187 
Natural History. -^Botany. 
rock-crystal is impregnated with oxygen, like that observed in 
some springs, and that the superincumbent air is azote. 
BOTANY. 
36 . Distribution of Vegetables in Madeira. — Kuhl, during his 
stay in Madeira, was enabled to obtain a general conception of the 
distribution of its vegetables ; and the following is an abstract of 
the different vegetable zones observed in ascending from the sea^. 
shore to the higher parts of the island. — 1 . Region of the Cacti. 
This region extends from the sea-shore to the height of 630 feet. 
Here the Cactus and Ficus indica grow on the rugged rocks, 
and the vine, sugar cane, arum, and other fruits of southern 
climes, in the fields. This region is also abundant in wild 
plants, he. of various descriptions. — 2. Region of the Vine. The 
cultivation of the vine commences on the sea^shore, and the cac- 
ti accompany it to the height of 630 feet. The vine ascends 
to an elevation of 2030 feet ; but above this elevation the vine 
no longer bears ripe fruit. The arum, sugar-cane, mulberry, po^ 
tato, and allium, are cultivated; but neither cactus nor banana are 
here met with. Agriculture is more extensively followed in this 
than in any other region. — 3. Region of the Chesnui-tree. The 
lower edge of this region is 2300 feet above the sea, and is dis- 
tinguished by its lofty trees, which are found to the height of 
2950 feet. At a greater elevation, they are small, and no longer 
bear fruit. — 4. Region of the Genista. In this region, whose upper 
limit is 3920 feet high, whole tracts are covered with genistas. 
— 5. Region of Heaths. This zone extends to the summit of 
Pico-Ruwa, which forms the highest peak in the island, and 
which is reckoned 5300 feet above the level of the sea, and, as 
its name implies, abounds in heaths. 
ZOOLOGY. 
37 . Dr Mschdlz on Sheletons of Insects. — Dr .^scholz has 
lately described what he considers as an internal skeleton, which 
he detected in several tribes of the class Insecta ; and the same 
naturalist has published some new views in regard to the struc- 
ture of the heart, particularly of the right ventricle. 
38. M. KuhVs Zoological Observations. — From the observations 
of M. Ruhl, it appears that the bones of the Cape Petrel (Pro- 
