Book V.

BOOK V.
In the last book I have explained the methods of
delimiting the meers along each kind of vein, and
the duties of mine officials. In this book 1 I will
in like manner explain the principles of under−
ground mining and the art of surveying. First
then, I will proceed to deal with those matters
which pertain to the former heading, since both the
subject and methodical arrangement require it.
And so I will describe first of all the digging of
shafts, tunnels, and drifts on venae profundae; next I will discuss the good
indications shown by canales 2 , by the materials which are dug out, and by
the rocks; then I will speak of the tools by which veins and rocks are broken
down and excavated; the method by which fire shatters the hard veins;
and further, of the machines with which water is drawn from the shafts
and air is forced into deep shafts and long tunnels, for digging is impeded
by the inrush of the former or the failure of the latter; next I will deal
with the two kinds of shafts, and with the making of them and of tunnels;
and finally, I will describe the method of mining venae dilatatae, venae cumulatae, and stringers.
1
188
Now when a miner discovers a vena profunda he begins sinking a shaft
and above it sets up a windlass, and builds a shed over the shaft to prevent
the rain from falling in, lest the men who turn the windlass be numbed
by the cold or troubled by the rain. The windlass men also place their
barrows in it, and the miners store their iron tools and other implements therein.
Next to the shaft−house another house is built, where the mine foreman and the
other workmen dwell, and in which are stored the ore and other things which
are dug out. Although some persons build only one house, yet because
sometimes boys and other living things fall into the shafts, most miners
deliberately place one house apart from the other, or at least separate them
by a wall.
Now a shaft is dug, usually two fathoms long, two−thirds of a fathom
wide, and thirteen fathoms deep; but for the purpose of connecting with a
tunnel which has already been driven in a hill, a shaft may be sunk to a
depth of only eight fathoms, at other times to fourteen, more or less 3 . A
shaft may be made vertical or inclined, according as the vein which the
miners follow in the course of digging is vertical or inclined. A tunnel is a
subterranean ditch driven lengthwise, and is nearly twice as high as it is
broad, and wide enough that workmen and others may be able to pass and
carry their loads. It is usually one and a quarter fathoms high, while
its width is about three and three−quarters feet. Usually two workmen are
required to drive it, one of whom digs out the upper and the other the lower
part, and the one goes forward, while the other follows closely after. Each
sits upon small boards fixed securely from the footwall to the hangingwall,
or if the vein is a soft one, sometimes on a wedge−shaped plank fixed on to the
vein itself. Miners sink more inclined shafts than vertical, and some of each
kind do not reach to tunnels, while some connect with them. But as for
some shafts, though they have already been sunk to the required depth,
the tunnel which is to pierce the mountain may not yet have been driven
far enough to connect with them.
It is advantageous if a shaft connects with a tunnel, for then the miners
and other workmen carry on more easily the work they have undertaken;
but if the shaft is not so deep, it is usual to drift from one or both sides of it.
From these openings the owner or foreman becomes acquainted with the
veins and stringers that unite with the principal vein, or cut across it, or

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divide it obliquely; however, my discourse is now concerned mainly with
vena profunda, but most of all with the metallic material which it contains.
THREE VERTICAL SHAFTS, OF WHICH THE FIRST, A, DOES NOT REACH THE TUNNEL; THE
SECOND, B, REACHES THE TUNNEL; TO THE THIRD, C, THE TUNNEL HAS NOT YET BEEN
DRIVEN. DTUNNEL.

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Excavations of this kind were called by the Greeks kruptai for, extending
along after the manner of a tunnel, they are entirely hidden within the
THREE INCLINED SHAFTS, OF WHICH A DOES NOT YET REACH THE TUNNEL; B REACHES THE
TUNNEL; TO THE THIRD, C, THE TUNNEL HAS NOT YET BEEN DRIVEN. DTUNNEL.

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ground. This kind of an opening, however, differs from a tunnel in that it
is dark throughout its length. whereas a tunnel has a mouth open to daylight.
ASHAFT. B, CDRIFT. DANOTHER SHAFT. ETUNNEL. FMOUTH OF TUNNEL.

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I have spoken of shafts, tunnels, and drifts. I will now speak of the
indications given by the canales, by the materials which are dug out, and by
the rocks. These indications, as also many others which I will explain, are
to a great extent identical in venae dilatatae and venae cumulatae with venae
profundae.
When a stringer junctions with a main vein and causes a swelling, a
shaft should be sunk at the junction. But when we find the stringer inter−
secting the main vein crosswise or obliquely, if it descends vertically down
to the depths of the earth, a second shaft should be sunk to the point where
the stringer cuts the main vein; but if the stringer cuts it obliquely the
shaft should be two or three fathoms back, in order that the junction may
be pierced lower down. At such junctions lies the best hope of finding the
ore for the sake of which we explore the ground, and if ore has already been
found, it is usually found in much greater abundance at that spot. Again,
if several stringers descend into the earth, the miner, in order to pierce
through the point of contact, should sink the shaft in the midst of these
stringers, or else calculate on the most prominent one.
Since an inclined vein often lies near a vertical vein, it is advisable
to sink a shaft at the spot where a stringer or cross−vein cuts them both;
or where a vena dilatata or a stringer dilatata passes through, for minerals
are usually found there. In the same way we have a good prospect of finding
metal at the point where an inclined vein joins a vertical one; this is why
miners cross−cut the hangingwall or footwall of a main vein, and in these
openings seek for a vein which may junction with the principal vein a few
fathoms below. Nay, further, these same miners, if no stringer or cross−
vein intersects the main vein so that they can follow it in their workings,
even cross−cut through the solid rock of the hangingwall or footwall. These
cross−cuts are likewise called " kruptai/, " whether the beginning of the
opening which has to be undertaken is made from a tunnel or from a drift.
Miners have some hope when only a cross vein cuts a main vein. Further,
if a vein which cuts the main vein obliquely does not appear anywhere
beyond it, it is advisable to dig into that side of the main vein toward which
the oblique vein inclines, whether the right or left side, that we may ascer−
tain if the main vein has absorbed it; if after cross−cutting six fathoms it
is not found, it is advisable to dig on the other side of the main vein, that
we may know for certain whether it has carried it forward. The owners
of a main vein can often dig no less profitably on that side where the vein
which cuts the main vein again appears, than where it first cuts it; the

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owners of the intersecting vein, when that is found again, recover their title,
which had in a measure been lost.
The common miners look favourably upon the stringers which come
from the north and join the main vein; on the other hand, they look
unfavourably upon those which come from the south, and say that these do
much harm to the main vein, while the former improve it. But I think
that miners should not neglect either of them: as I showed in Book III,
experience does not confirm those who hold this opinion about veins, so now

