British Empire Article

Courtesy of OSPA

by John Henry Harris
Reading Anthony Kirk-Greene's absorbing On Crown Service, I was delighted to find myself as a statistic on two pages. One was on page 26, Table 2.3 where it was revealed that in 1935 there were seven recruits for Survey and Geological. I was one of them. The other was on page 40 where (para 3) "... the loss of Malaya as a major source of rubber and tin meant that in many other colonies, particularly in Africa, the colonial administration was obliged ... to step up the production of these vital commodities". There I was again.

When the Second World War broke out I was not allowed to enlist and was commissioned to increase the production of gold and other minerals for the war effort and it fell to me to help in the production of rubber and sisal and in other activities unexpectedly related to mineralogical expertise


It so happened that when Tanganyika was a German colony (German East Africa, 1891-1918) an attempt had been made to start rubber planting. Lacking the climate and soil conditions of Malaya the regular rubber tree (Para) was not a success, but the knobbly-barked Ceara proved hardy in conditions varying seasonally from moist to semi-arid and was a useful source of latex. An extensive stand had been planted south of Morogoro. By 1941 it had all but disappeared in the encroaching bush. Two rubber planters who had escaped from Malaya were brought in to evaluate the trees and they decided that it might be worth attempting production.

A War Effort in Tanganyika
Ceara Rubber Tree
The undergrowth was cleared and tapping was tried. The first set of tapping knives was produced by the Tanganyika Railways workshops in Dar es Salaam from old railway wagon springs. The special hook-shaped knife is sharpened on both leading and trailing edges and requires continuous honing in use. In Malaya they used a Water of Ayr stone which is a natural fine-grained abrasive, cut into slips four inches long by an inch or so wide, tapered from one long side to the other and used wet. A plea came up to the Geological Survey - could we produce such a honing stone? Yes, we said, but we have no means of cutting it into such slips.

However, it occurred to me that we could fabricate a suitable hone by incorporating grains of abrasive into a ceramic body. Rapid experimentation produce a hone containing corundum as the abrasive bound into a ceramic composed of local kaolin, silt and soda and fired in our own kiln. It proved suitable and within a month we were in production at the rate of hundreds a week. We mined the corundum (which is the hardest natural stone next to diamond and is also the mineralogical constituent of rubies and sapphires) in the Central Province not far from our headquarters office at Dodoma and crushed and graded it in our laboratories. The kaolin we mined at Malangali 220 miles away. It was an impure variety on which we had been experimenting pre-war. Its impurities played a part in the formation of our unique ceramic, which was also modified by the addition of the local silt dug out of our water-supply reservoir and of soda from Magadi in Kenya.

All these ingredients were mixed by hand with added water into a dough-like constituency, spatula-fed into wooden moulds to the exact required shape and racked to air-dry. The moulding and racking systems were worked out by my former chief, Frank Oates. I did design an extrusion press and had it made in the Railway workshops but the hand-made system got under way faster, using a crew of ten in a rapidly built extension to our laboratories. We even introduced a hole in the corner of the hone so that the tappers could string it on a cord around their necks. This greatly suited the tribe of Wagogo from the Central Province who proved the most expert rubber-tappers. And so we enabled the production of rubber to get going.

When it became known that we were producing abrasives new calls arose. The first was for the type of sharpening stone used by carpenters for plane blades and chisels which is relatively coarse on one side and smooth on the other. The problem arose of moulding and firing these two disparate masses together without distortion but we solved that. Several hundred were made and distributed widely, even to Uganda and Kenya.


A War Effort in Tanganyika
Drying Sisal
The next episode averted a disaster. The loss of Manila to the enemy left sisal as the only fibre available on a large scale for ropes and cordage, in those days before the advent of polypropylene. The prospect of HM ships breaking loose from their moorings as the last rope parted was too awful to envisage, so the great sisal estates in Tanganyika had to maintain and increase production. Critical to the process is the decorticator, a vast machine which separates the pulp from the sisal leaf leaving the fibres long, clean and unbroken. To keep the machine running efficiently in this delicate separation the beaters on its huge drums have to be honed constantly to fine limits. This is done by an abrasive cup-wheel mounted over the drum and mechanically traversed across the beaters at right angles to their travel and at a rotational speed of 10,000 revolutions per minute.

The industry then broke its last cup-wheel. The prospect of war-time imports was remote so I was set to making cup-wheels. This time, obviously, accurate balance was a priority. Using the facilities of our own workshop (which was designed for servicing heavy drilling equipment) our African foreman turned out from wood the circular forms which were needed for pressing out the cup shapes, which then required special firing procedures to avert distortion. We made the metal bosses of the wheels from the lead of old car batteries and trued them up on the lathe with a tool made of corundum. I took the first one personally to the sisal estate which had approached us and saw that it fitted accurately on to the spindle of the high-speed electric motor. Then I stood back, heart in mouth, as it spun into action, safely, accurately and efficiently. More and more of these wheels were made as requests came in. I think we saved the industry from shut down.


The next episode was directed towards the acceleration of the production of beef for the armed forces. This demanded the extension of herds of cattle, which in turn demanded control of tsetse fly. This involved cutting swathes through the forests which required regiments of men with pangas and the pangas required sharpening. Scythe stones were the traditional tools, but a supply from home was again out of the question so I started production of sharpening sticks made from my abrasive formula. This time my hand-operated extrusion machine came into use, with a die made from Kisii stone from Kenya, hardened in the kiln to resist the abrasion. The sticks were extruded on to boards provided with grooves on to which the sticks slid and were cut off to size. To facilitate the sliding action the grooves were lubricated with graphite which we also had to mine from local deposits and process in the laboratory. Several thousand of these sticks were fired in our kiln and distributed to the teams in the field. (Some found their way on to the dining tables of HMOCS colleagues for use as sharpeners for their carving knives).


In between we had a little go at razor-blade sharpeners but the final effort arose from a request from the military for a million trouser buttons. I had already succeeded in making ceramic buttons from Kisii stone so I decided that I could go into production if I could use the pill-press which the Medicals were using to produce anti-malarials from our local growths of cinchona. Our workshop made the dies and we were ready to go when the news arrived that the buttons were no longer required.

They were going to use zip-fasteners.

Colonial Era Map
Morogoro Map, 1958
Colony Profile
Originally Published
OSPA Journal 79: April 2000