Forest Flora of Portuguese East Africa. 
I 
136 
as to drop off then the collector wets his thumb in his mouth, passes it over the wound, collecting on it all the latex available at the moment, and immediately smears this on 
his forearm or chest, or elsewhere on his body, one who is climbing and collecting sometimes coming to the ground covered all over with coagulated latex ready to roll off. The 
milk is white at first but changes to amber-colour as it dries ; as it is never collected in vessels there is little opportunity for sticks or dirt being included, but as Mr. Johnson 
says, “The wily native at one time adulterated his rubber by winding it around pieces of stone, lead, dirt, &c., but this practice is now abolished, as small balls or spindles are 
demanded which are cut open on receipt. This process likewise expedites the drying of the rubber, which is at present effected in open sheds without the aid of artificial heat. 
The rubber is packed for export in sacks which contain about no pounds.” He further states: — “It possesses excellent physical properties, and the following analysis, made of 
fair samples at the Imperial Institute, London, demonstrates both its high caoutchouc content and freedom from deleterious impurities : — 
Moisture 
Sample as Received. 
Per Cent. 
S'° 
Composition 0: 
Dry Rubber. 
Per Cent. 
Caoutchouc 
85-6 
90 - i 
Resin 
5'5 
57 
Proteids - 
I "3 
i '3 
Insoluble 
27 
28 
Ash 
o'46 
0*48 
The rubber, when properly prepared is always in good demand, and realises prices only slightly inferior to ‘ Fine Para 
The above analysis is supported by the following, prepared by the Director of the Imperial Institute on two samples submitted by me in 1904, prepared from Landolphia 
vines in Natal Maputa, just across the boundary of this Province. 
As received. 
Calculated for 
Dry Material. 
As received. 
Calculated for 
Dry Material. 
Per Cent. 
Per Cent. 
Per Cent. 
Per Cent. 
Moisture 
7 7 
— 
9* 
— 
Caoutchouc - 
So 1 1 
86 8 
757 
833 
Resin 
69 
7 '5 
103 
11 ‘3 
Dirt 
53 
5 7 
4'9 
5 '4 
Ash, included in Dirt 
031 
°‘33 
o ‘37 
o‘4o 
Professor Dunstan remarks:— “ Both had evidently been carefully prepared, and their physical characters were exceedingly good. In composition they compare very 
favourably with other samples of rubber derived from Landolphia Kirkii which have recently been examined in the Scientific and Technical Department of the Imperial Institute. 
The rubbers were submitted for valuation to brokers, who report that consignments represented by those specimens would command a very ready sale, and would probably realise 
as much as 4s. per lb. in the London market at the present time.” 
Mr. Johnson touches another important point as follows: — “Experiments have been conducted by the writer with the view of improving the quality and keeping 
properties of the rubber by exposing it to the smoke given off fires fed with wood. Samples of rubber prepared in this manner and similar ones taken from the same collection, 
but dried by the ordinary method, were submitted for valuation to London rubber brokers. The smoked samples were rated at 4s. to 4s. id. per lb., and the unsmoked samples 
at 3s. 1 id. to 4s. per lb., when ‘ Fine Para’ was selling at 4s. 2d. per lb. In their report upon this subject the brokers state that the smoked samples were slightly improved both 
in quality and appearance by the process, as it gave them a brighter look and appeared to increase their elasticity. There is always an abundance of wood-fuel available in the 
rubber districts, and, as the period of drying is considerably curtailed when the smoking method is adopted, it is considered that it might be generally employed with 
advantage.” 