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again I could furnish examples of each kind of stringers rejected by the
common miners which have proved good, but I know this could be of little
or no benefit to posterity.
If the miners find no stringers or veins in the hangingwall or footwall of
the main vein, and if they do not find much ore, it is not worth while to
undertake the labour of sinking another shaft. Nor ought a shaft to be sunk
where a vein is divided into two or three parts, unless the indications are
satisfactory that those parts may be united and joined together a little later.
Further, it is a bad indication for a vein rich in mineral to bend and turn
hither and thither, for unless it goes down again into the ground vertically or
inclined, as it first began, it produces no more metal; and even though it
does go down again, it often continues barren. Stringers which in their
outcrops bear metals, often disappoint miners, no metal being found in depth.
Further, inverted seams in the rocks are counted among the bad indications.
The miners hew out the whole of solid veins when they show clear evidence
of being of good quality; similarly they hew out the drusy 4 veins,
especially if the cavities are plainly seen to have formerly borne metal, or
if the cavities are few and small. They do not dig barren veins through
which water flows, if there are no metallic particles showing; occasionally,
however, they dig even barren veins which are free from water, because
of the pyrites which is devoid of all metal, or because of a fine black soft
substance which is like wool. They dig stringers which are rich in metal,
or sometimes, for the purpose of searching for the vein, those that are devoid
of ore which lie near the hangingwall or footwall of the main vein. This
then, generally speaking, is the mode of dealing with stringers and veins.
Let us now consider the metallic material which is found in the canales
of venae profundae, venae dilatatae, and venae cumulatae, being in all these
either cohesive and continuous, or scattered and dispersed among them,
or swelling out in bellying shapes, or found in veins or stringers which
originate from the main vein and ramify like branches; but these latter veins
and stringers are very short, for after a little space they do not appear again.
If we come across a small quantity of metallic material it is an indication;
but if a large quantity, it is not an "indication," but the very thing for
which we explore the earth. As soon as a miner who searches for veins
discovers pure metal or minerals, or rich metallic material, or a great
abundance of material which is poor in metal, let him sink a shaft on the
spot without any delay. If the material appears more abundant or of better

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quality on the one side, he will incline his digging in that direction.
Gold, silver, copper, and quicksilver are often found native 5 ; less
often iron and bismuth; almost never tin and lead. Nevertheless tin−stone
is not far removed from the pure white tin which is melted out of them, and
galena, from which lead is obtained, differs little from that metal itself.
Now we may classify gold ores. Next after native gold, we come to the

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rudis 6 , of yellowish green, yellow, purple, black, or outside red and inside
gold colour. These must be reckoned as the richest ores, because the gold
exceeds the stone or earth in weight. Next come all gold ores of which each.
one hundred librae contains more than three uncíae of gold 7 ; for although but
a small proportion of gold is found in the earth or stone, yet it equals in value
other metals of greater weight. 8 All other gold ores are considered poor, because

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the earth or stone too far outweighs the gold. A vein which contains a
larger proportion of silver than of gold is rarely found to be a rich one.
Earth, whether it be dry or wet, rarely abounds in gold; but in dry earth
there is more often found a greater quantity of gold, especially if it has the

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appearance of having been melted in a furnace, and if it is not lacking in
scales resembling mica. The solidified juices, azure, chrysocolla, orpiment,
and realgar, also frequently contain gold. Likewise native or rudís gold is
found sometimes in large, and sometimes in small quantities in quartz,

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schist, marble, and also in stone which easily melts in fire of the second
degree, and which is sometimes so porous that it seems completely decom−
posed. Lastly, gold is found in pyrites, though rarely in large quantities.
When considering silver ores other than native silver, those ores are

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classified as rich, of which each one hundred líbrae contains more than three
librae of silver. This quality comprises rudis silver, whether silver glance or
ruby silver, or whether white, or black, or grey, or purple, or yellow, or liver−

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coloured, or any other. Sometimes quartz, schist, or marble is of this quality
also, if much native or rudis silver adheres to it. But that ore is considered
of poor quality if three librae of silver at the utmost are found in each
one hundred líbrae of it. 9 Silver ore usually contains a greater quantity

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than this, because Nature bestows quantity in place of quality; such ore
is mixed with all kinds of earth and stone compounds, except the various
kinds of rudís silver; especially with pyrites, cadmia metallíca fossílís, galena,
stibíum, and others.

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As regards other kinds of metal, although some rich ores are found,
still, unless the veins contain a large quantity of ore, it is very rarely worth
while to dig them. The Indians and some other races do search for gems in
veins hidden deep in the earth, but more often they are noticed from their
clearness, or rather their brilliancy, when metals are mined. When they
outcrop, we follow veins of marble by mining in the same way as is
done with rock or building−stones when we come upon them. But
gems, properly so called, though they sometimes have veins of their own,
are still for the most part found in mines and rock quarries, as the
lodestone in iron mines, the emery in silver mines, the lapís judaícus,
trochítes, and the like in stone quarries where the diggers, at the bidding
of the owners, usually collect them from the seams in the rocks. 10 Nor does the
miner neglect the digging of "extraordinary earths," 11 whether they are found

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in gold mines, silver mines, or other mines; nor do other miners neglect them
if they are found in stone quarries, or in their own veins; their value is usually
indicated by their taste. Nor, lastly, does the miner fail to give attention to
the solidified juices which are found in metallic veins, as well as in their own
veins, from which he collects and gathers them. But I will say no more
on these matters, because I have explained more fully all the metals and
mineral substances in the books " De Natura Fossilium. "
But I will return to the indications. If we come upon earth which is
like lute, in which there are particles of any sort of metal, native or rudis,
the best possible indication of a vein is given to miners, for the metallic
material from which the particles have become detached is necessarily close
by. But if this kind of earth is found absolutely devoid of all metallic
material, but fatty, and of white, green, blue, and similar colours, they must
not abandon the work that has been started. Miners have other indications in
the veins and stringers, which I have described already, and in the rocks, about
which I will speak a little later. If the miner comes across other dry earths
which contain native or rudis metal, that is a good indication; if he comes
across yellow, red, black, or some other "extraordinary" earth, though it is
devoid of mineral, it is not a bad indication. Chrysocolla, or azure, or verdigris,
or orpiment, or realgar, when they are found, are counted among the good
indications. Further, where underground springs throw up metal we ought
to continue the digging we have begun, for this points to the particles having
been detached from the main mass like a fragment from a body. In the
same way the thin scales of any metal adhering to stone or rock are counted
among the good indications. Next, if the veins which are composed partly
of quartz, partly of clayey or dry earth, descend one and all into the depths
of the earth together, with their stringers, there is good hope of metal being
found; but if the stringers afterward do not appear, or little metallic
material is met with, the digging should not be given up until there is nothing
remaining. Dark or black or horn or liver−coloured quartz is usually a good
sign; white is sometimes good, sometimes no sign at all. But calc−spar,
showing itself in a vena profunda, if it disappears a little lower down is not a
good indication; for it did not belong to the vein proper, but to some stringer.
Those kinds of stone which easily melt in fire, especially if they are translucent
(fluorspar?), must be counted among the medium indications, for if other
good indications are present they are good, but if no good indications are
present, they give no useful significance. In the same way we ought to form
our judgment with regard to gems. Veins which at the hangingwall and
footwall have horn−coloured quartz or marble, but in the middle clayey

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earth, give some hope; likewise those give hope in which the hangingwall
or footwall shows iron−rust coloured earth, and in the middle greasy and
sticky earth; also there is hope for those which have at the hanging or footwall
that kind of earth which we call "soldiers' earth," and in the middle black
earth or earth which looks as if burnt. The special indication of gold is
orpiment; of silver is bismuth and stibium; of copper is verdigris, melantería,
sory, chalcitis, misy, and vitriol; of tin is the large pure black stones of

