rise of the tide is less than 12 feet, with high water occurring about 10 hours after the moon's meridian passage. Extreme variations in the level from 112 feet below the plane of reference to 3 feet above may occur in this locality.

Along the western coast of the peninsula of Florida from Cape Sable to Apalachee Bay, the mean rise of the tide varies from 2 to 3 feet, with high water from 3 to 4 hours later than at Key West. Extreme tides from 3 feet below to 6 feet above the plane of reference have been observed on this coast.

Along the northern shore of the Gulf of Mexico from St. George Sound to the Rio Grande the tide is very irregular and generally diurnal that is, during a large part of each month only one high and one low water will occur each day, especially near the time of the greatest north and south declination of the moon. When the moon is near the Equator two high and two low waters each day will generally occur, but the range of tide will be smaller at this time.

The mean rise of the tide along this shore is less than 2 feet, but fluctuations due to the wind from 32 feet below to 4 feet above the plane of reference are not uncommon. During the severe storms that occasionally visit this region, high waters from 10 to 15 feet above the plane of reference have been reported at Galveston, Tex.

The periodic or astronomical tide, small at the mouth of the Mississippi River, gradually diminishes as it ascends the river until it finally becomes completely masked by the larger fluctuations resulting from meteorological conditions. At New Orleans the astronomical tide is so small as to be of no practical importance, although on some days during a month periodic fluctuations amounting to several tenths of a foot have been noted. There is, however, a large fluctuation in the level due to the condition of the river. The mean

annual fluctuation at New Orleans is about 14 feet, the water being highest in the spring months and lowest during the autumn and early part of the winter. An extreme fluctuation of 21 feet in the river level at this city has been reported.

For more detailed information concerning the tides in the Gulf of Mexico, the Tide Tables for the Atlantic Ocean should be consulted. Currents, Gulf of Mexico.-Under normal conditions, and at all seasons of the year, the waters passing northward through Yucatan Channel into the Gulf of Mexico spread out in various directionswesterly, northerly, and easterly. Taking the Gulf as a whole, the