DISCUSSION ON CAPTAIN HUTTON's PRECEDING PAPER. 243 



culiar value. He had had opportunities ofohserving the birds of the 

 Southern ocean that were enjoyed by few. On the highly interesting 

 question of the sea birds of the Southern Ocean following ships — a fact 

 that had attracted the attention of every navigator in the South Sea 

 from the time that Coleridge's " Ancient Mariner" was written, and be- 

 fore it— Captain Hutton had thrown a great and a very curious light. 

 He (the President) perfectly agreed with the results at which he had 

 arrived from numerical calculation, as to the floating power of air cells, 

 being of opinion, with him, that it was perfectly ludicrous to attribute 

 to the influence of the heated air in those cells in the bones of the birds 

 any sustaining power for the purposes of flight or motion in the air, 

 even in the coldest latitudes. Captain Hutton's calculations, in his 

 opinion, demolished that supposition completely. It was easy to destroy 

 wrong opinions, but difficult to construct right ones on their ruins ; 

 nevertheless he thought that Captain Hutton had constructed the true 

 theory of the sailing powers of those birds in the closing observa- 

 tions of his paper, which possessed, in his mind, a great and impor- 

 tant value. The square-rigged ship, as he had stated, sails within 67° 

 of the wind, and the cutter within from 45 to 50° of it, whereas the 

 Albatross goes within 22 1° of the wind. Now, that phenomenon would 

 be perfectly inexplicable if they supposed the Albatross to " sail" upon 

 the same principles that determined the motion of the cutter or square- 

 rigged ship, when " close-hauled;" and therefore he quite concurred 

 with Captain Hutton's idea, that the original momentum of the bird 

 must be taken into account in estimating the closeness with which it 

 " sails" to the wind. The Albatross could not be so much better rigged 

 than the ship or cutter, as to be able to go so much closer than they 

 can, of its own accord, and with only the assistance of heated air in its 

 cells; it was, therefore, evident that that power in the bird was due 

 very much to the momentum acquired by muscular force in its previous 

 rapid flight. From Captain Hutton's descriptions, as well as from 

 wlret he had read concerning the flight of this bird, he had no doubt 

 that the true parallel for its motive power, as well as that of the Gannet, 

 was the steamer, and not the sailing vessel. The muscular motive 

 powers of both birds were situated, in nautical phrase, far " aft." He 

 was sorry Captain Hutton had not brought home some of the muscles 

 of the Albatross ; the skin and bones afforded much less information 

 than the soft parts. With respect to the points touched on in the ear- 

 lier part of the paper, as to the varieties of some of the birds described, 

 and as to the question of maturity or immaturity having been mistaken 

 for distinctness of species, he did not feel so competent to express an 

 opinion as some other gentlemen who were present. 



Mr. Andrews said, he had listened with much pleasure to the 

 paper j ust read by Captain Hutton, as his were views drawn from actual 

 observation of the habits and distribution of the Pelagic birds of the 

 Southern latitudes. He (Mr. Andrews), however, believed that very 