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which the tin itself is made, and a material they dig up resembling litharge;
of iron, iron rust. Gold and copper are equally indicated by chrysocolla and
azure; silver and lead, by the lead. But, though miners rightly
call bismuth "the roof of silver," and though copper pyrites is the common
parent of vitriol and melantería, still these sometimes have their own
peculiar minerals, just as have orpiment and stibium.
Now, just as certain vein materials give miners a favourable indication,
so also do the rocks through which the canales of the veins wind their
way, for sand discovered in a mine is reckoned among the good indications,
especially if it is very fine. In the same way schist, when it is of a
bluish or blackish colour, and also limestone, of whatever colour it may be, is
a good sign for a silver vein. There is a rock of another kind that is a good sign;
in it are scattered tiny black stones from which tin is smelted; especially when
the whole space between the veins is composed of this kind of rock.
Very often indeed, this good kind of rock in conjunction with valuable
stringers contains within its folds the canales of mineral bearing veins: if
it descends vertically into the earth, the benefit belongs to that mine in
which it is seen first of all; if inclined, it benefits the other neighbouring
mines 12 . As a result the miner who is not ignorant of geometry can calculate
from the other mines the depth at which the canales of a vein bearing rich
metal will wind its way through the rock into his mine. So much for these
matters.
I now come to the mode of working, which is varied and complex, for in
some places they dig crumbling ore, in others hard ore, in others a harder
ore, and in others the hardest kind of ore. In the same way, in some places
the hangingwall rock is soft and fragile, in others hard, in others harder, and
in still others of the hardest sort. I call that ore "crumbling" which is com−
posed of earth, and of soft solidified juices; that ore "hard" which is composed
of metallic minerals and moderately hard stones, such as for the most part
are those which easily melt in a fire of the first and second orders, like lead
and similar materials. I call that ore "harder" when with those I have already
mentioned are combined various sorts of quartz, or stones which easily melt
in fire of the third degree, or pyrites, or cadmia, or very hard marble. I call
that ore hardest, which is composed throughout the whole vein of these hard
stones and compounds. The hanging or footwalls of a vein are hard, when
composed of rock in which there are few stringers or seams; harder, in
which they are fewer; hardest, in which they are fewest or none at all.
When these are absent, the rock is quite devoid of water which softens

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it. But the hardest rock of the hanging or footwall, however, is seldom as
hard as the harder class of ore.
Miners dig out crumbling ore with the pick alone. When the metal
has not yet shown itself, they do not discriminate between the hangingwall
and the veins; when it has once been found, they work with the utmost care.
For first of all they tear away the hangingwall rock separately from the vein,
afterward with a pick they dislodge the crumbling vein from the footwall

[208]
into a dish placed underneath to prevent any of the metal from falling to
the ground. They break a hard vein loose from the footwall by blows with
a hammer upon the first kind of iron tool 13 , all of which are designated by
appropriate names, and with the same tools they hew away the hard hanging−
wall rock. They hew out the hangingwall rock in advance more frequently, the
rock of the footwall more rarely; and indeed, when the rock of the footwall
resists iron tools, the rock of the hangingwall certainly cannot be broken unless
it is allowable to shatter it by fire. With regard to the harder veins which are
tractable to iron tools, and likewise with regard to the harder and hardest
kind of hangingwall rock, they generally attack them with more powerful
iron tools, in fact, with the fourth kind of iron tool, which are called by their
appropriate names; but if these are not ready to hand, they use two or
three iron tools of the first kind together. As for the hardest kind of metal−
bearing vein, which in a measure resists iron tools, if the owners of the
neighbouring mines give them permission, they break it with fires. But if
these owners refuse them permission, then first of all they hew out the rock of
the hangingwall, or of the footwall if it be less hard; then they place timbers
set in hitches in the hanging or footwall, a little above the vein, and from
the front and upper part, where the vein is seen to be seamed with small
cracks, they drive into one of the little cracks one of the iron tools which
I have mentioned; then in each fracture they place four thin iron
blocks, and in order to hold them more firmly, if necessary, they place
as many thin iron plates back to back; next they place thinner iron
plates between each two iron blocks, and strike and drive them by
turns with hammers, whereby the vein rings with a shrill sound; and the
moment when it begins to be detached from the hangingwall or footwall
rock, a tearing sound is heard. As soon as this grows distinct the miners
hastily flee away; then a great crash is heard as the vein is broken and torn,
and falls down. By this method they throw down a portion of a vein weigh−
ing a hundred pounds more or less. But if the miners by any other method
hew the hardest kind of vein which is rich in metal, there remain certain
cone−shaped portions which can be cut out afterward only with difficulty. As
for this knob of hard ore, if it is devoid of metal, or if they are not allowed to
apply fire to it, they proceed round it by digging to the right or left, because
it cannot be broken into by iron wedges without great expense. Meantime,
while the workmen are carrying out the task they have undertaken, the
depths of the earth often resound with sweet singing, whereby they lighten a
toil which is of the severest kind and full of the greatest dangers.
As I have just said, fire shatters the hardest rocks, but the method of its

[209]
application is not simple 14 . For if a vein held in the rocks cannot be hewn

[210]
out because of the hardness or other difficulty, and the drift or tunnel is
low, a heap of dried logs is placed against the rock and fired; if the drift or
tunnel is high, two heaps are necessary, of which one is placed above the
other, and both burn until the fire has consumed them. This force does not
generally soften a large portion of the vein, but only some of the surface.
When the rock in the hanging or footwall can be worked by the iron tools
and the vein is so hard that it is not tractable to the same tools, then the
walls are hollowed out; if this be in the end of the drift or tunnel or above
or below, the vein is then broken by fire, but not by the same method; for
if the hollow is wide, as many logs are piled into it as possible, but if narrow,
only a few. By the one method the greater fire separates the vein more
completely from the footwall or sometimes from the hangingwall, and by the
other, the smaller fire breaks away less of the vein from the rock, because in
that case the fire is confined and kept in check by portions of the rock which
surround the wood held in such a narrow excavation. Further, if the
excavation is low, only one pile of logs is placed in it, if high, there are
two, one placed above the other, by which plan the lower bundle being
kindled sets alight the upper one; and the fire being driven by the draught
into the vein, separates it from the rock which, however hard it may be, often
becomes so softened as to be the most easily breakable of all. Applying this
principle, Hannibal, the Carthaginian General, imitating the Spanish miners,

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overcame the hardness of the Alps by the use of vinegar and fire. Even
if a vein is a very wide one, as tin veins usually are, miners excavate into the
small streaks, and into those hollows they put dry wood and place amongst
them at frequent intervals sticks, all sides of which are shaved down fan−
shaped, which easily take light, and when once they have taken fire com−
municate it to the other bundles of wood, which easily ignite.
AKINDLED LOGS. BSTICKS SHAVED DOWN FAN−SHAPED. CTUNNEL.
While the heated veins and rock are giving forth a foetid vapour and the
shafts or tunnels are emitting fumes, the miners and other workmen do not
go down in the mines lest the stench affect their health or actually kill them,
as I will explain in greater detail when I come to speak of the evils which
affect miners. The Bergmeister, in order to prevent workmen from being
suffocated, gives no one permission to break veins or rock by fire in shafts or
tunnels where it is possible for the poisonous vapour and smoke to permeate
the veins or stringers and pass through into the neighbouring mines, which
have no hard veins or rock. As for that part of a vein or the surface of the
rock which the fire has separated from the remaining mass, if it is overhead,
the miners dislodge it with a crowbar, or if it still has some degree of hardness,
they thrust a smaller crowbar into the cracks and so break it down, but if

