Pongo-land ignores all such artificial partitions as districts or parishes; the only divisions are the countries occupied by the several tribes.
The Gaboon lies in "Africa-on-the-Line," and a description of the year at Zanzibar Island applies to it in many points.[6] The characteristic of this equatorial belt is uniformity of temperature: whilst the Arabian and the Australian deserts often show a variation of 50° Fahr. in a single day, the yearly range of the mercury at Singapore is about 10°. The four seasons of the temperates are utterly unknown to the heart of the tropics—even in Hindostan the poet who would sing, for instance, the charms of spring must borrow the latter word (Buhar) from the Persian. If the "bull" be allowed, the only rule here appears to be one of exceptions. The traveller is always assured that this time there have been no rains, or no dries, or no tornadoes, or one or all in excess, till at last he comes to the conclusion that the Clerk of the Weather must have mislaid his ledger. Contrary to the popular idea, which has descended to us from the classics, the climate under the Line is not of that torrid heat which a vertical sun suggests; the burning zone of the Old World begins in the northern hemisphere, where the regular rains do not extend, beyond the tenth as far as the twenty-fifth degree. The equatorial climate is essentially temperate: for instance, the heat of Sumatra, lying almost under the Line, rarely exceeds 24° R.= 86° Fahr. In the Gaboon the thermometer ranges from 65° to 90° Fahr., "a degree of heat," says Dr. Ford, "less than in many salubrious localities in other parts of the world."
Upon the Gaboon the wet seasons are synchronous with the vertical suns at the vernal and autumnal equinoxes. "The rainy season of a place within the tropics always begins when the sun has reached the zenith of that place. Then the tradewinds, blowing regularly at other seasons, become gradually weaker, and at length cease and give way to variable winds and calms. The trade-wind no longer brings its regular supply of cooler, drier air; the rising heats and calms favour an ascending current" (in the sea-depths, I may add, as well as on land), "which bears the damp air into the upper regions of the atmosphere, there to be cooled, and to occasion the heavy down-pour of each afternoon. The nights and mornings are for the most part bright and clear. When the sun moves away from the zenith, the trade-winds again begin to be felt, and bring with them the dry season of the year, during which hardly ever a cloud disturbs the serenity of the skies.
"Between the tropical limits and the equator, however, the sun comes twice to the zenith of each place. If now, between the going and coming of the sun, from the Line to its furthest range, a sufficient pause intervenes, or if the sun's temporary distance from the zenith is great enough, the rainy season is divided into two portions, separated by a lesser dry season. Closer to the tropical lines, where the sun remains but once in the zenith, the rainy season is a continuous one."
Such is the theory of the "Allgemeine Erdkunde" (Hahn, Hochstetter and Pokorny, Prague, 1872). An explanation should be added of the reason why the cool wind ceases to blow, at the time when the air, heated and raised by a perpendicular sun, might be expected to cause a greater indraught. We at once, I have said, recognize its correctness at sea. The Gaboon, "in the belt of calms, with rain during the whole year," has two distinctly marked dry seasons, at the vernal and the autumnal equinoxes. The former or early rains (Nchangyá?) are expected to begin in February, with violent tornadoes and storms, especially at the full and change, and to end in April. The heavy downfalls are mostly at night, possibly an effect of the Sierra del Crystal. I found March 28th (1862) very like damp weather at the end of an English May; April 6th was equally exceptional, raining from dawn to evening. During my trip to Sánga-Tánga and back (March 25th to 29th) we had frequent fogs, locally called "smokes," and almost daily tornadoes, sometimes from the south-east, whilst the lightning was dangerous as upon the Western prairies. After an interval of fiery sun, with occasional rain torrents and discharges of electricity, begin the Enomo (Enun?), the "middle" or long dries, which last four months to September. The "Enomo" is the Angolan Cacimbo, meaning cool and cloudy weather, when no umbrella is required, and when the invariably grey sky rarely rains. Travellers are told that June and July are the cream of the year, the healthiest time for seasoned Europeans, and this phantom of a winter renders the climate more supportable to the northern constitution.
During the "middle dries," when the sun, retiring to the summer solstice, is most distant, land winds and sea breezes are strong and regular, and the people suffer severely from cold. In the Gaboon heavy showers sometimes fall, July being the least subject to them, and the fiery sun, when it can disperse the clouds, turns the soil to dust. At the end of September appear the "latter rains," which are the more copious, as they seldom last more than six hours at a time. It is erroneous to assert that "the tract nearest the equator on both sides has the longest rainy season;" the measure chiefly depends upon altitude and other local conditions.
The rainy seasons are healthier for the natives than the cold seasons; and the explorer is often urged to take advantage of them. He must, however, consult local experience. Whilst ascending rivers in November, for instance, he may find the many feet of flood a boon or a bane, and his marching journeys are nearly sure to end in ulcerated feet, as was the case with poor Dr. Livingstone. The rains drench the country till the latter end of December, when the Nángá or "little dries" set in for two months. The latter also are not unbroken by storms and showers, and they end with tornadoes, which this year (1862) have been unusually frequent and violent. Thus we may distribute the twelve months into six of rains, vernal and autumnal, and six of dry weather, æstival and hibernal: the following table will show the sub-sections:—
Early December to early February, the "little dries;" February to early April, the "former," early or spring rains; May to early June, the variable weather; June to early September, the Cacimbo, Enomo, long or middle dries; September to early December, the "latter rains."
Under such media the disease, par excellence, of the Gaboon is the paroxysm which is variously called Coast, African, Guinea, and Bullom fever. Dr. Ford, who has written a useful treatise upon the subject,[7] finds hebdomadal periodicity in the attacks, and lays great stress upon this point of chronothermalism. He recognizes the normal stages, preparatory, invasional, reactionary, and resolutionary. Like Drs. Livingstone and Hutchinson, he holds fever and quinine "incompatibles," and he highly approves of the prophylactic adhibition of chinchona used by the unfortunate Douville in 1828. Experience in his own person and in numerous patients "proves all theoretical objections to the use of six grains an hour, or fifty and sixty grains of quinine in one day or remission to be absolutely imaginary." He is "convinced that it is not a stimulant," and with many apologies he cautiously sanctions alcohol, which should often be the physician's mainstay. As he advocated ten-grain doses of calomel by way of preliminary cathartic, the American missionaries stationed on the River have adopted a treatment still more "severe"—quinine till deafness ensues, and half a handful of mercury, often continued till a passage opens through the palate, placing mouth and nose in directer communication. Dr. Ford also recommends during the invasion or period of chills external friction of mustard or of fresh red pepper either in tincture or in powder, a good alleviator always procurable; and the internal use of pepper-tea, to bring on the stages of reaction and resolution. Few will agree with him that gruels and farinaceous articles are advisable during intermissions, when the patient craves for port, essence of beef, and consomme; nor can we readily admit the dictum that in the tropics "the most wholesome diet, without doubt, is chiefly vegetable." Despite Jacquemont and all the rice-eaters, I cry beef and beer for ever and everywhere! Many can testify personally to the value of the unofficinal prescription which he offers in cases of severe lichen (prickly heat), leading to impetigo. It is as follows, and it is valuable:—
Cold cream. . . . . . . . . . 3j. Glycerine . . . . . . . . . . 3j. Chloroform . . . . . . . . .3ij. Oil of bitter almonds . . gtt. x.