Angola and the River Congo, vol. 2

by Joachim John Monteiro

About twenty or twenty-four miles to the south of Benguella is situated the district of Dombe Grande. There is here a large native population on the southern bank of the River San Francisco or Capororo, governed by a Portuguese “chefe.” The road to it from Benguella passes over slightly undulating ground, but very arid in character, alternately sandy, dusty, and of gypsum rock.

About half way, at a place called Quipupa, there is a small spring of ferruginous water, which is the halting-place of the natives who frequent the road to and from Dombe Grande. It is a wonderful relief from the desert road to arrive at the River San Francisco, and see stretched for miles the beautiful green expanse of Dombe Grande. The river is perfectly dry for one half of the year, and is then a broad band of pure, dazzling, white sand, but the land near it is extremely fertile, and very large quantities of mandioca and beans are grown. The mandioca is made into “farinha” or meal, and thousands of bushels are sent by road to Benguella, or to Cuio Bay for shipment. The sand of the river will even grow splendid crops of this root as soon as the water dries up.

Towards the sea the valley of this river is very broad; and it is here that the extensive cotton plantations, to which I have already referred, exist. This part of the country is called “Luache,” and in it there are some very curious lagoons and quicksands. One of these lagoons is extremely deep. A Portuguese told me he had tried to sound it, but had failed to touch the bottom.

At another place the road for some considerable distance is over a narrow path composed of the roots of large sedge-like plants interwoven and grown together, and yielding under every step. The Mundombes take their cattle over this path, but should one walk away from it at the side, it sinks immediately in the black mud, and is seen no more.

There is a great deal of pure sulphur in the gypsum hills on the northern bank of the river at Dombe Grande, and going across them once, I came to a small eminence that seemed to be all sulphur, and with a knife, a stick, and a few wedges that I cut, I managed to detach a solid block of sulphur of about thirty pounds in weight.

At Luache the trees and bushes are covered with a vast quantity of a curious leafless parasite. This is a creeper, which grows luxuriantly in great masses of long, thin, green strings or stems, sometimes completely covering the tree. These are full of tasteless mucilage when fresh, and are employed in decoction as an emulcent in coughs and colds. When dry these wire-like stems become black and hard, and give the trees a very mournful and dismal appearance. This plant is a species of Cassytha (C. Guineensis?) and although excessively abundant in the province of Benguella, becomes scarce to the north.

About nine miles south of Dombe Grande is the little bay of Cuio, in 13° S. lat., to the interior of which I explored a copper deposit in 1861-1863. This deposit was situated four miles from the bay in the bottom of a small circular depression or valley in the gneiss rock of the country. It was evident that the copper ore had been brought from a distance by the action of water, and precipitated in the bottom of this cup or basin.

The lower part consisted of a bed of the rare indigo-blue sulphide intimately mixed together with quartz gravel or sand, the blue sulphide forming the matrix of this curious conglomerate, in which were also found large, rounded, smooth, water-worn masses of hard compact gneiss. This bed alone yielded nearly 1000 tons. Another 1000 or 1200 tons were obtained from a higher part of the valley, and consisted of a hard amorphous mixture of sulphide and blue and green carbonate, the latter apparently due to the surface decomposition of the former. Some small masses of this copper ore contained silver, from a mere trace to over 100 ounces in the ton. In one place I found a few tons of lead ore, earthy carbonate and sulphate, with only a trace left of the galena that had no doubt supplied the two by its decomposition. Specimens of these ores were exhibited in the London International Exhibition of 1862, and were awarded honourable mention.

I was the first in Africa to make plaster of Paris from the gypsum rock of the country, and to apply it to cover walls of houses, for flooring, and even for roofing. I had to build stores at Cuio mines, and houses for twenty-two white miners, and as there was no grass or other material fit to roof them with, I put a layer of plaster of Paris, about an inch and a half thick, on a framework of palm-leaf stems, and it withstood the rain admirably. It is magnificent material for flooring in that country, absorbing moisture and preventing the white ant from getting through. The Portuguese soon after made great use of this material, which had existed in inexhaustible quantities unknown to them for so many years.

The road from Dombe Grande to Cuio passes through some deep perpendicular ravines cut in solid gypsum rock by the action of the waters, and in other parts of Benguella it is equally abundant. It requires no kiln for burning: it is sufficient to make a pile of small pieces of the rock with any kind of fuel or brushwood at hand to burn it into proper plaster of Paris; in fact, if burnt in a kiln, or exposed to too great a degree of heat, it will not set afterwards when mixed with water.