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it is on the sides they break it with hammers. Thus broken off, the rock
tumbles down; or if it still remains, they break it off with picks. Rock
and earth on the one hand, and metal and ore on the other, are filled into
buckets separately and drawn up to the open air or to the nearest tunnel.
If the shaft is not deep, the buckets are drawn up by a machine turned by
men; if it is deep, they are drawn by machines turned by horses.
It often happens that a rush of water or sometimes stagnant air hinders
the mining; for this reason miners pay the greatest attention to these
matters, just as much as to digging, or they should do so. The water of the
veins and stringers and especially of vacant workings, must be drained out
through the shafts and tunnels. Air, indeed, becomes stagnant both in
tunnels and in shafts; in a deep shaft, if it be by itself, this occurs if it is
neither reached by a tunnel nor connected by a drift with another shaft;
this occurs in a tunnel if it has been driven too far into a mountain and no
shaft has yet been sunk deep enough to meet it; in neither case can the
air move or circulate. For this reason the vapours become heavy and
resemble mist, and they smell of mouldiness, like a vault or some under−
ground chamber which has been completely closed for many years. This
suffices to prevent miners from continuing their work for long in these places,
even if the mine is full of silver or gold, or if they do continue, they cannot
breathe freely and they have headaches; this more often happens if they
work in these places in great numbers, and bring many lamps, which then
supply them with a feeble light, because the foul air from both lamps and
men make the vapours still more heavy.
A small quantity of water is drawn from the shafts by machines of
different kinds which men turn or work. If so great a quantity has flowed
into one shaft as greatly to impede mining, another shaft is sunk some
fathoms distant from the first, and thus in one of them work and labour are
carried on without hindrance, and the water is drained into the other, which
is sunk lower than the level of the water in the first one; then by these
machines or by those worked by horses, the water is drawn up into the drain
and flows out of the shaft−house or the mouth of the nearest tunnel. But
when into the shaft of one mine, which is sunk more deeply, there flows all
the water of all the neighbouring mines, not only from that vein in which
the shaft is sunk, but also from other veins, then it becomes necessary for a
large sump to be made to collect the water; from this sump the water is
drained by machines which draw it through pipes, or by ox−hides, about
which I will say more in the next book. The water which pours into the

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tunnels from the veins and stringers and seams in the rocks is carried
away in the drains.
Air is driven into the extremities of deep shafts and long tunnels by
powerful blowing machines, as I will explain in the following book, which
will deal with these machines also. The outer air flows spontaneously into
the caverns of the earth, and when it can pass through them comes out again.
This, however, comes about in different ways, for in spring and summer it
flows into the deeper shafts, traverses the tunnels or drifts, and finds its way

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out of the shallower shafts; similarly at the same season it pours into the
lowest tunnel and, meeting a shaft in its course, turns aside to a higher tunnel
and passes out therefrom; but in autumn and winter, on the other hand, it
enters the upper tunnel or shaft and comes out at the deeper ones. This
change in the flow of air currents occurs in temperate regions at the beginning
of spring and the end of autumn, but in cold regions at the end of spring
and the beginning of autumn. But at each period, before the air regularly
assumes its own accustomed course, generally for a space of fourteen days
it undergoes frequent variations, now blowing into an upper shaft or
tunnel, now into a lower one. But enough of this, let us now proceed to
what remains.
There are two kinds of shafts, one of the depth already described, of
which kind there are usually several in one mine; especially if the mine is
entered by a tunnel and is metal−bearing. For when the first tunnel is
connected with the first shaft, two new shafts are sunk; or if the inrush of
water hinders sinking, sometimes three are sunk; so that one may take
the place of a sump and the work of sinking which has been begun may be
continued by means of the remaining two shafts; the same is done in the
case of the second tunnel and the third, or even the fourth, if so many are
driven into a mountain. The second kind of shaft is very deep, sometimes
as much as sixty, eighty, or one hundred fathoms. These shafts continue
vertically toward the depths of the earth, and by means of a hauling−rope
the broken rock and metalliferous ores are drawn out of the mine; for which
reason miners call them vertical shafts. Over these shafts are erected
machines by which water is extracted; when they are above ground the
machines are usually worked by horses, but when they are in tunnels, other
kinds are used which are turned by water−power. Such are the shafts which
are sunk when a vein is rich in metal.
Now shafts, of whatever kind they may be, are supported in various
ways. If the vein is hard, and also the hanging and footwall rock, the shaft
does not require much timbering, but timbers are placed at intervals, one end
of each of which is fixed in a hitch cut into the rock of the hangingwall and
the other fixed into a hitch cut in the footwall. To these timbers are fixed
small timbers along the footwall, to which are fastened the lagging and
ladders. The lagging is also fixed to the timbers, both to those which screen
off the shaft on the ends from the vein, and to those which screen off the
rest of the shaft from that part in which the ladders are placed. The lagging
on the sides of the shaft confine the vein, so as to prevent fragments of it

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which have become loosened by water from dropping into the shaft and
terrifying, or injuring, or knocking off the miners and other workmen who
are going up or down the ladders from one part of the mine to another. For
the same reason, the lagging between the ladders and the haulage−way on
the other hand, confine and shut off from the ladders the fragments of rock
which fall from the buckets or baskets while they are being drawn up;
moreover, they make the arduous and difficult descent and ascent to appear
less terrible, and in fact to be less dangerous.

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If a vein is soft and the rock of the hanging and footwalls is weak,
a closer structure is necessary; for this purpose timbers are joined together
in rectangular shapes and placed one after the other without a break. These
AWALL PLATES. BDIVIDERS. CLONG END POSTS. DEND PLATES.

[217]
are arranged on two different systems; for either the square ends of the
timbers, which reach from the hangingwall to the footwall, are fixed into corres−
ponding square holes in the timbers which lie along the hanging or footwall,
or the upper part of the end of one and the lower part of the end of the other
are cut out and one laid on the other. The great weight of these joined
timbers is sustained by stout beams placed at intervals, which are deeply set
into hitches in the footwall and hangingwall, but are inclined. In order that
these joined timbers may remain stationary, wooden wedges or poles cut
from trees are driven in between the timbers and the vein and the hanging
wall and the footwall; and the space which remains empty is filled with loose
dirt. If the hanging and footwall rock is sometimes hard and sometimes soft,
and the vein likewise, solid joined timbers are not used, but timbers are
placed at intervals; and where the rock is soft and the vein crumbling,
carpenters put in lagging between them and the wall rocks, and behind these
they fill with loose dirt; by this means they fill up the void.
When a very deep shaft, whether vertical or inclined, is supported by
joined timbers, then, since they are sometimes of bad material and a fall is
threatened, for the sake of greater firmness three or four pairs of strong end
posts are placed between these, one pair on the hangingwall side, the other
on the footwall side. To prevent them from falling out of position and to
make them firm and substantial, they are supported by frequent end plates,
and in order that these may be more securely fixed they are mortised into
the posts. Further, in whatever way the shaft may be timbered, dividers
are placed upon the wall plates, and to these is fixed lagging, and this
marks off and separates the ladder−way from the remaining part of the shaft.
If a vertical shaft is a very deep one, planks are laid upon the timbers by the
side of the ladders and fixed on to the timbers, in order that the men who are
going up or down may sit or stand upon them and rest when they are tired.
To prevent danger to the shovellers from rocks which, after being drawn up
from so deep a shaft fall down again, a little above the bottom of the shaft
small rough sticks are placed close together on the timbers, in such a way as
to cover the whole space of the shaft except the ladder−way. A hole,
however, is left in this structure near the footwall, which is kept open so that
there may be one opening to the shaft from the bottom, that the buckets
full of the materials which have been dug out may be drawn from the
shaft through it by machines, and may be returned to the same place again
empty; and so the shovellers and other workmen, as it were hiding beneath
this structure, remain perfectly safe in the shaft.

