258 PHILOSOPHY OF STORMS. 



at the several points over which it passed, may be stated at 

 from seven to twelve hours. 



"The general width of the tract, influenced, in a greater 

 or less degree, by the gale on the American coast, is esti- 

 mated to have been from five to six hundred miles. 



" Width of the hurricane portion of the tract, or severe 

 part of the gale, 150 to 250 miles. 



" Semi-diameter of the hurricane portion of the storm, 75 

 to 125 miles. 



" Rate of the storm's progress from the Island of St. 

 Thomas to Providence Island, Bahamas, 15 nautical miles 

 per hour. 



" Rate of progress from Providence to St. John's, Florida, 

 16 miles per hour. 



" From St. John's to Cape Hatteras, N. C., 16| miles per 

 hour. 



" From Cape Hatteras to Nantucket, on the south eastern 

 coast of Massachusetts, 18 miles per hour. 



" From Nantucket to Sable Island, off the south eastern 

 coast of Nova Scotia, 20 miles per hour." 



Extract of a letter from the Master of the Ship Illinois, 

 I sailed from New Orleans on the 3d of August, bound to 

 Liverpool. Nothing worth notice occurred until the 15th 

 of August, in lat 33 N., Ion. 77 10', when there was a 

 very heavy swell from the S., more than ever I had expe- 

 rienced before in this part, unless preceded by heavy gales. 

 We had no indication of wind at this time, but there was 

 a dull arid heavy appearance in the S. During the day, the 

 wind was light and at the S. E. ; at night, it shifted to S. S. W. 

 On the 16th, it was a fresh and wholesome breeze; so that 

 with the help of the Gulf stream we ran at a great rate, 

 steering N. E., and at noon we were in lat. 36, Ion. 73. 

 On the 17th, the wind continued steady at S. S. W., blow- 

 ing a strong and wholesome breeze, but the appearance to 

 the S. continued dull and heavy; the sea was smooth again, 



