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 

 seen 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 



