Alum, Henry and

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Alum, Henry and the Pope
Name
A HenryTudor.co.uk Production
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Wool has been a cheap cloth throughout history
and only when is was brightly coloured did it
become a desired product. The trouble is that if
fibres of cloth was dipped into vegetable dye it
ran out again when it was wet. What was needed
was a chemical that etched the colour into the
fibres by removing the resistance to the dye.
That chemical was Alum. After dipping the fibres
into Alum, a dye could sink in deeper into the
fibres and thus stay there even when wet. The
discovery was by the Romans who had used Alum to
soften their leather, Fireproofing their uniforms
and even for a skin healer. They found it lying
on their land in Italy and it soon became one of
the most valuable Technologies they possessed.
In the fifteenth century the whole alum industry
came under the control of the Vatican (The Holy
Roman Empire). This meant that when King Henry
VIII had a row with the Pope because he wanted to
divorce Katherine of Aragon, the supplies of alum
to England were cut off. King Henry instigated
the search across Britain for our own sources of
Alum bearing rocks. Thanks to the vegetation
giving it away and the coastal erosion show the
searchers where it was, Alum bearing shale was
soon found in North Yorkshire. Here workers built
a mountain of shale and set fire to it to
release the Alum fro its ore, the fire was kept
going for 9 months until the shale was ready.
The process of using another substance to break
down the materials resistance before the process
begins is called a Mordant, it was the Aluminium
in the Alum that did this.
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This is a strange tale of power, vanity, great
wealth, industry and ingenuity. It started with
the Romans desire for colourful clothes and
spread about the developing world as they invaded
lands.
Visit Ravenscar today and what you will see is a
very beautiful stretch of the North Yorkshire
coast, where the steep, eroding cliffs look out
over the windswept North Sea. How could such a
place be the birthplace of the British Chemical
Industry? Nowadays it doesnt even look much like
the industrial wasteland it had actually become.
This land and its people became a great
international business that involved Henry VIII,
tonnes of seaweed, and vast quantities of stale
human urine. Oh Yuk! It had a commodity savoured
by the wealthy, the market broken away from the
Pope and set up in competition to supply the need
to colour cloth. What was the ingredient that was
so powerful, so valuable and so rare until Henry
demanded his own supply?
Alum
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As you walk into Ravenscar on your left you will
see an old workings next to an old quarry. These
are the end products of centuries of Alum
production. The site had its own port where
seaweed, Urine was landed.
Cargoes from the sea were taken up the steep
cliffs on a stone causeway by teams of pack
horses or in wagons on an inclined railway which
was powered by a Steam Engine in a winding shed
at the top of the cliff. Technology came and
went.
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This is what it was all about, Alum Flour a
fixative for dye onto fibres of cloth.
The National Trust Visitors centre at Ravenscar
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Just look at the layers of stone, so many colours
indicating metals in their Ore state.
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Britain did have a problem! In Italy and Greece
they had Volcanic land where the heating of the
shale had been done for them. The Romans just
mined it ready for processing, we couldnt, we
had to make it first by heating it up for up to
year until the shale turned red. The two quarries
at Ravenscar yielded more than a million tons of
shale, dividing this by 100, this meant that
10,000 tons of Alum were made there. From the
16th century the industry grew until it employed
hundreds of people by the 18th Century. All
summer, the pick-men hacked lumps of grey shale
from the cliff with pickaxes. Barrowmen wheeled
it down steep and narrow paths to the bottom, and
built huge bonfires called clamps, 10 or 20
metres high. They put brushwood at the bottom to
start the fire, and then piled shale on top. The
fires smouldered away for 9 to 12 months and the
rain on the outside kept them from getting too
hot. After several months in the fire, the whole
rock turned red. Then the liquor-men tipped the
red rock into big pits of water to extract
Aluminium Sulphate. The used red rock was hauled
out of the pits by the pitmen, and tipped out to
make great man-made hills, which are still there,
covered with yellow-flowered, prickly gorse. The
aluminium sulphate solution was channelled into
cut-stone gullies, and ran down the hill into the
alum works on the top of the cliff, collected in
a tank, and when each batch was ready it was run
down into the treatment works, boiled, and
allowed to settle.
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Thanks to the National Trusts brochure of the
Peak Alum works at Ravenscar, North Yorkshire.
Alum has been in use for centuries.
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It took 100 Tons of Shale from the quarry to
produce 1 Ton of Alum.
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Why did they need Seaweed and Urine?
With the Aluminium Sulphate, which has been made,
they added Potassium and Ammonia. Seaweed when
toasted produces Potassium, after using up all
their own, the seaweed had to be shipped in from
far and wide. Next they needed Ammonia, and for
that they used old human urine. One adult
produces approxiamately 1.5 Litres of urine every
day. To begin with they collected it locally
there were barrels everywhere in the area, and
all the people were invited to contribute. But
demand grew larger and Urine had to be shipped in
from the big cities. In the heyday of the
industry used about 200 tons a year, which would
have meant the urine from about 1000 people. The
smell must have been quite obnoxious! As it gets
older, urine becomes richer in ammonia because of
biochemical decomposition of the urea. It became
known that the urine from Poor working people
was much better than the urine from the wealthy,
because they did not drink so much strong
alcoholic drinks!
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So what happened to the Alum industry?
In 1856, a man called William Perkins invented
synthetic dyes, not using vegetation and not
needing a fixing agent like Alum. So the industry
died away for a while.
Nowadays Alum is used in the pulp papermaking
industry and for water and wastewater treatment,
Other uses are