124 



not owino- to ordinary causes, and that we must look to some 

 extraordinary means to solve the mystery. From a very ex- 

 tended series of observations made at intervals during the last 

 twenty years, with the view of throwing light upon the migra- 

 tion of North American birds to those islands, we have become 

 impressed with the fact that the largest nights of birds occur 

 there durino- the period of great atmospheric disturbance. 

 From the Utter end of September to that of October, violent 

 revolving gales are prevalent throughout the region which com- 

 prises the east coast of the Southern and Middle 1 States and 

 the North Atlantic in those latitudes, for some 600 or 800 miles 

 from land. At this particular period vast flights of birds of all 

 kinds are proceeding southward along the coast for their winter 

 resorts in Florida, West Indies and South America, and must 

 often meet with the violent gales we have alluded to. Now 

 the observations of scientific aeronauts, like Glaishier and 

 others, teach us that the upper atmosphere is composed! of cur- 

 rents of air differing in their courses as elevation proceeds, and 

 some cases are on record in which balloons at a great height 

 have suddenly come in contact with violent direct gales, which 

 carried them onward with such velocity as to render their 

 course one of extreme peril, only escaping destruction by the 

 superior manoeuvring of those in charge. Let us suppose a 

 violent revolving gale passing along the coast of the Southern 

 States, about the latitude of the Bermudas, during the period 

 of the autumnal migration of birds and butterflies, engulphing 

 some of those great flights which are then proceeding along in 

 a southerly direction. Drawing them up high in its vortex, a 

 direct westerly gale is met with,, blowing with great force out to 

 sea. Hurled with- amazing rapidity along this cool aerial cur- 

 rent, in the course of about three or four hours the heated va- 

 por arising from the Gulf Stream would be met with, and 

 would it be considered as too imaginative to grant that the 

 ascending warmth of that stream has power sufficient to ameli- 

 orate the condition of the cool current, to stay its rapid course 



iTtrias lisa occurs along the Atlantic Coast from. New Hampshire to Cuba. It is 

 excessively rare north of Cape Cod, common from New Jersey to Cape Hiatteras, and 

 extremely abundant farther South. — «S. H. S. 



