234 



'The Scottish Naturalist. 



mencement of the storm, and B its position at the close ; the 

 wind would therefore set in from S.E., veer through S., with heavy 

 rain, and end with S.W. Had the left wing of the gale passed 



w 



over the Bermudas, the direction of the wind would have been 

 northerly. Supposing the diagram to represent a tropical storm 

 of 600 geographical miles in diameter, the dotted line intersect- 

 ing the storm diameter, midway between the storm centre and 

 circumference, would be 493 miles in length ; and as the storm 

 moved onwards to the north at 25 miles an hour, Bermuda would 

 appear to move along that line at that pace. We will now im- 

 agine that the flight of land-birds approached the left wing of the 

 storm from the north, entering it at the same time, and at the 

 same distance from the line separating the two wings at the letter 

 D. While Bermuda appeared to be travelling towards the storm 

 diameter, at 25 miles an hour, the birds would be moving at the 

 more rapid rate of 55 miles an hour in the same direction — that 

 is, allowing them to fly at the moderate speed of 30 miles an 

 hour towards the south, and adding 25 miles for the direct pro- 

 gress of the storm, we arrive at a united speed of 55 miles. It 

 results, therefore, that the birds would reach the storm diameter 



