i8jz] BOTANIC GARDEN. 23 



supporting surface with such force, that the insect by the reaction was 

 jerked upwards to the height of one or two inches. The projecting 

 points of the thorax, and the sheath of the spine, served to steady 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 

 contraction, without the aid of some mechanical contrivance. 



On several occasions I enjoyed some short but most pleasant excur- 

 sions in the neighbouring country. One day I "went to the Botanic 

 Garden, where many plants, well known for their great utility, might 

 ba 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 vege- 

 tation, 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 

 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 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 top- 

 sail 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 aa 

 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 befglit of 

 five or six hundred feet, one of those splendid views was presented; 



