1832.] A TROPICAL ATMOSPHERE. 43 



the whole body during the spring. In the descriptions 

 which I have read, sufficient stress does not appear to 

 have been laid on the elasticity of the spine : so sudden 

 a spring could not be the result of simple muscular con- 

 traction, without the aid of some mechanical contrivance. 



On 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 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, without 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 little change, 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 



