The Sailing-Flight of Birds

IN NATURE of February 2, Mr. Mallock remarks that the skimming of some birds near the surface of the waves, where the variations in the velocity of the wind are great, may be dependent only on the inequalities of a horizontal breeze, and that an upward current is not absolutely necessary. My own observations have led me to the conclusion that whenever a bird glides for any distance without losing altitude he is, no less than the soaring kite or eagle, utilising an upward current of air. But it is possible that Mr. Mallock may be thinking of the albatross, who is perhaps without peer in his power of profiting by the vagaries of the wind. Unfortunately, I have had no opportunities of observing the albatross, and from those who have I get very conflicting accounts, some maintaining that he will glide for long distances under conditions which make it almost certain that the wind is horizontal, others holding that, though he brings the art to greater perfection, he does nothing different in kind from what the gull, that hangs with outstretched wings over the stern of a steamer, is able to achieve.