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In mines on one vein there are driven one, two, or sometimes three
or more tunnels, always one above the other. If the vein is solid and
hard, and likewise the hanging and footwall rock, no part of the tunnel
needs support, beyond that which is required at the mouth, because at that
spot there is not yet solid rock; if the vein is soft, and the hanging and
footwall rock are likewise soft, the tunnel requires frequent strong timbering,
which is provided in the following way. First, two dressed posts are erected
and set into the tunnel floor, which is dug out a little; these are of medium

[219]
thickness, and high enough that their ends, which are cut square, almost
touch the top of the tunnel; then upon them is placed a smaller dressed cap,
which is mortised into the heads of the posts: at the bottom, other small
timbers, whose ends are similarly squared, are mortised into the posts. At
each interval of one and a half fathoms, one of these sets is erected; each one
of these the miners call a "little doorway," because it opens a certain amount
of passage way; and indeed, when necessity requires it, doors are fixed to the
timbers of each little doorway so that it can be closed. Then lagging of
planks or of poles is placed upon the caps lengthwise, so as to reach from one
set of timbers to another, and is laid along the sides, in case some portion of
the body of the mountain may fall, and by its bulk impede passage or crush
persons coming in or out. Moreover, to make the timbers remain stationary,
wooden pegs are driven between them and the sides of the tunnel. Lastly,
if rock or earth are carried out in wheelbarrows, planks joined together are
laid upon the sills; if the rock is hauled out in trucks, then two timbers
three−quarters of a foot thick and wide are laid on the sills, and, where they
join, these are usually hollowed out so that in the hollow, as in a road, the iron
pin of the truck may be pushed along; indeed, because of this pin in the
groove, the truck does not leave the worn track to the left or right. Beneath
the sills are the drains through which the water flows away.
APOSTS. BCAPS. CSILLS. DDOORS. ELAGGING. FDRAINS.
Miners timber drifts in the same way as tunnels. These do not, however,
require sill−pieces, or drains; for the broken rock is not hauled very far, nor does
the water have far to flow. If the vein above is metal−bearing, as it sometimes is

[220]
for a distance of several fathoms, then from the upper part of tunnels or even
drifts that have already been driven, other drifts are driven again
and again until that part of the vein is reached which does not yield metal.
The timbering of these openings is done as follows: stulls are set at
intervals into hitches in the hanging and footwall, and upon them
smooth poles are laid continuously; and that they may be able to
bear the weight, the stulls are generally a foot and a half thick. After the
ore has been taken out and the mining of the vein is being done elsewhere,
the rock then broken, especially if it cannot be taken away without great
difficulty, is thrown into these openings among the timber, and the carriers
of the ore are saved toil, and the owners save half the expense. This then,
generally speaking, is the method by which everything relating to the
timbering of shafts, tunnels, and drifts is carried out.
All that I have hitherto written is in part peculiar to venae profundae,
and in part common to all kinds of veins; of what follows, part is specially
applicable to venae dilatatae, part to venae cumulatae. But first I will
describe how venae dilatatae should be mined. Where torrents, rivers, or
streams have by inundations washed away part of the slope of a mountain or
a hill, and have disclosed a vena dilatata, a tunnel should be driven first straight
and narrow, and then wider, for nearly all the vein should be hewn away; and
when this tunnel has been driven further, a shaft which supplies air should be
sunk in the mountain or hill, and through it from time to time the ore, earth,
and rock can be drawn up at less expense than if they be drawn out through the
very great length of the tunnel; and even in those places to which the tunnel
does not yet reach, miners dig shafts in order to open a vena dilatata which
they conjecture must lie beneath the soil. In this way, when the upper
layers are removed, they dig through rock sometimes of one kind and colour,
sometimes of one kind but different colours, sometimes of different kinds but
of one colour, and, lastly, of different kinds and different colours. The thickness
of rock, both of each single stratum and of all combined, is uncertain, for
the whole of the strata are in some places twenty fathoms deep, in others
more than fifty; individual strata are in some places half a foot thick; in others,
one, two, or more feet; in others, one, two, three, or more fathoms. For
example, in those districts which lie at the foot of the Harz mountains,
there are many different coloured strata, covering a copper vena dilatata.
When the soil has been stripped, first of all is disclosed a stratum which
is red, but of a dull shade and of a thickness of twenty, thirty, or five and
thirty fathoms. Then there is another stratum, also red, but of a light
shade, which has usually a thickness of about two fathoms. Beneath this is a

[221]
stratum of ash−coloured clay nearly a fathom thick, which, although it is
not metalliferous, is reckoned a vein. Then follows a third stratum,
which is ashy, and about three fathoms thick. Beneath this lies a vein
of ashes to the thickness of five fathoms, and these ashes are mixed with
rock of the same colour. Joined to the last, and underneath, comes a
stratum, the fourth in number, dark in colour and a foot thick. Under this
comes the fifth stratum, of a pale or yellowish colour, two feet thick; under−

[222]
neath which is the sixth stratum, likewise dark, but rough and three feet
thick. Afterward occurs the seventh stratum, likewise of dark colour, but
still darker than the last, and two feet thick. This is followed by an eighth
stratum, ashy, rough, and a foot thick. This kind, as also the others,
is sometimes distinguished by stringers of the stone which easily melts in
fire of the second order. Beneath this is another ashy rock, light in
weight, and five feet thick. Next to this comes a lighter ash−coloured
one, a foot thick; beneath this lies the eleventh stratum, which is dark and
very much like the seventh, and two feet thick. Below the last is
a twelfth stratum of a whitish colour and soft, also two feet thick; the
weight of this rests on a thirteenth stratum, ashy and one foot thick, whose
weight is in turn supported by a fourteenth stratum, which is blackish and
half a foot thick. There follows this, another stratum of black colour,
likewise half a foot thick, which is again followed by a sixteenth stratum
still blacker in colour, whose thickness is also the same. Beneath this, and
last of all, lies the cupriferous stratum, black coloured and schistose, in which
there sometimes glitter scales of gold−coloured pyrites in the very thin sheets,
which, as I said elsewhere, often take the forms of various living things. 15
The miners mine out a vena dílatata laterally and longitudinally by
driving a low tunnel in it, and if the nature of the work and place permit, they
sink also a shaft in order to discover whether there is a second vein beneath
the first one; for sometimes beneath it there are two, three, or more similar
metal−bearing veins, and these are excavated in the same way laterally and
longitudinally. They generally mine venæ dilatatæ lying down; and to

