TIN-STREAMING
Remains of the tin-streamers--Dartmoor stream tin--Lode tin--The
dweller in the hut circles did not work the tin--The tin
trade with Britain--How tin was extracted--A furnace--Deep
Swincombe--Blowing-houses--The wheel introduced in the reign of
Elizabeth--Japanese primitive methods--Numerous blowing-house
ruins--The tin-mould stones--Merrivale Bridge--King's Oven--Its
present condition--Mining.
No one who has eyes in his head, and considers what he sees, if he has
been on Dartmoor, can have failed to observe how that every stream-bed
has been turned over, and how that every hollow in a hillside is
furrowed.
The tin-streamers who thus scarred the face of the moor carried on
their works far down below where the rivers debouch from the moor on to
the lowlands, but there the evidences of their toil have been effaced
by culture.
The tin found in the detritus of streams is the oxide, and is far purer
than tin found in the lode. Mining for tin was pursued on Dartmoor
during the Middle Ages to a limited extent only, and solely when the
stream tin was exhausted.
[Illustration: BLOWING-HOUSE UNDER BLACK TOR]
A very interesting excursion may be made from Douseland Station up the
Meavy valley to Nosworthy Bridge, above which several old tin-moulds
may be seen lying in the track beside the river, and tin-workings are
passed. But perhaps the most interesting portion of the walk is that up
the Nillacombe that opens on to the Meavy from the right below Kingset.
[Illustration: TIN-WORKINGS, NILLACOMBE.]
Above this the stream has been turned about and its bed torn up, and
rubble heaped in huge piles. Not only so, but the hill-slope to the
south is marked as with confluent smallpox, the result of the gropings
of miners after tin. They followed up every trickle from the side and
dug _costeening_, or _shoding_, pits everywhere in search of metal.
The upper waters of the Webburn have in like manner been explored,
and some idea of the extent to which the moor was lacerated by the
miners may be obtained from the Warren Inn on the road from Post
Bridge to Moreton, looking east, when the slopes of Headland Warren and
Challacombe will be seen seamed deeply.
The remains of the tinners have not been subjected to as full an
exploration as they merit, but certain results have nevertheless been
reached. One thing is abundantly clear, that all the tin-streaming was
done subsequently to the time when men occupied the hut circles. The
population living in them knew nothing of tin.
Diodorus Siculus, who wrote B.C. 8, says that the dwellers at Belerium,
a cape of Britain, mined and smelted tin. "After beating it up into
knucklebone shapes they carry it to a certain island lying off Britain,
named Ictis, for at ebb tides, the space between drying up, they carry
the tin in waggons thither ... and thence the merchants buy it from the
inhabitants and carry it over to Gaul, and lastly, travelling by land
through Gaul about thirty days, they bring down the loads on horses to
the mouth of the Rhine."
There can exist little doubt that Ictis is the same as Vectis, the
Isle of Wight. It is held that anciently the island was connected with
the mainland. The Roman station and harbour was at Brading. The early
workers first pounded the ore with stone crushers, and such have been
found. They then fanned it in the wind, which carried off the fine
light dust, and left the metal on the shovels on which they tossed
the ore and grit into the air. Beside some of the workings heaps of
this dust have been detected. The washing of the ore came later. When
sufficient had been collected, long troughs were sunk in the "calm,"
or native clay, and these were filled with charcoal; then the tin ore
was laid on this charcoal, and either more of this latter was heaped
above, or else peat was piled up, with layers of ore. Finally the whole
was kindled. No bellows were used, but a draught through the channel
kept the whole glowing, and the metal ran through the fire into the
bottom of the hollow, or ran out at the end, as this rude furnace was
constructed on an incline.
[Illustration: MORTAR-STONE, OKEFORD.]
In Staffordshire, at Kinver, and in the neighbourhood of Stourbridge,
in Worcestershire, I have seen banks and hedges made up of what are
locally called _burrs_. These consist of masses of sand and iron slag,
two feet in diameter, round, and concave on one side, convex on the
other. These burrs were formed in the primitive manufacture of iron,
which much resembled that of tin. Andrew Yarranton, in _England's
Improvement by Sea and Land_, 1698, says that he saw dug up near the
walls of Worcester the hearth of an old Roman iron-furnace.
"It was an open hearth upon which was placed alternately charcoal
and ironstone, to which fire being applied; it was urged by men
treading upon bellows. The operation was very slow and imperfect.
Unless the ore was very rich, not more than one hundredweight of
iron could be extracted in a day. The ironstone did not melt, but
was found at the bottom of the hearth in a large lump or bloom,
which was afterwards taken out and beaten under massive hammers
previous to its being worked into the required shape or form."
The _burrs_ found are the sand and iron mixed that encased the _bloom_,
which was taken out by pincers and worked on the anvil. The scoria that
encased the bloom was thrown aside, and yet contains more than one-half
of iron. The iron reduced in this simple manner never ran, but it
became soft like dough, and could be removed and beaten into shape.
