VISION. 15 



extended front, so as to enable them to survey 

 hundreds of acres at once. On the contrary, when 

 the land is richly covered with food, or the trees 

 abundantly hung with mast, they fly low in order to 

 discover the part most plentifully supplied. Their 

 body is of an elongated oval form, steered by a long 

 well-plumed tail, and propelled by well-set wings, 

 the muscles of which are very large and powerful 

 for the size of the bird. When an individual is seen 

 gliding through the woods, and close to the observer, 

 it passes like a thought, and on trying to see it 

 again, the eye searches in vain ; the bird is gone." 

 41 As soon/' he adds, " as the pigeons discover a suffi- 

 ciency of food to entice them to alight, they fly round 

 in circles reviewing the country below. During their 

 evolutions on such occasions, the dense mass which 

 they form exhibits a beautiful appearance as it changes 

 its direction, now displaying a glistening sheet of 

 azure, when the backs of the birds come simultaneously 

 into view, and anon suddenly presenting a mass of 

 rich deep purple. They then pass lower over the 

 woods, and for a moment are lost among the foliage, 

 but again emerge and are seen gliding aloft*." 



The return of the carrier pigeon from such distances 

 to its home is, we think, most plausibly accounted for 

 by its flying in circles ; but that there may be some 

 other manner in which it is directed, is not improbable 

 from what takes place among quadrupeds. Instances, 

 for example, are not uncommon of cats having returned 

 of their own accord to the place from which they have 

 been carried, though at the distance of many miles, 

 and even across rivers, where they could not possibly 

 have had any knowledge either of the road or of the 

 direction that would lead them to it. " The nature of 

 this beast," says Gesner, u is to love the place of her 

 breeding ; neither will she tarry in any strange place, 

 * Ornith. Biogr. p. 323. 



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