In the central regions of the Atlantic High, the modern sailor, unlike his predecessor in the sailing ship, is delighted by calms or gentle breezes and fair weather. On its northern edge, storms pass from America to Europe, stirring the northern regions of the ocean. On its southern edge, we find the trade winds reaching down into the tropics and turning westward across the West Indies and the Bahamas. A chart of these prevailing winds gives a fairly good indication of the ocean currents. Some of the surface waters are cold, some warm. And where they wander through the tropics as equatorial currents or counter-currents, they are hot and, other things being favorable, we find a birthplace of storms. In some other tropical regions, the waters are cold and no hurricanes form there.
Near the equator, the earth is girdled by a belt of heat, calms, oppressive humidity, and persistent showers. This belt is called the “doldrums.” The trade winds of the Northern Hemisphere reach to its northern edge, while the trades below the equator brush its southern margin. Tropical storms form now and then in and along the doldrum belt at certain seasons—just why, no one knows, for there are hundreds of days when everything seems right for a cyclone but nothing happens except showers and the miserable sultriness of the torrid atmosphere.
Stripped to his waist, the sailor sits on his bunk at night without the slightest exertion while perspiration descends in rivulets from his head and shoulders. Nothing seems capable of making any appreciable change in this monotonous regime. But eight or ten times a year on the Atlantic, in summer or autumn, a storm rears its head in this oppressive atmosphere. Its winds turn against the motions of the hands of a clock, seemingly geared to the edges of the vast, fair-weather whirlwind centered in mid-ocean. Around the southern and western margins of this great whirl the storm moves majestically, gaining in power which it takes in some manner from the heat and humidity—a power which would drain the energies of a thousand atom bombs. The crowning clouds push to enormous heights and deploy ahead of the monster—a foreboding of destruction in its path. Here is one of the great mysteries of the sea. Its heated surface lets loose great quantities of moisture which somehow feed the monster—that we know—but what sets it off is almost as much of a mystery as it was in the time of Columbus.