THE EUROPEAN STORM OF DECEMBER 21-2S, 1S3C. 25 



the winter storms of the United States, the north and south diameter is generally 

 very much greater than the east and west diameter. 



2. When storms are circular in form, the area of rain or snow is sometimes 

 1,500 miles in diameter; when their form is elliptical, the area of rain or snow is 

 sometimes 1,000 miles wide, and 2,000 or 3,000 miles long. 



3. Violent storms sometimes remain sensibly stationary for four or five days; 

 but generally the centre of a storm has a progressive movement along the earth's 

 surface. The rate of this progress has been observed to vary from zero to 44 miles 

 per hour. From our limited number of observations, it seems probable that Ame- 

 rican storms travel more rapidly than European storms. 



4. Within the limits of prevalent westerly winds, when violent storms advance 

 with considerable rapidity, the direction of progress is always from west to east. 

 This direction is not absolutely uniform, but has been observed to vary from about 

 due east to N. 54° E. 



5. Great storms of rain and snow are accompanied by a depression of the baro- 

 meter near the centre of the storm, and a rise of the barometer near the margin ; 

 but this rise is not generally uniform along the entire margin. 



6. The depression of the barometer at the centre of a storm sometimes amounts 

 to more than an inch below the mean height; and the rise along some portion of 

 the margin sometimes amounts to more than an inch above the mean height. 



7. Winter storms commence gradually, and generally attain their greatest violence 

 only after a lapse of several days ; after a time their violence gradually diminishes, 

 and at length they disappear entirely. This succession of changes requires a period 

 of several days, sometimes one or two weeks, and possibly even longer. Sometimes 

 all these changes are experienced over the same country; that is, the storm makes 

 no progress from place to place. More commonly, however, the storm travels along 

 the earth's surface ; and although the same storm may continue for one or two 

 weeks, or even longer, its duration at any one place may not exceed one or two 

 days. 



8. For several hundred miles on each side of the centre of a violent storm, the 

 wind inclines inwards towards the area of least pressure, and at the same time 

 circulates around the centre in a direction contrary to the motion of the hands of a 



watch. 



9. In Europe, as well as in the United States, on the north side of a great storm 

 the prevalent winds are from the northeast, while on the south side they arc from 

 the southwest. 



10. The force of tlie wind is proportional to the magnitude and suddenness of 

 the depression of tlio barometer ; but very near the centre of a violent storm there 

 is often a calm. 



11. On the borders of the storm, near the line of maximum pressure, the wind 

 has but little force, and tends outwards from the line of greatest pressure. 



12. The wind uniformly tends from an area of high barometer towards an area 

 of low barometer; and this is probably the imost important law regulating the 

 movement of the wind. 



13. In a crreat storm, the centre of the area of high thermometer frequently does 