The method of dealing with the tin was similar, only that in this
latter case the metal flowed. That foot bellows were employed before
the system of working bellows, and producing a continuous blast by
means of a water-wheel, is most probable. The foot bellows are known to
most primitive people, but in Agricola's illustration of the smelting
of tin none are shown. On the contrary, Æolus is represented in the
corner as blowing a natural blast.
[Illustration: SLAG-POUNDING HOLLOWS, GOBBETTS.]
The book of Agricola, published in 1556, shows that this primitive
method was still in practice so late as the middle of the sixteenth
century.
But this clumsy method could not be long practised on Dartmoor, where
fuel--except peat--was scarce; and it gave way to a furnace of better
construction, where the receiver was circular, and a draught-hole was
at the bottom. One of these has been dug out and carefully examined at
Deep Swincombe.
[Illustration: SMELTING ORE. (_After Agricola._)]
[Illustration: PLAN OF BLOWING-HOUSE, DEEP SWINCOMBE.]
It consists of a single chamber, 18 feet by 11 feet, rudely constructed
of masses of granite resting on one another by their own weight and
unset in mortar or in clay. The entrance was narrow and low. On one
side was the furnace, constructed of granite, one slab set upright to
form a side, and the back and other side built up rudely. A fragment
of the receptacle for the molten tin was found, with a receiver and
channel cut in it. Pottery was also found, which was of a very early
description. It was submitted to the late Sir Wollaston Franks, of the
British Museum, who said that he would have attributed it to the Celtic
period but for the bold scores made at the starting-point of a handle,
which are characteristic of Anglo-Saxon pottery.
At the extremity furthest from the door was a _cache_ in the thickness
of the wall, formed something like a kistvaen, as a place in which
to store the metal and tools. The whole structure was banked up with
rubble and turf.
Outside to the south still lies a mould-stone, a slab of elvan, in
which the mould had been cut, measuring 26 inches long by 12 inches at
one end and 15 at the other, and 5 inches deep.
That this is the earliest tin-furnace yet discovered on Dartmoor admits
of no doubt. The curious mould-stone is quite different in shape from
any others found on the moor. No mortar-stones were discovered, and
this also is a token of antiquity.
The earliest smelting arrangements must have been very crude, and much
tin was left in the slag. Until recently the Malays threw away their
slags, which contained as much as 40 per cent. of tin. As there have
been no mortar-stones found at Deep Swincombe, it is to be presumed
that the tinners disregarded their slags. These have not, moreover,
been found. The reason was this--the sets had been reworked at a later
time by the tinners at Gobbetts, further down the river. These later
men had stone mortars and a crazing mill, and finding these rich slags,
removed them, pounded them up in the hollowed mortar-stones, that may
be seen _in situ_ at Gobbetts, and re-smelted them. Deep Swincombe has
all the appearance of having been much pulled about by tinners since
the first furnace was erected.
[Illustration: TIN-MOULD, DEEP SWINCOMBE.]
The tin running out of the furnace was allowed to flow into holes in
the ground, and thence was ladled whilst in a molten condition and
poured into the moulds.
Mr. Gowland has given a most interesting account of the manner in which
the metals are extracted from their ores in Japan.[12] This shows how
that the primitive methods are still in practice there. He says:--
"Although tin ore is found and worked in Japan in several
localities, there is but one ancient mine in the country. It is
situated in Taniyama, in the province of Satsuma. The excavations
of the old miners here are of a most extensive character, the
hillsides in places being literally honeycombed by their burrows,
indicating the production in past times of large quantities of the
metal. No remains, however, have been found to give any clue to the
date of the earliest workings. But whatever may have been their
date, the processes and appliances of the early smelters could not
have been more primitive than those I found in use when I visited
the mines in 1883.
"The ore was roughly broken up by hammers on stone anvils, then
reduced to a coarse powder with the pounders used for decorticating
rice, the mortars being large blocks of stone with roughly hollowed
cavities.
"It was finally ground in stone querns, and washed by women in a
stream to remove the earthy matter and foreign minerals with which
it was contaminated. The furnace in which the ore was smelted is
exactly the same as that used for copper ores, excepting that it
is somewhat less in diameter. The ore was charged into it wet, in
alternate layers with charcoal, and the process was conducted in
precisely the same way as in smelting oxidised copper ores. The tin
obtained was laded out of the furnace into moulds of clay."
The furnace employed for copper is also described by Mr. Gowland:--
"An excavation, measuring about 4 feet long, 4 feet wide, and 2
feet deep, is made, and this is filled with dry clay carefully
beaten down. In the centre of this bed of clay a shallow,
conical-shaped hole is scooped out. The hole is then lined with a
layer, about three inches thick, of damp clay mixed with charcoal,
and the furnace is complete.
[Illustration: SMELTING TIN IN JAPAN.]
"It has no apertures either for the injection of the blast or for
tapping out the metal. A blast of air is supplied to it generally
from two bellows, placed behind a wall of wattle well coated with
clay, by which they and the men working them are protected from
the heat. The blast is led from each bellows by a bamboo tube,
terminating in a very long nozzle of clay, which rests on the edge
of the furnace cavity."
