II BOTANIC GARDEN 33 



from the two latter trees. Before seeing them, I had no idea 

 that any trees could cast so black a shade on the ground. 

 Both of them bear to the evergreen vegetation of these climates 

 the same kind of relation which laurels and hollies in England 

 do to the lighter green of the deciduous trees. It may be 

 observed that the houses within the tropics are surrounded by 

 the most beautiful forms of vegetation, because many of them 

 are at the same time most useful to man. Who can doubt 

 that these qualities are united in the banana, the cocoa-nut, the 

 many kinds of palm, the orange, and the bread-fruit tree ? 



During this day I was particularly struck with a remark of 

 Humboldt's, who often alludes to " the thin vapour which, with- 

 out changing the transparency of the air, renders its tints more 

 harmonious, and softens its effects." This is an appearance 

 which I have never observed in the temperate zones. The 

 atmosphere, seen through a short space of half or three-quarters 

 of a mile, was perfectly lucid, but at a greater distance all 

 colours were blended into a most beautiful haze, of a pale 

 French gray, mingled with a little blue. The condition of the 

 atmosphere between the morning and about noon, when the 

 effect was most evident, had undergone Ifttkchange, excepting 

 in its dryness. In the interval, the difference between the dew 

 point and temperature had increased from 7°. 5 to 17°. 



On another occasion I started early and walked to the 

 Gavia, or topsail mountain. The air was delightfully cool and 

 fragrant ; and the drops of dew still glittered on the leaves of 

 the large liliaceous plants, which shaded the streamlets of clear 

 water. Sitting down on a block of granite, it was delightful to 

 watch the various insects and birds as they flew past. The 

 humming-bird seems particularly fond of such shady retired 

 spots. Whenever I saw these little creatures buzzing round a 

 flower, with their wings vibrating so rapidly as to be scarcely 

 visible, I was reminded of the sphinx moths : their movements 

 and habits are indeed in many respects very similar. 



Following a pathway I entered a noble forest, and from a 

 height of five or six hundred feet, one of those splendid views 

 was presented, which are so common on every side of Rio. At 

 this elevation the landscape attains its most brilliant tint ; and 

 every form, every shade, so completely surpasses in magnificence 

 all that the European has ever beheld in his own country, that 



D 



