250 THE UNIVERSE. 



eyries in the midst of solitude and rocks, only employ in 

 their construction rough fragments of stick heaped up in 

 disorder; others make use of leaves and moss, which they 

 arrange with skill. But such materials are still too coarse 

 for the delicate bodies of the humming-birds, which pour 

 along in swarms. They, as for example the Serrirostris, 

 often construct for themselves a downy charming little cup 

 of cotton, wherein to shelter their jewelry of rubies and 

 topazes without sullying the lustre of them. Tavo other 

 species of the same group, which also make use of soft 

 pillows, garnish the outside of their nests with fragments 

 of lichens, doubtless to hide it better from carnivorous 

 animals. This is the case with the black-plastron or mango 

 humming-bird of BufFon. 



CHAPTEE II. 



THE INSTINCT OF CHEMISTRY. — MOUNTAIN BUILDERS AND 



GLEANERS. 



Some birds attract attention by the size of their con- 

 structions, and by the innate notions which they seem to 

 have of certain chemical phenomena which we see them 

 make exactly the right use of. 



A little hill in an English garden astonishes us by its 

 dimensions, and the labour which it demands. Many 

 hands and much time have been occupied with it, and yet 

 if we compare the work with the means of him who 

 orders it to be formed, this mass of earth seems but a little 



