HURRICANES IN THE BAY OP NORTH AMERICA. 187 
chronous data charted on a daily weather map. This sub¬ 
ject is so well understood at places like Manilla, Mauritius, 
and Havana, that a hurricane cannot come within 500 miles 
without detection by means of observations of the upper 
clouds, together with various other well-known indications, 
such as peculiar atmospheric effects, increased ocean swell, 
etc., although its existence might not even be suspected by 
the uninitiated. Indeed, a good example is furnished in 
the present case, where the motions of the storm were clearly 
traced from Havana when it was central about 900 miles 
away. 
One very important source of information regarding a 
storm off the coast, generally recognized by meteorologic 
offices and published on their daily weather maps, in Eng¬ 
land and France, for instance, is the state of the sea. A long 
rolling swell from the direction of a distant storm is one of 
the earliest signs of its approach, and perhaps the very best 
index of its severity. This valuable source of information 
might well be utilized along our own coast. It will be re¬ 
membered that it was a marked feature of the recent hurri¬ 
cane, and the enormous seas started by the great whirlwind 
had overspread almost the entire western half of the Atlantic 
as early as the 5th, when it was central 750 miles S SE. 
from Hatteras. At this time there was a heavy northeast¬ 
erly swell at Jamaica and through the Windward Channel ; 
northeasterly and easterly, all along the Bahama Islands and 
northern Florida; very heavy surf at Bermuda; long, roll¬ 
ing swell from S SE. off Hatteras, perceptible as early as 
the 2d and increasing daily; long, low southerly swell off 
Nantucket, perceptible as early as the 4th, when the storm 
center was 1,300 miles away, and increasing daily. The 
more severe the storm, the more important is this source of 
information. The energy of a hurricane is so concentrated 
that by the time its presence is indicated on a daily weather 
map by the increased velocity of the wind and low reading 
of the barometer the warning is too late to be of much value. 
The high tides and floods along the coast between Hatteras 
