To Upgang--Enter Cleveland--East Row--The first Alum-Maker--
Sandsend--Alum-Works--The huge Gap--Hewing the Alum Shale--
Limestone Nodules: Mulgrave Cement--Swarms of Fossils--Burning
the Shale--Volcanic Phenomena--From Fire to Water--The Cisterns
--Soaking and Pumping--The evaporating Pans--The Crystallizing
Process--The Roching Casks--Brilliant Crystals--A Chemical
Triumph--Rough Epsoms.
It was yet early the next morning when I descended from the high road to
the shore at Upgang, about two miles from Whitby. Here we approach a
region of manufacturing industry. Wagons pass laden with Mulgrave
cement, with big, white lumps of alum, with sulphate of magnesia; the
kilns are not far off, and the alum-works at Sandsend are in sight,
backed by the wooded heights of Mulgrave Park, the seat of the Marquis
of Normanby. Another half-hour, and crossing a beck which descends from
those heights, we enter Cleveland, of which the North Riding is made to
say,
"----If she were not here confined thus in me,
A shire even of herself might well be said to be."
Hereabouts, in the olden time, stood a temple dedicated to Thor, and the
place was called Thordisa--a name for which the present East Row is a
poor exchange. The alteration, so it is said, was made by the workmen on
the commencement of the alum manufacture in 1620. The works, now grimy
with smoke, are built between the hill-foot and the sea, a short
distance beyond the beck.
The story runs that the manufacture of alum was introduced into
Yorkshire early in the seventeenth century by Sir Thomas Chaloner, who
had travelled in Italy, and there seen the rock-beds from which the
Italians extracted alum. Riding one day in the neighbourhood of
Guisborough, he noticed that the foliage of the trees resembled in
colour that of the leaves in the alum districts abroad; and afterwards
he commenced an alum-work in the hills near that town, sanctioned by a
patent from Charles I. One account says that he smuggled over from the
Papal States, concealed in casks, workmen who were acquainted with the
manufacture, and was excommunicated by the Pope for this daring breach
of his own monopoly. The Sandsend works were established a few years
later. Subsequently certain courtiers prevailed on the king to break
faith with Sir Thomas, and to give one-half of the patent to a rival,
which so exasperated the knight that he became a Roundhead, and one of
the most relentless foes of the king. A great monopoly of the alum-works
was attempted towards the end of the last century by Sir George
Colebroke, who, being an East India director, got the name of Shah
Allum. His attempt failed.
My request for permission to view the works was freely granted, and I
here repeat my acknowledgments for the favour. The foreman, I was told,
took but little pains with visitors who came, and said, "Dear me! How
very curious!" and yawned, and wanted to go away at the end of ten
minutes; but for any one in earnest to see the operations from beginning
to end, he would spare no trouble. Just the very man for me I thought;
so leaving my knapsack at the office, I followed the boy who was sent to
show me the way to the mine. Up the hill, and across fields for about
half a mile, brought us to the edge of a huge gap, which at first sight
might have been taken for a stone quarry partially changed into the
crater of a volcano. At one side clouds of white sulphureous smoke were
rising; within lay great heaps resembling brick rubbish; and heaps of
shale, and piles of stony balls, and stacks of brushwood; and while one
set of men were busily hacking and hewing the great inner walls, others
were loading and hauling off the tramway wagons, others pumping, or
going to and fro with wheelbarrows.
There was no proper descent from the side to which we came, and to
scramble down three or four great steps, each of twenty feet, with
perpendicular fronts, was not easy. However, at last I was able to
present to the foreman the scrap of paper which I had brought from the
office, and to feel sure that such an honest countenance and bright eye
as his betokened a willing temper. Nor was I disappointed, for he at
once expressed himself ready to show and explain everything that I might
wish to see.
"Let us begin at the beginning," I said; and he led me to the cliff,
where the diggers were at work. The formation reminded me of what I had
seen in the quarries at Portland: first a layer of earth, then a hard,
worthless kind of stone, named the 'cap' by the miners; next a deposit
of marlstone and 'doggerhead,' making altogether a thickness of about
fifty feet; and below this comes the great bed of upper lias, one
hundred and fifty feet thick; and this lias is the alum shale. Where
freshly exposed, its appearance may be likened to slate soaked in
grease: it has a greasy or soapy feel between the fingers, but as it
oxidises rapidly on exposure to the air, the general colour of the cliff
is brown. Here the shale is not worked below seventy-five feet; for
every fathom below that becomes more and more bituminous, and more
liable to vitrify when burnt, and will not yield alum. At some works,
however, the excavation is continued down to ninety feet. Embedded in
the shale, most abundant in the upper twenty-five feet, the workmen find
nodules of limestone, the piles of balls I had noticed from above, about
the size of a cricket-ball; and of these the well-known Mulgrave cement
is made. The Marquis, to whom all the land hereabouts belongs, requires
that his lessees shall sell to him all the limestone nodules they find.
