BIRD-FLYING. 
61 
myfelf with merely remarking that in my view the fcrew 
is a miflake , whether in water or air. 
I come now to what, for want of fome better way of 
expreffing it, I have ventured to call paffive locomotion. 
And to this I alk the reader’s fpecial attention. It is the 
paffive locomotion of birds in the air, the moft interefting 
light, and, in the abfence of a clear perception of what 
flying actually conlifts in, the moft extraordinary poffible 
to conceive of, fo very extraordinary that even Profelfor 
Marey only admits it as a fadt becaufe of the teftimony of 
the many who have witneffed it. My motive for alking 
the reader’s fpecial attention to this is becaufe of the ufe 
I intend to make of it in illuflration of the polition I 
have affumed with refpedt to the readtive indirect or 
paffive locomotion of the dragon-fly and creatures of its 
clafs. 
The Atlantic voyager who cares more to watch the 
birds than his fegar as he walks the deck of his fleamer, 
will obferve, as he approaches the Britifli coaft, immenfe 
numbers of fea-gulls, of apparently all ages and flzes, 
following in the wake of the fhip : fome wheeling upwards, 
fome diving downwards; at one moment miles ahead; and 
at another moment, miles behind: a bevy of them always 
hovering near the flern of the veflel, on the look-out for 
any ftray bits from the fhip’s larder or ftores that may be 
thrown overboard. At fuch times nothing can exceed the 
dexterity of the creatures : the fuddennefs with which they 
