424 BIRDS OF AUSTRALIA. 



body to the horizon, according to the rate at which he is mov- 

 ing through the air. 



"Dr. Bennett, in his 'Gatherings of a Naturalist ' (p. 78), 

 gives a diagram explanatory of the flight of the Albatros," con- 

 tinues Capt. Hutton ; and, if I understand him rightly, says 

 that " it cannot sail directly against the wind, but only in the 

 way which sailors call ' close-hauled.' This diagram represents 

 a square-rigged ship sailing six points from the wind, a cutter 

 sailing four and a half points, and an Albatros flying two 

 points from the wind ; from which I infer, although he does 

 not expressly say so, that he considers that the wind helps 

 forward the Albatros in the same way that it does the ships. 

 But that this is erroneous is apparent at a glance. A ship 

 can sail at an acute angle with the wind, because the pressure 

 of the wind against its sails being met by the resistance of the 

 water is resolved into pressures having other directions. Ad- 

 vantage of this being taken by trimming the sails, it ultimately 

 results that the ship is moved in the direction of least resist- 

 ance, viz. forwards. If, however, the pressure of the wind 

 had not been met by the resistance of the water, no resolution 

 of it into other directions could have taken place. For this 

 reason a balloon can only drift with the wind, and the same 

 would be the case with the Albatros. Moreover, the state- 

 ment that he cannot sail against the wind is incorrect, 

 as Dr. Bennett himself said in his first book, ' Wanderings 

 in New South Wales ; ' the truth being that he is more 

 often seen sailing in this direction than in any other, for the 

 simple reason that as he moves slower against the wind than 

 with it, he is obHged to keep going for a longer time in the 

 former direction than in the latter, in order to retain his posi- 

 tion near the stern of the ship. However, when sailing 

 against the wind the position of his wings, body, and tail, slant- 

 ing a little downwards, is somewhat analogous to the sails of a 

 ship close-hauled, or, still better, to the position of a kite in 

 the air ; the momentum of the bird taking the place c*f the 



