Chapter XVII: Climate, Geology, Botany, Etc

Elsewhere in this work I have briefly pointed out the main features in the physical geography of the Kilima-njaro region, the dry, almost uninhabited plains, covered with coarse yellow grass and stunted trees, save where perennial streams induce rich vegetation; the misty snow-capped mountains, where the damp climate causes a verdure and a freshness reminding us of the fairest portions of our own island; the majestic forests that clothe certain districts like Taveita, or, not far distant, the broad flats white with natron-salt, the beds of dried-up lakes. With a country offering such very diverse features there are naturally wide ranges of temperature and an infinite variety of climate. Two days’ climb on Kilima-njaro will transfer you from equatorial heat to Arctic cold. You may change your surroundings in this short period from the tropical vegetation of Taveita to a lifeless wilderness of ice, rocks, and snow. Midway up the mountain there are lovely regions, mild, equable, and moist, with a climate resembling a Devonshire summer. Here the intense verdure and the luxuriance of fern life testify to the constant showers of gentle rain. A few thousand feet below, in the salt plains, you may be parched and scorched by the hot desert winds, recalling—though in a much modified degree—the sirocco or khamsīn of Northern Africa. In the forests of Taveita the (to me, not disagreeable) unvarying, moist, greenhouse warmth of the tropical lowlands awaits you. Here, perhaps, the utmost range of the thermometer during the twenty-four hours will be ten or twelve degrees. In the outer plains it may vary from 91° in the early afternoon to 58° before dawn.

During the four months (June—September) of my stay in Moši, at an altitude of 5000 feet, the average readings in the shade of the thermometer were as follows: At noon, 71°; at 8 p.m., 60°; at 6 a.m., 58°. The lowest reading at noon was 68° (August 12th); the highest 80° (July 3rd and June 12th). The lowest reading at night (from 10 to 12 p.m.) was 54°; the highest 62. In my more elevated collecting stations, at 10,000 and 11,000 feet, the lowest night temperature (recorded) was 29°; the highest at 3 p.m., 65°. At Taveita the highest registered was 90° at 3 p.m.; the lowest at 4 a.m., 60°. The highest temperature ever recorded in the plains between Kilima-njaro and the coast was 91°.

From these observations the reader will perceive that, for at least six months of the year, the temperature of this portion of Eastern Africa is quite bearable, if not in some places delightful. Nowhere is there extreme heat, and the nights are always so far cool, that bedclothes are supportable and sleep is refreshing. What it is for the other half of the year I cannot personally say, as I have had no experience, but travellers and missionaries who know the adjacent countries assure me that the temperature is but little higher during the other months when the wet season prevails; it is rather that the climate becomes everywhere more equable, and the thermometer does not descend so relatively low at night.

The seasons that prevail over this district are also influenced by local surroundings. Close to the coast the rains commence in October, intermit from December to March, and return in all their force during April and May. The true “dry season” is from June till October, during which not a drop of rain falls, though the sky is often clouded. Between the coast country and the elevated plateau about 100 miles inland there is a district which is much stinted in its rainfall, except where unusually high mountains arrest the moisture-laden winds from the Indian Ocean. There we arrive at the most general type of African scenery—wide, rolling savannahs, covered with grass and scattered clumps of trees. These extend, here and there broken by mountain ranges, to the shores of the Victoria Nyanza, and over all this district the rainfall is generally limited to the months of November, December, March, April, and May. On the western shores of the Nyanza Lake rain falls during ten months of the year, a contrast to the regions lying in the same latitudes between the Victoria Nyanza and the Indian Ocean. In all lofty plateaux or high mountain ranges the rainfall is very different to what it is in the plains below. Thus in Kilima-njaro it rains more or less throughout the year. My residence there was during the dry season, yet, nevertheless, in the month of June I had to record six days of rain; in July, 8; in August, 9; in September, 7; in October, 8; and in the first half of November, 5. The real rainy season is from November to May, but the Wa-čaga inform me that there is seldom at any season a continuous heavy downpour, but rather a greater or less frequency of showers.

