48 On the prevailing Storms of the Mantic Coast. 



last and most dreaded portion of the receding storm.* A spirited 

 and graphic description of this remarkable and well known crisis of 

 a hurricane, constitutes a leading feature in almost every well wrought 

 description of a marine tempest. 



We have assumed that the leading storms of the northern and 

 western Atlantic, and the American coast, originate in detached and 

 gyrating portions of the northern margin of the trade winds, occa- 

 sioned by the oblique obstruction, which is opposed by the islands to 

 the direct progress of this part of the trades, or to the falling in of tl)e 

 northerly and eddy wind from the American coast upon the trades, 

 or to these causes combined. Were it not for the fear of ranging 

 beyond the limits of established data, we might follow out this part 

 of the subject so far as to enquire after the probable influences which 

 indicate or govern the succession of periods in which these aerial 

 masses thus fall into a" state of gyration, and the probable ejSect of 

 this gyration upon each successive poruon of the trade wind which 

 may follow in the same course. If we venture on this ground, we 

 would say that the most probable indication of the separations which 

 we suppose to occur from this parallel of the trade, would be found 

 in the diurnal influences to which they are exposed, these being 

 among the most powerful causes which mark the production of me- 

 teorological phenomena, or, in other words, that such a portion of 

 the passing atmosphere would be likely to become detached in one 

 body, as should arrive at, or pass a given meridian of the obstruction, 

 in the course of an entire day. The extent of this influence on the 

 atmosphere, if subject to a progressive rate of sixteen miles an hour, 

 which is near the average advance of the storms in that region, 

 would be something short of four hundred miles from east to west. 



* To the southward of Newfoundland, shifts of wind are very common, and it fre- 

 quently happens that, after blowing a gale upon one point of the compass, the wind 

 suddenly shifts to the opposite point and blows equally strong. It has been known, 

 that while one vessel has been lying-to in a heavy gale of wind, another, not more 

 than thirty leagues distant, has at the very same time been in another gale, equally 



heavy, and lying-to, with the wind in quite an opposite direction. In the 



year 1782, at the time the Ville de Paris, Centaur, Ramilies, and several other 

 ships of war, either foundered or were rendered unserviceable, in lat. 42° 15', 

 Ion. 48° 55', on or near the Banks, together with a whole fleet of West Indiamen, 

 except five or sis, they were all lying-to, with a hurricane from east south-east ; 

 the wind shifted, without any warning, to north north-west and blew equally heavy, 

 and every ship lying-to under a square course foundered. — Purdy's J\femoir, 6th 

 edition, London, 1829, corrected from Medical Repository. 