[223]
avoid wearing away their clothes and injuring their left shoulders they
usually bind on themselves small wooden cradles. For this reason, this
particular class of miners, in order to use their iron tools, are obliged to bend
their necks to the left, not infrequently having them twisted. Now these
veins also sometimes divide, and where these parts re−unite, ore of a richer and
a better quality is generally found; the same thing occurs where the stringers,
of which they are not altogether devoid, join with them, or cut them crosswise,
or divide them obliquely. To prevent a mountain or hill, which has in
this way been undermined, from subsiding by its weight, either some natural
pillars and arches are left, on which the pressure rests as on a foundation, or
timbering is done for support. Moreover, the materials which are dug out
and which are devoid of metal are removed in bowls, and are thrown back,
thus once more filling the caverns.
Next, as to venæ cumulatæ. These are dug by a somewhat different
method, for when one of these shows some metal at the top of the ground,
first of all one shaft is sunk; then, if it is worth while, around this one many
shafts are sunk and tunnels are driven into the mountain. If a torrent or
spring has torn fragments of metal from such a vein, a tunnel is first driven
into the mountain or hill for the purpose of searching for the ore; then
when it is found, a vertical shaft is sunk in it. Since the whole mountain, or
more especially the whole hill, is undermined, seeing that the whole of it is
composed of ore, it is necessary to leave the natural pillars and arches, or the
place is timbered. But sometimes when a vein is very hard it is broken by
fire, whereby it happens that the soft pillars break up, or the timbers are
burnt away, and the mountain by its great weight sinks into itself, and then
the shaft buildings are swallowed up in the great subsidence. Therefore,
about a vena cumulata it is advisable to sink some shafts which are not sub−
ject to this kind of ruin, through which the materials that are excavated may
be carried out, not only while the pillars and underpinnings still remain whole
and solid, but also after the supports have been destroyed by fire and have
fallen. Since ore which has thus fallen must necessarily be broken by fire,
new shafts through which the smoke can escape must be sunk in the abyss.
At those places where stringers intersect, richer ore is generally obtained
from the mine; these stringers, in the case of tin mines, sometimes have in
them black stones the size of a walnut. If such a vein is found in a plain,
as not infrequently happens in the case of iron, many shafts are sunk, because
they cannot be sunk very deep. The work is carried on by this method
because the miners cannot drive a tunnel into a level plain of this kind.

[224]
There remain the stringers in which gold alone is sometimes found,
in the vicinity of rivers and streams, or in swamps. If upon the soil being
removed, many of these are found, composed of earth somewhat baked and
burnt, as may sometimes be seen in clay pits, there is some hope that gold
may be obtained from them, especially if several join together. But the
very point of junction must be pierced, and the length and width searched
for ore, and in these places very deep shafts cannot be sunk.
I have completed one part of this book, and now come to the other, in
which I will deal with the art of surveying. Miners measure the solid

[225]
mass of the mountains in order that the owners may lay out their plans, and
that their workmen may not encroach on other people' s possessions. The
surveyor either measures the interval not yet wholly dug through, which
lies between the mouth of a tunnel and a shaft to be sunk to that depth, or
between the mouth of a shaft and the tunnel to be driven to that spot which
lies under the shaft, or between both, if the tunnel is neither so long as to
reach to the shaft, nor the shaft so deep as to reach to the tunnel; and thus
on both sides work is still to be done. Or in some cases, within the tunnels
and drifts, are to be fixed the boundaries of the meers, just as the Bergmeister
has determined the boundaries of the same meers above ground. 16
Each method of surveying depends on the measuring of triangles. A
small triangle should be laid out, and from it calculations must be made
regarding a larger one. Most particular care must be taken that we do not
deviate at all from a correct measuring; for if, at the beginning, we are drawn

[226]
by carelessness into a slight error, this at the end will produce great errors.
Now these triangles are of many shapes, since shafts differ among themselves
and are not all sunk by one and the same method into the depths of the
earth, nor do the slopes of all mountains come down to the valley or plain in
the same manner. For if a shaft is vertical, there is a triangle with a right
angle, which the Greeks call o)rqogw/nion and this, according to the
inequalities of the mountain slope, has either two equal sides or three unequal
sides. The Greeks call the former tri/gwnon i)soskele/s the latter skalhno/n for
a right angle triangle cannot have three equal sides. If a shaft is inclined
and sunk in the same vein in which the tunnel is driven, a triangle is likewise
made with a right angle, and this again, according to the various inequalities
of the mountain slope, has either two equal or three unequal sides. But if
a shaft is inclined and is sunk in one vein, and a tunnel is driven in
another vein, then a triangle comes into existence which has either an obtuse
angle or all acute angles. The former the Greeks call a)mblugw/nion, the latter
o)xugw/nion. That triangle which has an obtuse angle cannot have three
equal sides, but in accordance with the different mountain slopes has either
two equal sides or three unequal sides. That triangle which has all acute
angles in accordance with the different mountain slopes has either three equal
sides, which the Greeks call tri/gwnon i)so/pleuron or two equal sides or three
unequal sides.
The surveyor, as I said, employs his art when the owners of the mines
desire to know how many fathoms of the intervening ground require to be
dug; when a tunnel is being driven toward a shaft and does not yet reach
it; or when the shaft has not yet been sunk to the depth of the bottom of the
tunnel which is under it; or when neither the tunnel reaches to that point,
nor has the shaft been sunk to it. It is of importance that miners should
know how many fathoms remain from the tunnel to the shaft, or from the
shaft to the tunnel, in order to calculate the expenditure; and in order that
the owners of a metal−bearing mine may hasten the sinking of a shaft and
the excavation of the metal, before the tunnel reaches that point and the
tunnel owners excavate part of the metal by any right of their own; and on
the other hand, it is important that the owners of a tunnel may similarly
hasten their driving before a shaft can be sunk to the depth of a tunnel, so
that they may excavate the metal to which they will have a right.
The surveyor, first of all, if the beams of the shaft−house do not give him
the opportunity, sets a pair of forked posts by the sides of the shaft in such
a manner that a pole may be laid across them. Next, from the pole he lets

[227]
down into the shaft a cord with a weight attached to it. Then he stretches a
second cord, attached to the upper end of the first cord, right down along the
slope of the mountain to the bottom of the mouth of the tunnel, and fixes it to
the ground. Next, from the same pole not far from the first cord, he lets
down a third cord, similarly weighted, so that it may intersect the second
cord, which descends obliquely. Then, starting from that point where the
third cord cuts the second cord which descends obliquely to the mouth of the
tunnel, he measures the second cord upward to where it reaches the end of

[228]
AUPRIGHT FORKED POSTS. BPOLE OVER THE POSTS. CSHAFT. DFIRST CORD.
EWEIGHT OF FIRST CORD. FSECOND CORD. GSAME FIXED GROUND. HHEAD
OF FIRST CORD. IMOUTH OF TUNNEL. KTHIRD CORD. LWEIGHT OF THIRD CORD.
MFIRST SIDE MINOR TRIANGLE. NSECOND SIDE MINOR TRIANGLE. OTHIRD SIDE
MINOR TRIANGLE. PTHE MINOR TRIANGLE.
1
[229]
the first cord, and makes a note of this first side of the minor triangle 17 .
Afterward, starting again from that point where the third cord intersects the
second cord, he measures the straight space which lies between that point
and the opposite point on the first cord, and in that way forms the minor
triangle, and he notes this second side of the minor triangle in the same way as
before. Then, if it is necessary, from the angle formed by the first cord and
the second side of the minor triangle, he measures upward to the end of the
first cord and also makes a note of this third side of the minor triangle. The
third side of the minor triangle, if the shaft is vertical or inclined and is sunk
on the same vein in which the tunnel is driven, will necessarily be the same
length as the third cord above the point where it intersects the second cord;
and so, as often as the first side of the minor triangle is contained in the
length of the whole cord which descends obliquely, so many times the length
of the second side of the minor triangle indicates the distance between the
mouth of the tunnel and the point to which the shaft must be sunk; and
similarly, so many times the length of the third side of the minor triangle
gives the distance between the mouth of the shaft and the bottom of the
tunnel.
When there is a level bench on the mountain slope, the surveyor first
measures across this with a measuring−rod; then at the edges of this bench
he sets up forked posts, and applies the principle of the triangle to the two
sloping parts of the mountain; and to the fathoms which are the length of
that part of the tunnel determined by the triangles, he adds the number
of fathoms which are the width of the bench. But if sometimes the
mountain side stands up, so that a cord cannot run down from the shaft to
the mouth of the tunnel, or, on the other hand, cannot run up from the
mouth of the tunnel to the shaft, and, therefore, one cannot connect them in
a straight line, the surveyor, in order to fix an accurate triangle, measures the
mountain; and going downward he substitutes for the first part of the cord
a pole one fathom long, and for the second part a pole half a fathom
long. Going upward, on the contrary, for the first part of the cord he sub−
stitutes a pole half a fathom long, and for the next part, one a whole fathom
long; then where he requires to fix his triangle he adds a straight line to
these angles.
To make this system of measuring clear and more explicit, I will proceed
by describing each separate kind of triangle. When a shaft is vertical or
inclined, and is sunk in the same vein on which the tunnel is driven, there
is created, as I said, a triangle containing a right angle. Now if the minor