In the plains, however, near the mountain, the fall of rain is torrential, and is equal in violence to what one usually meets with in the tropics.

While snow is never absent from either of the twin summits of Kilima-njaro, and, indeed, at all times covers the upper part of the dome of Kibô with a mantle of unvarying white, yet the quantity and downward extent of the snows vary almost daily, even in the dry season. After a rainy night in the lowlands, the snow on the following morning may be seen on Kibô down to a level of 14,000 feet, and even a little lower on the western slope, while the whole of craggy Kimawenzi is a pinnacle of scintillating whiteness, like—to use a very hackneyed simile—a sugarloaf. Yet if the succeeding day be warm and sunny, the snow on Kimawenzi may shrink in twenty-four hours to a tiny patch and a streak in between the jagged walls of black rock, while on Kibô it will withdraw its inroads 1000 feet above the level of the day before. On the whole, the least snow observable is during the months of July and August. In October there is a great deal. I should think the most snow fell, from what I hear by native report, during February and March, but at this time, nevertheless, the natives maintain that an ascent of the mountain is easiest, as the mists are not so frequent. Neither is the cold so great, curiously enough.

Snow is reported occasionally to fall on the summit of Mount Meru, the pyramidal peak lying to the south-west of Kilima-njaro, and on its western slope to lie for some months. The western slopes of Kibô and Kimawenzi are much more snow-covered than the eastern, and the snow extends to lower levels.

Doubtless the perpetually melting snow is the cause of the many streams which issue from the sides and base of Kilima-njaro. Nevertheless, it is curious, considering that the snow-clad peaks slope to all the quarters of the compass, that the streams flowing from the mountain should be principally confined to its southern aspect. From the north of Kilima-njaro not a stream descends, although some thirty miles from its summits, in the plains of Ṅgiri, there is an extensive marsh, sometimes, in the rainy season, almost becoming a lake. To the west of the mountain, one stream, the Eṅgare Nairobi (cold water), flows to an unknown bourn, possibly ending in the great salt marsh or swamp of Eṅgaruka. On the eastern versant, start the various rivulets of Useri, Kimaṅgelia, and others which go to form the Tzavo, a river entering the Indian Ocean at Malindi. The River Lumi, flowing through Taveita and into Lake ǰipé, also rises on the eastern side of Kilima-njaro; but none of these streams, already mentioned, start from the higher levels of the mountain. They either issue at once, or only well forth in full volume at its base. Thus the Lumi is generally represented as rising some distance up the mountain in the country of Rombo. In a measure this is correct, for the dry bed of the stream is there, and this occasionally in the wet season is filled by a torrent, but at most times it does not show a drop of water, and it is only when one has quite descended the mountain and reached a level of 2000 odd feet—the level of the surrounding plain—that the Lumi suddenly issues full-grown from its dry bed. A mile from where it first appears in a series of puddles, it is scarcely fordable. On the southern side of Kilima-njaro, however, it is very different. Here two large streams commence to flow close to the snow-line, one rising near the base of Kibô, and the other near the base of Kimawenzi. Myriads of other rivulets intersect this hilly region of Čaga, which between 6000 feet and 3000 feet is well populated and under considerable cultivation. The most perfectly-watered and most fertile country is, strangely enough, without inhabitants, namely, the districts lying to the south-east of Kimawenzi, described in Chapter XIV. All these streams flowing from the south and south-east of Kilima-njaro form the River Ruvu (Luvu of the Wa-taveita, and Ruvu of the Wa-zeguha), which enters the Indian Ocean at Pangani.

The greatest extent of the elevated mass of Kilima-njaro is about sixty miles, from north-west to south-east.

That this huge mountain-mass is nothing but the result of past volcanic activity has been well shown by Mr. Thomson. He conjectures that Kimawenzi was the original outlet of the volcano, but that when, in course of time, its peak had been raised higher and higher by the accumulation of lava-flow and ashes, and the subterranean forces sought another and easier outlet, the mightier crater of Kibô was formed, which ultimately towered above its older rival, and in its turn grew too high for the escape of the imprisoned matter, which found fresh vents in the many minor craters on the mountain-side. Now, though there are still traditions of slight earthquake shocks having occurred within the last two or three generations of inhabitants, there has been no further manifestation of volcanic activity, and the great snowcrowned volcano has probably entered a peaceful old age.