The supply is not small, judging from the great heap which I saw thrown
aside in readiness for carting away. Alum shale prevails in the cliffs
for twenty-seven miles along the coast of Yorkshire, in which are found
one hundred and fifty kinds of ammonites.
Besides balls of limestone, the shale abounds in fossils. It was in
this--the lias--that nearly all the specimens, including the gigantic
reptiles of the ancient world which we saw in the Museum at Whitby were
found. Every stroke of the pick brings them out; and as the shale is
soft and easily worked, they are separated without difficulty. You might
collect a cartload in half a day. For a few minutes I felt somewhat like
a schoolboy in an orchard, and filled my pockets eagerly with the best
that came in my way. But ammonites and mussels, when turned to stone,
are very heavy, and before the day was over I had to lighten my load:
some I placed where passers-by could see them; then I gave some away at
houses by the road, till not more than six remained for a corner of my
knapsack. And these were quite enough, considering that I had yet to
walk nearly three hundred miles.
After the digging comes the burning. A layer of brushwood is made ready
on the ground, and upon this the shale is heaped to the height of forty
or fifty feet until a respectable little mountain is formed, comprising
three thousand tons, or more. The rear of the mass rests against the
precipice, and from narrow ledges and projections in this the men tilt
their barrow-loads as the elevation increases. The fire, meanwhile,
creeps about below, and soon the heap begins to smoke, sending out white
sulphureous fumes in clouds that give it the appearance of a volcano.
Such a heap was smouldering and smoking at the mouth of the great
excavation, the sulphate of iron, giving off its acid to the clay,
converting it thereby into sulphate of alumina. All round the base, and
for a few feet upwards, the fire had done its work, and the mass was
cooling; but above the creeping glow was still active. The colour is
changed by the burning from brown to light reddish yellow, with a streak
of darker red running along all the edges of the fragments; and the
progress of combustion might be noted by the differences of colour: in
some places pale; then a mottled zone, blending upwards with the
sweating patches under the smoke. Commonly the heap burns for three
months; hence a good manager takes care so to time his fires that a
supply of _mine_--as the calcined shale is technically named--is always
in readiness. Fifty tons of this burnt shale are required to make one
ton of alum.
We turned to the heap which I have mentioned as resembling a mound of
brick rubbish at a distance. One-third of it had been wheeled away to
the cisterns, exposing the interior, and I could see how the fire had
touched every part, and left its traces in the change of colour and the
narrow red border round each calcined chip. The pieces lie loosely
together, so that on digging away below, the upper part falls of itself.
The man who was filling the barrows had hacked out a cavernous hollow;
it seemed that a slip might be momentarily expected, for the top
overhung threateningly, and yet he continued to hack and dig with
apparent unconcern, and replied to the foreman's caution, "Oh! it won't
come down afore to-morrow. It'll give warning."
Now for the watery ordeal. On the sloping ground between the cliffs and
the sea, shallow pits or cisterns are sunk, nearly fifty feet long and
twenty wide, and so placed, with a bottom sloping from a depth of one
foot at one end to two feet at the other, as to communicate easily with
one another by pipes and gutters. Whether alum-works shall pay or not,
is said to depend in no small degree on the proper arrangement of the
pits. Each pit will contain forty wagon-loads of the mine. As soon as it
is full, liquor is pumped into it from a deep cistern covered by a shed,
and this at the end of three days is drawn off by the tap at the lower
end, and when drained the pit is again pumped full and soaked for two
days. Yet once more is it pumped full, but with water--producing first,
second, and third run, and sometimes a fourth--but the last is the
weakest, and is kept to be pumped up as liquor on a fresh pit for first
run. It would be poor economy to evaporate so weak a solution. Each pit
employs five men.