[230]
triangle has the two sides equal, which, in accordance with the numbering
used by surveyors, are the second and third sides, then the second and third
sides of the major triangle will be equal; and so also the intervening
distances will be equal which lie between the mouth of the tunnel and the
bottom of the shaft, and which lie between the mouth of the shaft and the
bottom of the tunnel. For example, if the first side of the minor triangle is
seven feet long and the second and likewise the third sides are five feet, and

[231]
the length shown by the cord for the side of the major triangle is 101 times
seven feet, that is 117 fathoms and five feet, then the intervening space, of
course, whether the whole of it has been already driven through or has yet
to be driven, will be one hundred times five feet, which makes eighty−three
fathoms and two feet. Anyone with this example of proportions will be
able to construct the major and minor triangles in the same way as I have
done, if there be the necessary upright posts and cross−beams. When a shaft is
vertical the triangle is absolutely upright; when it is inclined and is sunk on
the same vein in which the tunnel is driven, it is inclined toward one side.
A TRIANGLE HAVING A RIGHT ANGLE AND TWO EQUAL SIDES.
Therefore, if a tunnel has been driven into the mountain for sixty fathoms,
there remains a space of ground to be penetrated twenty−three fathoms and
two feet long; for five feet of the second side of the major triangle, which
lies above the mouth of the shaft and corresponds with the first side of the
minor triangle, must not be added. Therefore, if the shaft has been sunk
in the middle of the head meer, a tunnel sixty fathoms long will reach
to the boundary of the meer only when the tunnel has been extended a
further two fathoms and two feet; but if the shaft is located in the middle of
an ordinary meer, then the boundary will be reached when the tunnel has been
driven a further length of nine fathoms and two feet. Since a tunnel, for
every one hundred fathoms of length, rises in grade one fathom, or at all
events, ought to rise as it proceeds toward the shaft, one more fathom must
always be taken from the depth allowed to the shaft, and one added to the
length allowed to the tunnel. Proportionately, because a tunnel fifty
fathoms long is raised half a fathom, this amount must be taken from the
depth of the shaft and added to the length of the tunnel. In the same way
if a tunnel is one hundred or fifty fathoms shorter or longer, the same propor−
tion also must be taken from the depth of the one and added to the length
of the other. For this reason, in the case mentioned above, half a fathom
and a little more must be added to the distance to be driven through, so
that there remain twenty−three fathoms, five feet, two palms, one and a half
digits and a fifth of a digit; that is, if even the minutest proportions are
carried out; and surveyors do not neglect these without good cause.
Similarly, if the shaft is seventy fathoms deep, in order that it may reach to
the bottom of the tunnel, it still must be sunk a further depth of thirteen
fathoms and two feet, or rather twelve fathoms and a half, one foot, two
digits, and four−fifths of half a digit. And in this instance five feet must be
deducted from the reckoning, because these five feet complete the third side
of the minor triangle, which is above the mouth of the shaft, and from its

[232]
depth there must be deducted half a fathom, two palms, one and a half digits
and the fifth part of half a digit. But if the tunnel has been driven to a
point where it is under the shaft, then to reach the roof of the tunnel the
shaft must still be sunk a depth of eleven fathoms, two and a half feet, one
palm, two digits, and four−fifths of half a digit.
If a minor triangle is produced of the kind having three unequal sides,
then the sides of the greater triangle cannot be equal; that is, if the first
side of the minor triangle is eight feet long, the second six feet long, and the
third five feet long, and the cord along the side of the greater triangle, not
to go too far from the example just given, is one hundred and one times
eight feet, that is, one hundred and thirty−four fathoms and four feet, the
distance which lies between the mouth of the tunnel and the bottom of the
shaft will occupy one hundred times six feet in length, that is, one hundred
fathoms. The distance between the mouth of the shaft and the bottom of the
tunnel is one hundred times five feet, that is, eighty−three fathoms and two feet.
And so, if the tunnel is eighty−five fathoms long, the remainder to be driven
into the mountain is fifteen fathoms long, and here, too, a correction in
measurement must be taken from the depth of the shaft and added to the
length of the tunnel; what this is precisely, I will pursue no further, since
everyone having a small knowledge of arithmetic can work it out. If the
shaft is sixty−seven fathoms deep, in order that it may reach the bottom of
the tunnel, the further distance required to be sunk amounts to sixteen
fathoms and two feet.
A TRIANGLE HAVING A RIGHT ANGLE AND THREE UNEQUAL SIDES.
The surveyor employs this same method in measuring the mountain,
whether the shaft and tunnel are on one and the same vein, whether the vein
is vertical or inclined, or whether the shaft is on the principal vein and the tunnel
on a transverse vein descending vertically to the depths of the earth; in the
latter case the excavation is to be made where the transverse vein cuts the
vertical vein. If the principal vein descends on an incline and the cross−vein
descends vertically, then a minor triangle is created having one obtuse angle or
all three angles acute. If the minor triangle has one angle obtuse and the two
sides which are the second and third are equal, then the second and third
sides of the major triangle will be equal, so that if the first side of the minor
triangle is nine feet, the second, and likewise the third, will be five feet. Then
the first side of the major triangle will be one hundred and one times nine
feet, or one hundred and fifty−one and one−half fathoms, and each of the

[233]
other sides of the major triangle will be one hundred times five feet, that is,
eighty−three fathoms and two feet. But when the first shaft is inclined,

[234]
generally speaking, it is not deep; but there are usually several, all
inclined, and one always following the other. Therefore, if a tunnel is seventy−
seven fathoms long, it will reach to the middle of the bottom of a shaft when
six fathoms and two feet further have been sunk. But if all such inclined
shafts are seventy−six fathoms deep, in order that the last one may reach
the bottom of the tunnel, a depth of seven fathoms and two feet remains to
be sunk.
TRIANGLE HAVING AN OBTUSE ANGLE AND TWO EQUAL SIDES.
If a minor triangle is made which has an obtuse angle and three unequal
sides, then again the sides of the large triangle cannot be equal. For
example, if the first side of the minor triangle is six feet long, the second
three feet, and the third four feet, and the cord along the side of the greater
triangle one hundred and one times six feet, that is, one hundred and one
fathoms, the distance between the mouth of the tunnel and the bottom of
the last shaft will be a length one hundred times three feet, or fifty fathoms;
but the depth that lies between the mouth of the first shaft and the bottom of
the tunnel is one hundred times four feet, or sixty−six fathoms and four feet.
Therefore, if a tunnel is forty−four fathoms long, the remaining distance to
be driven is six fathoms. If the shafts are fifty−eight fathoms deep, the
newest will touch the bottom of the tunnel when eight fathoms and four
feet have been sunk.
TRIANGLE HAVING AN OBTUSE ANGLE AND THREE UNEQUAL SIDES.
If a minor triangle is produced which has all its angles acute and its
three sides equal, then necessarily the second and third sides of the minor
triangle will be equal, and likewise the sides of the major triangle frequently
referred to will be equal. Thus if each side of the minor triangle is six feet
long, and the cord measurement for the side of the major triangle is one
hundred and one times six feet, that is, one hundred and one fathoms, then
both the distances to be dug will be one hundred fathoms. And thus if the
tunnel is ninety fathoms long, it will reach the middle of the bottom of the
last shaft when ten fathoms further have been driven. If the shafts are

