19 
on the migration of birds. 
their wings as to prevent their flying, and we should see 
them occasionally in this disordered state fluttering on the 
shore. If they went to the sea side, and got beyond the reach 
of the eye to inure themselves to this element, how could 
they return, divested as they must be either of the means of 
swimming or flying ? Whoever has observed the common 
tame duck driven to the necessity of repeatedly diving from 
the pursuit of a water-dog, must have noticed how exhausted 
it rises to the surface of the water after a short period of sub- 
mersion, and how incapable it is of flying, in consequence of 
the soaking of its wings. The same may be said of birds 
more in the habit of diving, the grebes and divers. When 
entangled in a net they soon perish, or when they happen to 
dive under ice that may chance to overspread a pond ; no 
uncommon place of resort for some of the smaller species of 
grebes. 
I have always been much attached to that faithful animal, 
the Newfoundland dog, and have often procured from that 
country those dogs that had been much accustomed to diving, 
and which had been kept to the practice ; yet I never ob- 
served that any of them attained by habit the power of re- 
maining under water longer than thirty seconds, and even 
then, on rising to the surface, they appeared confused. Ne- 
groes and other men who have been employed in seeking 
among sunken rocks the hidden treasures of the deep, are said 
to have acquired a habit of remaining some minutes under 
water, but the time was probably measured by a rude guess, 
and not by a stop watch. 
Having thus called the attention of the Society to such 
statements as give support to the fact of migration, and 
