152 MAMMALS OF BERMUDA. 
(B. mysticetus), which, with the same regularity as the swallow, comes to 
Britain, visits the warm seas of the Bermuda Islands, where I have no- 
ticed them in large numbers, arriving regularly about the last week of 
February or beginning of March, and remaining till the beginning of 
June, and sometimes a little later; those frequenting the shallow waters 
being the cow-whales with their young, the bulls probably keeping in 
the deeper waters outside the reefs. While sailing from Bermuda to 
Nova Scotia, in the month of June, I observed large troops of the blow 
or true whale, all heading to the north, no doubt on their way from the 
Bermudas and the warmer seas.” 
It being, therefore, beyond doubt that the Right Whale does pass 
through the Gulf Stream on its southern migration to the Bermudas, it 
becomes an interesting question whether the animal is submitted to a 
higher degree of temperature while passing through the stream than it 
is while inhabiting the waters of Bermuda, in which it passes some four 
months of its existence regularly every year. We are fortunately able 
to give reliable information upon this subject, having during several 
voyages between Halifax and the Bermudas (which route, being almost 
direct north and south, is that traversed by the whales), at different 
seasons of the year, had excellent opportunities, through the kindness 
of the commanders of the royal mail steam packets, who are in the habit 
of taking observations every four hours, of ascertaining the temperature 
of the Gulf Stream at various positions, and we find that scarcely any 
difference exists in its temperature as far as regards the months of Feb- 
ruary and June, the known periods of migration, and that the highest 
degree of heat of the stream at those periods yet recorded has never 
exceeded 73°. We have next to look at the temperature of the sea im- 
mediately around the Bermudas during the months of February and 
March, when the whales arrive, and we find that it is generally about 
64°, and that of June, when they depart, about 74°; so that it is clear 
these animals are submitted to a higher degree of temperature for a 
month or more in the locality they have chosen for a winter resort, than 
they are during their passage through that supposed impassable barrier 
of heat, the Gulf Stream. Indeed, it may be said that this whale is 
capable of bearing a much higher degree of temperature, for in some 
seasons the maximum of surface temperature at Bermuda during the 
month of June has reached 78°, so that all statements hitherto made to 
the effect that the Right or Greenland Whale is unfitted to resist the 
presence of heat must be considered as wholly incorrect. 
