ON THE STUDY OF NATURE. 



There is no division of the animal world in which we are more led to admire th 

 wisdom of the Supreme Being, than in the different feathered tribes. Their struc- 

 ture and habits of life are wonderfully fitted for the various functions they have to 

 perform. Their bodies are clad with feathers, which form an envelope much lighter 

 than hair. These lie over each other close to the body, like the tiles of a house ; 

 and are arranged from the fore-part backward, by which means the animals are 

 enabled the more conveniently to cut their way through the air. For this purpose 

 also the head is small and the bill somewhat wedge-shaped ; the neck is long, and 

 easily movable in all directions ; and the body slender, sharp on the under side, and 

 flat or round on the back. The bones likewise are hollow, and very light compara- 

 tively with those of terrestrial animals. For the purpose of giving warmth to th 

 body, a short and soft down fills up all the vacant spaces between the shafts of tho 

 feathers. 



Birds are enabled to rise into and move from place to place in the air, by meanii 

 of the members that are denominated wings. The muscles by which the wings ar 

 move are exceedingly large ; and have been estimated, in some instances, to consti- 

 tute not less than a sixth part of the weight of the whole body. When a bird is on 

 the ground, and intends to fly, he takes a leap, stretches his wings from the body, 

 and strikes them downward with great force. By this stroke the body is thrown 

 into an oblique position. That part o fthe force which tended upward is destroyed 

 by the weight of the bird ; and the horizontal force serves to carry him forward. 

 The stroke being completed, he moves up his wings. These being contracted, and 

 having their edges turned upward, meet with little resistance from the air. When 

 they are sufficiently elevated, the bird makes a second stroke downward, and the 

 impulse of the air again moves him forward. These successive strokes act as so 

 many leaps taken in air. When the bird wants to turn to the right or left, he strikes 

 strongly with the opposite wing, and this impels him to the proper side. The tail 

 acts like the rudder of a ship ; except that it moves him upward or downward, instead 

 of sideways. If the bird wants to rise, he raises his tail ; and if to fall, he depresses 

 it ; whilst he is in an horizontal position, it keeps him steady. 



A bird, by spreading his wings, can continue to move horizontally in the air for 

 some time, without striking them ; because he has acquired a sufficient velocity, and 

 his wings, being parallel to the horizon, meet with but little resistance. When he 

 begins to fall, he can easily steer himself upward by his tail, till the motion he had 

 acquired is nearly spent ; he must then renew it by two or three more strokes of his 

 wings. On alighting, he expands his wings and tail full against the air, that they 

 may meet with all the resistance possible. 



The centre of gravity in birds is somewhat behind the wings ; and, to counterbal- 

 ance this, most of them maybe observed to thrust out their head and neck in flying. 

 This is very apparent in the flight of Ducks, Geese, and several other species of 

 water-fowl, whose centre of gravity is further backward than in the land birds. In 

 the Heron, on the contrary, whose long head and neck, although folded up in flight, 

 overbalance the rest of the bodv, the long legs are extended, in order to give the proper 

 counterpoise, and to supply what is wanting from the shortness of the tail. 



The feathers of birds would perpetually imbibe the moisture of the atmosphere ; 

 and, during rain, would absorb so much wet, as to impede their flight, had not the 

 wisdom of Providence obviated this inconvenience by a most effectual expedient. 

 They are each furnished on the rump with two glands, in which a quantity of unctu- 

 ous matter is constantly secreting. This is occasionally pressed out by the bill, aj d 

 used for the lubrication of the feathers. The birds that share, as it were, the hal i- 

 tations of man, and live principally under cover, do not require so great a supply, 

 and therefore are not provided with so large a stock of this fluid, as thosje that rove 

 abroad, and reside in the open element. It is on this account that poultry, when 

 wet, make the ruffled and uncomfortable appearance that we observe. 



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