|
|
Alum
Historical and geographical information
|
|
Alum
The Jurassic shales and sandstone of
Cliff Ridge and Gribdale contain bands of ironstone,
jet and alum, as well as whinstone.
The oldest of these industries was alum.
This mineral had been used since ancient times for many purposes including
medicinal (as cure for haemorrhages, nits and dandruff, and other ailments).
Its main uses since the middle gages were to increase the suppleness and
durability of leather and in the textile industry as a mordant to make
vegetable dyes fast.
Alum Shale is found in beds immediately
beneath the sandstone of the North York Moors.
Alum mining has been a North Yorkshire
industry since alum was first discovered in the hills around Guisborough by Sir
Thomas Chaloner the younger in the 1590s. At the end of the 16th century Thomas
Chaloner visited alum works in the Papal States where he observed that the rock
being processed was similar to that under his Guisborough estate. At that time
alum was important for medicinal uses, in curing leather and for fixing dyed
cloths and the Papal States and Spain maintained monopolies on its production
and sale. Chaloner secretly brought workmen to develop the industry in
Yorkshire, and alum was produced near Sandsend Ness 5 km from Whitby in the
reign of James I. Once the industry was established, imports were banned and
although the methods in its production were laborious, England became
self-sufficient. Whitby grew significantly as a port as a result of the alum
trade and by importing coal from the Durham coalfield to process it.
In 1610 James I made Alum production a
monopoly of the Crown.
In 1616 Alum production began at Selby
Hagg, near Hagg Farm, Skelton around this date. It is said that ships anchored
off Saltburn to transport the finished product. They brought with them casks of
urine, which was mixed with the liquid that had been obtained from the calcined
shale. It is not presently known where this process was carried out initially,
as later in the century it was done in an Alum House sited near Cat Nab in
Saltburn. The shale liquid ran from Selby Hagg by gravity down a trough
that followed the course of Millholme Beck.
From the early seventeenth century until
the 1860s it was extensively mined at Guisborough and along the East Cleveland
coast. The actual extraction of alum from shale was a long and expensive
process and it took an average of 50 tons of shale to produce one ton of alum.
In the 16th-century alum was essential in the textile industry
as a fixative for dyes. Initially imported from Italy where there was a
Papal monopoly on the industry, the supply to Great Britain was cut off during
the Reformation. In response to this need Thomas Challoner set up Britains
first Alum works in Guisborough. He recognised that the fossils found around
the Yorkshire coast were similar to those found in the Alum quarries in Europe.
As the industry grew, sites along the coast were favoured as access to the
shales and subsequent transportation was much easier.
Alum mine, Cleveland
In
the mid eighteenth century the price of alum was particularly high and reached
a peak of £24 per ton in 1765. It therefore became commercially viable to mine
in places where this had not been the case previously. Several new mines were
therefore opened including one east of Ayton at Ayton Bank, just north of
Hunter’s Scar.
Cockshaw
Alum Works at Gribdale quarried and processed the
shale to produce alum crystals in the eighteenth century.
At the peak of alum production the industry required 200
tonnes of urine every year, equivalent to the produce of 1,000 people. The
demand was such that it was imported from London and Newcastle, buckets were
left on street corners for collection and reportedly public toilets were built
in Hull in order to supply the alum works. This unsavoury liquor was left until
the alum crystals settled out, ready to be removed. An intriguing method was
employed to judge when the optimum amount of alum had been extracted from the
liquor when it was ready an egg could be floated in the solution.
The last Alum works on the Yorkshire Coast closed in 1871. This was due to the
invention of manufacturing synthetic alum in 1855, then subsequently the
creation of aniline dyes which contained their own fixative.
There are many sites
along the Yorkshire Coast which bear evidence of the alum industry. These
include Loftus Alum Quarries where the cliff profile
is drastically changed by extraction and huge shale tips remain. Further South
are the Ravenscar Alum Works, which are well preserved and enable visitors to
visualise the processes which took place
Alum and Skelton
In the Skelton
area Alum production began from about 1603. The first profitable site in
Yorkshire was opened in 1603 at Spring Bank, Slapewath,
which was then part of Skelton. This was the project of John Atherton, joint
owner by marriage of a third part of the Skelton Estate.
Britain at this time was an Agricultural
nation and Wool was its chief export.
Alum was used in the dyeing process as
the setting agent and was also needed in the tanning of hides. It was therefore
a highly valued product, which up to this time had been imported. Rich rewards
seemed to beckon those who could create a home industry. The process was
complex. The alum bearing rock was quarried, broken up and ‘calcined’ or built
into large clamps with alternating layers of wood and these piles would be
ignited and a controlled burning would last for weeks. It needed many tons of
shale to produce 1 ton of alum. The
burnt, ‘calcined’, shale was then steeped in water-filled stone troughs until a
certain specific gravity had been reached (tested for, the story goes, by
floating an egg in the liquid). The liquid was then run off and boiled in large
pans heated by coal for 24 hours and mixed with an alkali, obtained from urine
or seaweed.
Thomas Chaloner of Guisborough is reputed
to have sold his personal urine for one penny a Firkin, which was about 8
gallons. How often he earned or spent a penny or earned one is not recorded.
History shows that we have had many odd
names for imperial measures, pecks and gills etc. A ‘Firkin a Fortnight’ for
pee.
Next the mixture was transferred to
small coolers to crystallize, the resulting crystals of alum being further
boiled and condensed to get rid of impurities. Many legends survive, but it is
not known how this long and involved chemical process was discovered in these
times, when people believed in alchemy and the modern science of Chemistry was
a mystery.
It is reported that the workers suffered
terrible conditions – the heaps of shale gave off poisonous sulphurous fumes
and at times their wages of 6 pence a day were often withheld or ‘given in half
rotten meat and corn.’
The alum workers were described at one
point as: ‘poor snakes, tattered and naked, ready to starve for want of food
and clothes.’
Other Alum mines were eventually opened
by the Skelton Estate, notably at Coombe Bank, Boosbeck
and Selby Hagg between Skelton and Brotton and were worked on and off during
the next two centuries. The Selby Hagg works were located to the east of Hagg
Farm, near Skelton-in-Cleveland, and would seem to have had three distinct
periods of operation.
During the first of these, from about
1617 to 1643, the Alum house may have been located within the quarry.
The second phase ran from 1670 to 1685,
and the third from 1765 to 1775. The alum houses for these latter two phases
were located at Saltburn.
Most successful were the ones on the
coast which did not have the cost of transporting fuel and the finished product
for shipment.
The Alum workings at Hummersea,
Loftus were worked well into the 19th Century.
Major Robert Bell Turton
of Kildale Hall, N Yorks The Alum Farm, 1937: "There was a house at Spring Bank, near Mygrave [now Margrove Park]
erected, but not completed for the manufacture of Alum. On the 15th November
1603 an agreement was made between John Atherton and Katherine his wife of the
one part and Mr Leycolt of the other, under which the
Athertons were, at their own cost, to complete the
house and furnish it with the necessary appliances, namely, four Furnaces and
four pans of lead and iron for boiling Alum, Coolers of lead for congealing ,
and convenient Cisterns of lead for keeping and saving the "mothers"
or strong liquors of alum and Copperas [green vitriol or Iron Sulphate]. They
were also to set up a lead-finer with furnace, a balnium
for trial of the earth for alum and copperas, pits, pipes, vessels for draining
the earth and making liquors and all other necessary implements."