VELOCITY OF MUSCULAR CONTRACTION. 417 



months; but if we attend to their excessive velocity, the difficulties, in 

 a great measure, vanish. "Nothing," says Wilson, 1 "is more common 

 in Pennsylvania than to see large flocks of the bluebirds, in spring and 

 fall, passing at considerable heights in the air, from the south in the 

 former, from the north in the latter season. The Bermudas are said to 

 be six hundred miles from the nearest part of the continent. This may 

 seem an extraordinary flight for so small a bird ; but it is a fact that it 

 is performed. If we suppose the bluebird to fly only at the rate of a 

 mile a minute, which is less than I have actually ascertained them to 

 do over land, ten or twelve hours would be sufficient to accomplish the 

 journey." Montagu, a celebrated ornithologist, estimates the rapidity 

 with which hawks and many other birds occasionally fly to be not less 

 than one hundred and fifty miles an hour ; and that one hundred miles 

 per hour is certainly not beyond a fair computation for the continuance 

 of their migration. Major Cartwright, on the coast of Labrador, found 

 by repeated observations, that the flight of the eider duck is at the rate 

 of ninety miles an hour; yet it has not been esteemed very remarkable 

 for its swiftness. Sir George Cayley computes the rate of flight of the 

 common crow at nearly twenty-five miles an hour. Spallanzani found 

 that of the swallow about ninety-two miles an hour; and he conjectures, 

 that the velocity of the swift is nearly three times greater. A falcon 

 belonging to Henry IV. of France escaped from Fontainbleau, and was 

 in twenty-four hours afterwards at Malta, a distance computed to be not 

 less than one thousand three hundred and fifty miles, making a velocity 

 of nearly fifty-seven miles an hour, supposing the falcon to have been 

 on the wing the whole time ; but, as such birds never fly by night, if 

 we allow the day to have been at the longest, his flight was perhaps at 

 the rate of seventy-five miles per hour. It is not probable, however, as 

 Montagu observes, that it had either so many hours of light in the 

 twenty-four to perform its journey, or that it was retaken at the moment 

 of its arrival. 2 A society of pigeon-fanciers from Antwerp despatched 

 ninety pigeons from Paris, the first of which returned in four hours and 

 a half, at a rate of nearly fifty miles an hour. Out of one hundred and 

 ten pigeons, carried from Brussels to London in the summer of 1830, 

 and let fly from London on July 19th, at a quarter before nine A.M., 

 one reached Antwerp, one hundred and eighty-six miles distant, at 

 eighteen minutes past two, or in five and a half hours, being at the 

 rate of nearly thirty-four miles an hour. In another case, one went 

 from London to Maestricht, two hundred and sixty miles, in six and a 

 quarter hours. In January, 1831, two pigeons, carried from Liskeard 

 to London, were let loose in London. One reached Liskeard, two hun- 

 dred and twenty miles distant, in six hours ; the other in a quarter of 

 an hour more. 3 There is an instance of the migratory or passenger 

 pigeon Oolumbamigratoria of Wilson having been shot in Fifeshire, 

 in Scotland. It was the first ever seen in Great Britain, and had been 

 forced over, it was imagined, by unusually strong westerly gales. 4 



1 American Ornithology, ii. 178. 



2 Fleming's Philosophy of Zoology, ii. 42, Edinb., 1822. 



3 Turner's History of the World, Amer. edit., i. 259, New York, 1832. 

 * New Monthly Magazine for 1826. 



VOL. I. 27 