NOTE BY PROFESSOR T. G. BONNEY, DR.SC., LL.D., F.R.S.,

PRESIDENT OF THE GEOGRAPHICAL SOCIETY,

_On a Small Collection of Rocks brought from the Higher Regions of
Kilima-njaro by Mr. H. H. Johnston_.

No. 1.—Subangular fragment of smooth, compact, nearly black rock;
appears as if somewhat waterworn; fracture rather conchoidal. A
_glass-basalt_, or possibly one of the more _basic augite-anderite_.
14,000 feet. Central ridge of Kilima-njaro.

No. 2.—Subangular fragment, somewhat rounded in outline; appearance
like No. 1; colour rather light; and a few small scattered crystals of
whitish _felspar_ visible; more probably an _augite-anderite_. 14,000
feet. Central ridge of Kilima-njaro.

Nos. 3–5.—Flattened fragments, with a rather platy, more or less
scoriaceous structure; fragments of a lava flow; probably
_augite-anderite_. 14,000 feet. Central ridge of Kilima-njaro.

No. 6.—A dull, dark-grey rock, with numerous small scattered crystals
of either _hornblende_ or _augite_. I believe the former. Probably a
_hornblende-anderite_; at any rate, it is almost certainly an
_anderite_ of some kind, and one of those which are near the basalts.
The specimen is a large slab. 14,700 feet. Base of Kimawenzi.

Nos. 7–14.—Fragments of rock and mineral. The rocks, which are rather
decomposed, appear to be of volcanic origin, and most contain rather
large crystals of the mineral sent with them. This is a rather
peculiar form of _felspar_, the sort probably _anderite_. 14,000 feet.
Base of Kibô.

Nos. 15, 16.—Decomposed, scoriaceous in part, with generally compact
shapes. Dark in colour. Contain rather large crystals of the
above-named _felspar_, which is probably a variety of _anderite_.
14,000 feet. Central ridge.

No. 17.—A crystal, fairly well-preserved, about 1½ inch long.
Apparently it is a _felspar_, but the form is certainly an exceptional
one. From its form I should suppose it to belong to the monoclinic
system, and was bounded by basal clinopinacoidal and prismatic planes;
but I do not remember to have seen a sanidine (or indeed any other
felspar) crystal of this form, and suspect it will prove to be a
_plagio-clastic felspar_. 14,000 feet. Central ridge.

No. 18.—Rolled pebble of dark scoria, with crystals sometimes nearly
an inch long and ⅛ inch thick, of a glassy mineral, probably
_felspar_, perhaps _sanidine_. 13,000 feet. Stream-valley on southern
slope of Kilima-njaro.

Nos. 19, 20.—Fragments less rounded, of a similar sort, perhaps less
scoriaceous. From same place as above.

No. 21.—A similar fragment, but rather more glassy-looking, with a
“ropey” structure, and containing smaller crystals. 13,000 feet.

No. 22.—Rounded pebble, dark _scoria_. 13,000 feet.

Nos. 23–33.—Fragments. Varieties of a dark, more or less vitreous
_lava_, which I think in chemical composition is likely to agree
rather with an _augite-anderite_ than a _basalt_. 13,000 feet.
Stream-valley.

No. 34.—A pebble, dark _lava_, with small grey _felspar_ crystals.
13,000 feet. Stream-valley.

Nos. 35–37.—A dark compact lava, containing elongated _felspar_
crystals as above. 14,000 feet.

Nos. 38, 39.—Rather decomposed. A dark subvitreous _lava_, with
crystals of _felspar_, similar to those from base of Kibô. 15,000
feet. Rocks from base of Kimawenzi.

No. 40.—Similar to preceding specimens, but rather paler in colour
softer, and more decomposed. Same locality.

Nos. 41–43.—Stones from Kimawenzi. Similar to last-named. 14,800 feet.

