§ 807. STORMS, HURRICANES, AND TYrilOONS. 431 



would scarcely be two miles, and its thickness would not be as 

 great, in proportion to its diameter, as half the thickness of this 

 leaf is to the length of an inch. Now the difference in rate of the 

 diurnal rotation between the northern and southern limbs of the 

 disc would be sufficient, irrespective of any other power, to break 

 it up. Suppose its southern limb to be in 20° N., its northern limb 

 would be 1000 miles, say 17°, farther north, that is, in 37°. Diur- 

 nal rotation would carry to the east the air in the southern limb 

 at the rate of 845 miles an hour ; but when this same air comes 

 round on the northern limb, diurnal rotation would carry it east- 

 ward at the rate only of 720 miles. Because the wind hauls in a 

 particular way, it does not, as by diagram (§ 799) it has been 

 shown, follow that it is blowing in a circle, or that the centre 

 of the storm is at ri2;ht ano;les to its line of direction. 



807. In the extra-tropical regions of each hemisphere furious 

 Extra-tropical gales, galcs of wlud also occur. Ouc of thesc, remarkable 

 for its violent effects, was encountered on the 24th of December, 

 1858, about three hundred miles from Sandy Hook, latitude 89° 

 north, longitude 70° west, by the " San Francisco," steam-ship. 

 That ship was made a complete wreck in a few moments, and she 

 was abandoned by the survivors, after incredible hardships, exer^ 

 tions, and sufferings. Some months after this disaster I received 

 by the California mail the abstract log of the fine clipper ship 

 " Eagle "Wing" (Ebenezer H. Linnell), from Boston to San Fran- 

 cisco. She encountered the ill-fated steamer's gale, and thus de- 

 scribes, it: '■^Decemher 24:th. Latitude 89° 15' north, longitude 

 62° 82' west. First part threatening weather; shortened sail; at 

 4 P.M. close-reefed the top-sails and furled the courses. At 8 

 P.M. took in fore and mizzen top-sails ; hove to under close-reef- 

 ed main top-sail and spencer, the ship lying with her lee rail un- 

 der water, nearly on her beam-ends. At 1 80 A.M. the fore and 

 main top-gallant-masts went over the side, it blowing a perfect 

 hurricane. At 8 A.M., moderated ; a sea took away jib-boom 

 and bowsprit cap. In my thirty-one years' experience at sea, I 

 have never seen a typhoon or hurricane so severe. Lost two men 

 overboard — saved one. Stove skylight, broke my barometer, 

 etc., etc." Severe gales in this part of the Atlantic — i. e., on the 

 polar side of the calm belt of Cancer — rarely occur during the 

 months of June, July, August, and September. This appears to 



