30 RIO DE JANEIRO. [CHAP. H. 



Ou several occasions I enjoyed some short but most pleasant 

 excursions in the neighbouring country. One day I went to the 

 Botanic Garden, where many plants, well known for their great 

 utility, might be seen growing. The leaves of the camphor, pepper, 

 cinnamon, and clove trees were delightfully aromatic; and the 

 bread-fruit, the jaca, and the mango, vied with each other in the 

 magnificence of their foliage. The landscape in the neighbourhood 

 of Bahia almost takes its character 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 vegeta- 

 tation 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 arc sur- 

 rounded 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, without 

 changing the transparency of the air, renders its tints more har- 

 monious, 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 per- 

 fectly lucid, but at a greater distance all colours were blended into 

 a most beautiful haze, of a pale French grey, mingled with a little 

 blue. The condition of the atmosphere between the morning and 

 about noon, when the effect was most evident, had undergone little 

 change, excepting in its dryness. In the interval, the difference be- 

 tween 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 aud 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 

 rapidity as to be scarcely visible, I was reminded of the sphinx 

 moths: their movements and habits arc indeed in many respects 

 Very similar. 