The _flora_ of Kilima-njaro is naturally interesting, as may be imagined from the extraordinary range of climate between the eternal snows of the summits and the hot tropical plains at the base. The vegetation on the coast is fairly rich and luxuriant, and typical of the tropics. There are fine forest trees—acacias, figs, baobabs, bombaxes, calophyllums, and others, while the mango has been introduced from India, and become wild. The pandanus grows in marshy places; cycads are occasionally seen, and among palms the Cocoa-nut, the Borassus, the _Hyphæne thebaïca_ (branching palm), several kinds of Raphia, Elaïs, and wild Date. At the commencement and close of the rainy season the ground is covered with vividly-coloured wild flowers. Blue clitoreas, blue commelynas, crimson, white, yellow, purple, and pink hibiscuses, lovely epiphytic orchids, white, spotted, and green, and ground-orchids of the genus _Lissochilus_—crimson-mauve and sulphur-yellow. Altogether, as I have often declared, Tropical Africa differs apparently from the other parts of the tropics in displaying splendid shows of bright-coloured flowers which really surpass anything we meet with in the temperate zone.

Inland, however, a short distance from the coast this wealth of vegetation ceases as we cross the somewhat dreary “Nyika,” or wilderness, a country poorly provided with water, and uncertain in its rainfall. But as soon as the beneficent influence of the giant mountains makes itself felt in moisture-laden breezes and dew-dropping mists, then Flora revives, and puts forth all her strength. In such places like Taveita the wealth of vegetation and the grandeur of the forest trees is inspiring. You feel carried back from our age of mean development to some past epoch, when vegetable life was on a scale with the strange, huge animal forms which marked the lusty earth’s creative prime.

Fig. 63.—_Musa Ensete_, a wild Banana.
]

The lower slopes of Kilima-njaro are exquisitely green, and scarcely a patch of earth remains uncovered, but the general aspect of vegetation recalls our English Devonshire and not the tropics. Bushy trees crown the hill-tops, or choke the narrow valleys. The grassy downs are covered with patches of bracken and scented with a low-growing mint. The native lanes are bordered with brambles and magnificent ferns, some of which belong to common European genera. There are besides other things more properly African which do not mind the colder climate of the uplands, such as dracænas, aloes, strychnias, balsams, and ground-orchids. In some of the stream-valleys the _Musa_ _Ensete_, a wild banana, grows luxuriantly up to about 6000 feet and down to 3000 feet, or a little lower if there is water. It is also met with in the Taveitan forest at the base of Kilima-njaro. It seems to be in fruit at all seasons of the year, but the bunch here illustrated was cut in September. The colour of the ripe fruit is a pale orange. The length about 3½ inches. Inside there are varying rows of seeds, from two to five or more, and in each row there may be either two, three, four, five, six, or seven seeds. Each seed is irregularly shaped, about ½ inch in diameter, and very black. The pulp which surrounds and closely adheres to the seeds is _orange_ in colour, when fresh, and somewhat pithy in texture, although very glutinous. The inside of the seeds is a friable white pith, easily rubbed into a white powder by the natives. When in this state it is used for divinations and augury. Blown from the palm of the hand into the air, its capricious wafting by the breeze is supposed to indicate the direction of an expected attack during war, or the most favourable quarter in which to travel for commerce. The thin pulp of this fruit is just eatable; faintly sweet, but leaving a somewhat acrid taste in the mouth like an unripe banana of the cultivated species. Its structure is somewhat curious, for it is composed of long veins at wide intervals, and in between are thin delicate lines running at right angles. It is supposed by the natives that children grow up fine and tall if they eat the pulp of _Musa Ensete_.[35] The natives recognize its relationship to the cultivated banana.

At a height of 7000 to 8000 feet tree-ferns may be met with, belonging to the species _Lonchitis pubescens_ (illustrated on p. 231). Then above that the arborescent heaths begin to appear, and the orchilla lichen covers nearly all the forest with a grey-green veil. Between 8000 and 9000 feet the giant Senecios are met with (a new species, illustrated in