OcTOIiER I, 1904.] 



THE INDIA RUBBER V/ORLD 



RUBBER COAGULATING METHODS IN CENTRAL AFRICA. 



By Gitstave van den Kerckhove {Brussels). 



OF all rubber producing countries the Congo Free State 

 without doubt offers the greatest variety in the way of 

 coagulating latex. How many native systems are em- 

 ployed for coagulating! he /ii/f.r of the Landolphia vine, 

 for instance, it would be hard to say, though at least six or 

 seven general methods are in use. But every tribe, even every 

 man of a tribe, has his own ideas about the preparation of rub- 

 ber. This is the reason why every parcel and even every piece 

 of a parcel of Congo rubber shows some difTerence from every 

 other piece and parcel. For example, take a parcel of a few 

 tons of white rubber ball (" Equateur"), and of the 50,000 to 

 60.000 pieces (mostly balls) of 

 that parcel, no two are alike ; 

 some are small, some large, 

 others adulterated, and so on. 

 They show the character of 

 the men who have prepared 

 them, and a keen observer 

 could even estimate approxi- 

 mately the age of the men by 

 the size of the pieces. I do 

 not believe that civilization in 

 Central Africa has improved 

 the quality of rubber, except 

 in checking adulteration. It 

 is well known that a savage 

 negro from the interior may 

 make better rubber than the 

 coast native who has been " in 

 touch with civilization," and 

 this is not only so in the Con- 

 go, but in every African rub- 

 ber producing district. 



Of the different methods of 

 coagulation which I shall now 

 endeavor to describe, only one 

 has been suggested or discov- 

 ered by the white man. Not 

 only is there a great variety in 

 the way the native coagulates 

 the latex, but in the different 

 forms he gives to the rubber, 

 viz.: Balls, cakes, slabs, brace- 

 lets, strips, cubes (thimbles), 

 and so on. This, of course, is 

 merely a question of fancy. 

 Most of the Congo rubber is 

 taken from the Landolphia tapping 'lan 



vine, and the first method of curing the rubber — here men- 

 tioned because it is the oldest — is that known among the 

 natives as the calabash system. 



The native collects the milk in a calabash, in which a hole 

 has been madeat the bottom, some water being mixed with the 

 latex. After 12 to 2ohoursof rest, the latex, which has already 

 reached a state of consistency, floats, and the water is poured 

 out by opening the hole. The latex alone remains now in the 

 calabash for a certain time, and is given whatever size or form 

 the native fancies, when it Is left to dry naturally, or sometimes 



is slightly smoked. This method, in vogue among the natives 

 of the Aruwimi, Itimbiri, Mongala, Kasai, and Kwilu districts, 

 is fairly good, though the rubber has a tendency to ferment. 



In some regions farther north the method employed is still 

 more primitive. The latex is collected with a leaf and poured 

 into any sort of receptacle — calabash, wooden jar, or iron pot - 

 and is left to coagulate naturally, with the result that most of 

 the rubber collected in this way is fermented, and even rotten. 

 It is singular that such curing gives rubber of good elastic qual- 

 ities, but the smell of the stuff is simply horrible. 

 The Kasai district natives use two different methods. For 



instance, after the vine has 

 been tapped they cover their 

 bodies with the latex a.n6 re- 

 turn home. The water con- 

 tained in the latex having by 

 that time evaporated, the 

 latex, which has then the ap- 

 pearance of rubber, is taken 

 off and turned by hand into 

 balls or twists. This method 

 is also used by other natives 

 of the upper Congo. Here is 

 another method of the Kasai 

 natives: The vine is bled and 

 the next morning the latex, 

 having become slightly coagu- 

 lated in the open air along the 

 branch of the vine, they take 

 the rubber, winding it round 

 their fingers or a small stick, 

 making twists of ten balls per 

 twist. This rubber, known 

 under the name of " prime red 

 Kasai." is one of the best Afri- 

 can grades. The "prime black 

 Kasai" is obtained by the 

 boiling and smoking process, 

 of which I shall say a few 

 words further. 



Now I come to a most im- 

 portant question about curing 

 the latex of Landolphia— Vnt 

 process of coagulation with 

 the Bosanga juice. The Costus 

 afer (the " Bosanga " plant) 

 has more the appearance of a 

 DOLPHiA- VINES. reed than a tree. The coagu- 



lating properties of its juice were discovered a few years ago in 

 the Lopori district, and this method gives wonderful results, 

 although it is Aery simple. A small percentage of Bosanga 

 juice is mixed with the latex and, with his finger or a stick, the 

 man stirs the liquid, the coagulation taking place almost in- 

 stantly. After this, the latex, which now is a thick mass, is 

 shaped into balls and left to dry in the shade or stored in a 

 bungalow. It takes as a rule six to eight weeks for the rubber 

 to dry enough for shipment to Europe. I think it most im- 

 portant to mention that the Bosanga juice coagulates latex 



