WIND AND FLIGHT 133 
gliding downward and onward till he is almost 
touching the water, then suddenly he faces the wind, 
showing his white under-surface, and is lifted a few 
feet, then he glides downward and onward again, 
again faces to right or left, and is again lifted 
without any sign of effort on his part. It is 
a weird performance, more impressive than the 
Gull’s. 
There must be up-currents when required, other- 
wise the Shearwater must be superior to physical 
laws, and such a superiority we cannot concede. 
The waves give to the wind the upward incline that 
is wanted; even a small obstruction will cause a 
very considerable deflection (see p. 134). Advancing 
at something like a right angle to the wind, he feels 
an up-current as he is gliding downward and onward 
and at once turns and faces it ; thus he gains altitude 
and can begin another onward glide. And so he is 
able in most methodical style to cover large tracts 
of sea. Gannets may be seen employing the same 
method in British seas, and, no doubt, Shearwaters 
also, though I have seen them chiefly in the Mediter- 
ranean, where they are common. As a rule I have 
geen them advancing in this style at a considerable 
angle to the wind, but they sometimes employ the 
same method for an advance in the teeth of the 
wind. There is no reason why the Shearwater and the 
Gannet, having the waves and the resulting up- 
currents to assist them, should not do what Gulls 
do behind a steamer when there is a wind blowing 
across the vessel’s course—I am speaking of the 
clever performance described above (see fig. 25, 
p. 131), The Shearwater and the Gannet have at 
