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.
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.
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.