All this is carried on in the open air, with the sea lashing the shore
but a few yards off, and all around the signs of what to a stranger
appears but a rough and ready system. And in truth there must be
something wasteful in it, for all the alum is never abstracted. After
the third or fourth washing, the mine is shovelled from the pits and
flung away on the beach, where the sea soon levels it to a uniform
slope. In one of the so-called exhausted pits I saw many pieces touched,
as it were, by hoar frost, which was nothing but minute crystals of alum
formed on the surface, strongly acid to the taste.
The rest of the process was to be seen down at the works, so thither we
went; not by the way I came, for the foreman, scrambling up the side of
the gap, conducted me along the ledge at the top of the burning heap. He
walked through the stifling fumes without annoyance, while on me they
produced a painful sense of choking, with an impulse to run. Before we
had passed, however, he pushed aside a few of the upper pieces, and
showed me the dull glow of the fire beneath. Then we had more ledges
along the face of the cliff, and now and then to creep and jump; and we
crossed an old digging, which looked ugly with its heaps of waste and
half-starved patches of grass. All the way extends a course of long
wooden gutters, in which the first-run liquor was flowing in a
continuous stream to undergo its final treatment--another trial by fire.
Then into a low, darksome shed, where from one end to the other you see
nothing but leaden evaporating pans and cisterns, some steaming, and all
containing liquor in different states of preparation. That from which
the most water has been evaporated--the concentrated solution--has a
large cistern to itself, where its tendency to crystallize is assisted
by an admixture of liquor containing ammonia in solution, and
immediately the alum falls to the bottom in countless crystals. The
liquor above them, now become 'mother liquor,' or more familiarly
'mothers,' is drawn off, the crystals are washed clean in water, are
again dissolved, and once more boiled, mixed with gallons of mothers
remaining from former boilings. When of the required density, the liquor
is run off from the pan to the 'roching casks'--great butts rather, big
as a sugar hogshead, and taller; and in these is left to cool and
crystallize after its manner, from eight to ten days, according to the
season. The butts are constructed so as to take to pieces easily, and at
the right time the hoops are knocked off, the staves removed, and there
on the floor stands a great white cask of alum, solid all over, top,
bottom, and sides, except in its centre a quantity of liquor which has
not crystallized. This having been drawn off by a hole driven through,
the mass is then broken to pieces, and is fit for the market; and for
the use of dyers, leather-dressers, druggists, tallow-chandlers; for
bakers even, and other crafty traders.
Looked at from the outside, there is no beauty in the cask of alum; but
as soon as the interior is exposed, then the numberless crystals
shooting from every part, glisten again as the light streams in upon
them; and you acknowledge that the cunning by which they have been
produced from the dull slaty shale is a happy triumph of chemical
art--one that will stand a comparison with a recent triumph, the
extraction of brilliantly white candles from the great brown peat-bogs
of Ireland, or from Rangoon tar. Perhaps some readers will remember the
beautiful specimen of alum crystals--an entire half-tun that stood in
the nave of the Great Exhibition.
Alum is made near Glasgow from the shale of abandoned coal mines, soaked
in water without burning. After the works had been carried on for some
years, and the heap of refuse had spread over the neighbourhood to an
inconvenient extent, it was found that on burning this waste shale, it
would yield a second profitable supply of alum. Moreover, artificial
alum is manufactured in considerable quantities from a mixture of clay
and sulphuric acid.
In going about the works it was impossible not to be struck by the
contrast between the sooty aspect of the roofs, beams, and gangways, and
the whiteness of the crystal fringes in the pans, and the snowy patches
here and there where the vapour had condensed. And in an outhouse
wagon-loads of 'rough Epsoms' lay in a great white heap on the black
floor. This rough Epsoms, or sulphate of magnesia, is the crystals
thrown down by the mother-liquor after a second boiling.
In our goings to and fro, we talked of other things as well as alum; of
that other mineral wealth, the ironstone, to which Cleveland owes so
important a development of industry within the past fifteen years. The
existence of ironstone in the district had long been known; but not till
the foreman--jointly with his father--discovered a deposit near
Skinningrave, and drew attention to it, was any attempt made to work it.
Geologically the deposit is known as clayband ironstone; hence clay will
still make known the fame of this corner of Yorkshire, as when the old
couplet was current--
"Cleveland in the clay,
Carry in two shoon, bring one away."
If I liked the foreman at first sight, much more did I like him upon
acquaintance. He won my esteem as much by his frank and manly bearing,
as by his patient attentions and intelligent explanations; and I shook
his hand at parting with a sincere hope of having another talk with him
some day.