At Deep Swincombe no bellows were used; the draught probably came in
through the hole behind the furnace.
But in the reign of Queen Elizabeth a great revolution in the smelting
of tin was wrought by the introduction of German workmen and their
improved methods. They brought in the water-wheel. The ruins that are
found in such abundance of "blowing-houses," as they are called--one at
the least beside every considerable stream--belong, for the most part,
to the Elizabethan period. They have their "leats" for carrying water
to them, and their pits for tiny wheels that worked the bellows.
The situation of these smelting-houses may be found usually by the
mould-stones that lie near them. There is one below the slide or fall
of the Yealm, with its moulds in and by it, and another just above the
fall. There is one near the megalithic remains at Drizzlecombe, also
with its mould-stones. But it is unnecessary to particularise when they
are so numerous. I will, however, quote Mr. R. Burnard's description of
two in the Walkham valley as typical:
"The first is about 250 yards above Merrivale Bridge, on the
left bank of the river. One jamb is erect, and, like most of the
doorways of Dartmoor blowing-houses, was low, and to be entered
necessitated an almost all-fours posture. Very little of the walls
is standing, but what remains is composed of large moor-stones,
dry laid. Near the entrance is a stone, 3 feet long and 2½ feet
wide, containing a mould, which at the top is 18 inches long, 13
inches wide, and 6 inches deep. The sides are bevelled, so that the
bottom length is 12½ inches, with a width of 7 inches at one end
and 8 inches at the other. One end of the mould has a narrow gutter
leading from the top to halfway down the mould. This was probably
used for the insertion of a piece of iron prior to the metal being
run in, thus permitting the easy withdrawal of the block of tin
when cool from the mould. This stone also contains a small bevelled
ingot or sample mould, 4 inches long, 2 inches wide, and 1¼ inches
deep.
"A water-wheel probably stood in the eastern recess of the house,
for there is a covered drain leading from here right under the
house and out at the western end, where the water was discharged
into the river. Traces of the leat which supplied the motive power
to this wheel may also be seen.
"What appear to be the remains of the furnace, consisting of
massive stones placed vertically, and inclosing a small rectangular
space, are plainly visible. In this place, lying askew, as if it
had been thrown out of position, is a large stone containing a
long, shallow cavity, which may have been the bottom of the furnace
or 'float,' _i.e._ the cavity in which the molten tin collected
before being ladled into the mould.
"This ruin lies at the nether end of deep, open cuttings, which
start from near Rundlestone Corner, and are continued right down to
the Walkham.
"About 1,000 yards up stream is the ruin of the other
blowing-house, with remains of a wheel-pit and a leat. There
is also a stone containing a mould 16 inches long at the top,
11 inches wide, and 6 inches deep. It is bevelled, so that the
bottom length is 12½ inches, with a width of 8 inches. Like the
mould-stone in the ruin below, it contains a sample ingot mould 3½
inches long, 3 inches wide, and 2 inches deep. The remains in these
ruins are very similar to each other, and these blowing-houses
were probably smelting during the same period, indicating that a
considerable quantity of tin was raised in their neighbourhood."[13]
Anciently, before the introduction of the wheel, the smelting-place
above all others was at King's Oven, or Furnum Regis, near the
Warren Inn, between Post Bridge and Moreton. It is mentioned in the
_Perambulation of Dartmoor_, made in 1240. It consists of a circular
inclosure of about seventy-two yards in diameter, forming a pound, with
the remains of a quadrangular building in it. The furnace itself was
destroyed some years ago. When the inclosure was made it was carried to
a cairn that was in part demolished, to serve to form the bank of the
pound. This cairn was ringed about with upright stones, and contained a
kistvaen. The latter was rifled, and most of the stones removed to form
the walls; but a few of the inclosing uprights were not meddled with,
and between two was found firmly wedged a beautiful flint scraper.
As the drift tin was exhausted, and the slag of the earlier miners was
used up, it became necessary to run adits for tin, and work the veins.
These adits remain in several places, and where they have been opened
have yielded up iron bars and picks. But these are not more ancient
than mediæval times, probably late in them. That gold was found in the
granite rubble of the stream-beds is likely. A model of a gold-washing
apparatus was found on the moor a few years ago. It was made of zinc.
According to an old Irish historical narrative, a bard was wont
to carry a wand of "white bronze" or tin, and his shoes were also
tin-plated.[14] One wonders whether at any time a bard thus shod and
with his rod of office strode over Dartmoor and chanted historic
ballads there!
For such as would care to see these dry bones of antiquarian research
into the past of tin-streamers clothed with flesh, I must refer them to
my novel of _Guavas the Tinner_, in which I have described the mode of
life of the metal-seekers on the moor in the time of Elizabeth.
FOOTNOTES:
[12] _Archæologia_, vol. lvi. part 2, 1899.
[13] _Dartmoor Pictorial Records_, 1893.
[14] _Silva Gadhelica_, ii. p. 271.