362 
DARWINISM 
CHAP. 
a very small portion of mud may serve to convey seeds, and 
such an occurrence repeated even at long intervals may greatly 
aid in stocking remote islands with vegetation. Many seeds 
also adhere to the feathers of birds, and thus, again, may be 
conveyed as far as birds are ever carried. Dr. Guppy found 
a small hard seed in the gizzard of a Cape Petrel, taken about 
550 miles east of Tristan da Cunha. 
Dispersal of Seeds by the Wind. 
In the preceding cases we have been able to obtain direct 
evidence of transportal ; hut although we know that many seeds 
are specially adapted to he dispersed by the wind, we cannot 
obtain direct proof that they are so carried for hundreds or 
thousands of miles across the sea, owing to the difficulty of 
detecting single objects which are so small and inconspicuous. 
It is probable, however, that the wind as an agent of dispersal 
is really more effective than any of those we have hitherto 
considered, because a very large number of plants have seeds 
which are very small and light, and are often of such a form 
as to facilitate aerial carriage for enormous distances. It is 
evident that such seeds are especially liable to be transported 
by violent winds, because they become ripe in autumn at the 
time when storms are most prevalent, while they either lie 
upon the surface of the ground, or are disposed in dry capsules 
on the plant ready to be blown away. If inorganic particles 
comparable in weight, size, or form with such seeds are 
carried for great distances, we may be sure that seeds will also 
be occasionally carried in the same way. It will, therefore, 
be necessary to give a few examples of wind-carriage of small 
objects. 
On 27th July 1875 a remarkable shower of small pieces of 
hay occurred at Monkstown, near Dublin. They appeared 
floating slowly down from a great height, as if falling from a 
dark cloud which hung overhead. The pieces picked up were 
wet, and varied from single blades of grass to tufts weighing 
one or two ounces. A similar shower occurred a few days 
earlier in Denbighshire, and was observed to travel in a 
direction contrary to that of the wind in the lower atmosphere. 1 
There is no evidence of the distance from which the hay was 
1 Nature (1875), vol. xii. pp. 279, 298. 