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ninety−five fathoms deep, the last will reach the bottom of the tunnel when
it is sunk a further depth of five fathoms.
A TRIANGLE HAVING ALL ITS ANGLES ACUTE AND ITS THREE SIDES EQUAL.
If a triangle is made which has all its angles acute, but only two sides
equal, namely, the first and third, then the second and third sides are not
equal; therefore the distances to be dug cannot be equal. For example, if
the first side of the minor triangle is six feet long, and the second is four feet,
and the third is six feet, and the cord measurement for the side of the major
triangle is one hundred and one times six feet, that is, one hundred and one
fathoms, then the distance between the mouth of the tunnel and the bottom of
the last shaft will be sixty−six fathoms and four feet. But the distance from the
mouth of the first shaft to the bottom of the tunnel is one hundred fathoms.
So if the tunnel is sixty fathoms long, the remaining distance to be driven
into the mountain is six fathoms and four feet. If the shaft is ninety−seven
fathoms deep, the last one will reach the bottom of the tunnel when a further
depth of three fathoms has been sunk.
TRIANGLE HAVING ALL ITS ANGLES ACUTE AND TWO SIDES EQUAL, A, B, UNEQUAL SIDE C.
If a minor triangle is produced which has all its angles acute, but its
three sides unequal, then again the distances to be dug cannot be equal.
For example, if the first side of the minor triangle is seven feet long, the
second side is four feet, and the third side is six feet, and the cord measure−
ment for the side of the major triangle is one hundred and one times seven
feet or one hundred and seventeen fathoms and four feet, the distance
between the mouth of the tunnel and the bottom of the last shaft will be
four hundred feet or sixty−six fathoms, and the depth between the mouth of
the first shaft and the bottom of the tunnel will be one hundred fathoms.
Therefore, if a tunnel is fifty fathoms long, it will reach the middle of the
bottom of the newest shaft when it has been driven sixteen fathoms and four
feet further. But if the shafts are then ninety−two fathoms deep, the last

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shaft will reach the bottom of the tunnel when it has been sunk a further
eight fathoms.
A TRIANGLE HAVING ALL ITS ANGLES ACUTE AND ITS THREE SIDES UNEQUAL.
This is the method of the surveyor in measuring the mountain, if the
principal vein descends inclined into the depths of the earth or the transverse
vein is vertical. But if they are both inclined, the surveyor uses the same
method, or he measures the slope of the mountain separately from the slope
of the shaft. Next, if a transverse vein in which a tunnel is driven does not
cut the principal vein in that spot where the shaft is sunk, then it is necessary
for the starting point of the survey to be in the other shaft in which the
transverse vein cuts the principal vein. But if there be no shaft on that spot
where the outcrop of the transverse vein cuts the outcrop of the principal
vein, then the surface of the ground which lies between the shafts must
be measured, or that between the shaft and the place where the outcrop of
the one vein intersects the outcrop of the other.
Some surveyors, although they use three cords, nevertheless ascertain
only the length of a tunnel by that method of measuring, and determine
the depth of a shaft by another method; that is, by the method by
which cords are re−stretched on a level part of the mountain or in
a valley, or in flat fields, and are measured again. Some, however, do
not employ this method in surveying the depth of a shaft and the
length of a tunnel, but use only two cords, a graduated hemicycle 18 and a
rod half a fathom long. They suspend in the shaft one cord, fastened
from the upper pole and weighted, just as the others do. Fastened to the
upper end of this cord, they stretch another right down the slope of the mountain
to the bottom of the mouth of the tunnel and fix it to the ground. Then to
the upper part of this second cord they apply on its lower side the broad part
of a hemicycle. This consists of half a circle, the outer margin of which is
covered with wax, and within this are six semi−circular lines. From the

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waxed margin through the first semi−circular line, and reaching to the second,
there proceed straight lines converging toward the centre of the hemicycle;
these mark the middles of intervening spaces lying between other straight lines
which extend to the fourth semi−circular line. But all lines whatsoever, from
the waxed margin up to the fourth line, whether they go beyond it or not,
correspond with the graduated lines which mark the minor spaces of a rod.
Those which go beyond the fourth line correspond with the lines marking
AWAXED SEMICIRCLE OF THE HEMICYCLE. BSEMICIRCULAR LINES. CSTRAIGHT
LINES. DLINE MEASURING THE HALF. ELINE MEASURING THE WHOLE. FTONGUE.

238
the major spaces on the rod, and those which proceed further, mark the
middle of the intervening space which lies between the others. The
straight lines, which run from the fifth to the sixth semi−circular line, show
nothing further. Nor does the line which measures the half, show anything
when it has already passed from the sixth straight line to the base of the
hemicycle. When the hemicycle is applied to the cord, if its tongue indicates
the sixth straight line which lies between the second and third semi−circular
lines, the surveyor counts on the rod six lines which separate the minor
spaces, and if the length of this portion of the rod be taken from the second
cord, as many times as the cord itself is half−fathoms long, the remaining
length of cord shows the distance the tunnel must be driven to reach under
the shaft. But if he sees that the tongue has gone so far that it marks the
sixth line between the fourth and fifth semi−circular lines, he counts six lines
which separate the major spaces on the rod; and this entire space is deducted
from the length of the second cord, as many times as the number of whole
fathoms which the cord contains; and then, in like manner, the remaining
length of cord shows us the distance the tunnel must be driven to reach
under the shaft. 19
STRETCHED CORDS: AFIRST CORD. BSECOND CORD. CTHIRD CORD.
DTRIANGLE.
1
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Both these surveyors, as well as the others, in the first place make use
of the haulage rope. These they measure by means of others made of linden
bark, because the latter do not stretch at all, while the former become very
slack. These cords they stretch on the surveyor' s field, the first one to
represent the parts of mountain slopes which descend obliquely. Then the
second cord, which represents the length of the tunnel to be driven to reach
the shaft, they place straight, in such a direction that one end of it can touch
the lower end of the first cord; then they similarly lay the third cord straight,
and in such a direction that its upper end may touch the upper end of
the first cord, and its lower end the other extremity of the second cord, and
thus a triangle is formed. This third cord is measured by the instrument
with the index, to determine its relation to the perpendicular; and the length
of this cord shows the depth of the shaft.
Some surveyors, to make their system of measuring the depth of a shaft
more certain, use five stretched cords: the first one descending obliquely;
two, that is to say the second and third, for ascertaining the length of the
tunnel; two for the depth of the shaft; in which way they form a quadrangle
divided into two equal triangles, and this tends to greater accuracy.
STRETCHED CORDS: AFIRST. BSECOND. BTHIRD. CFOURTH. CFIFTH.
DQUADRANGLE.
These systems of measuring the depth of a shaft and the length of a
tunnel, are accurate when the vein and also the shaft or shafts go down to the

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tunnel vertically or inclined, in an uninterrupted c se. The same is true
when a tunnel runs straight on to a shaft. But when each of them bends
now in this, now in that direction, if they have not been completely driven
and sunk, no living man is clever enough to judge how far they are deflected
from a straight course. But if the whole of either one of the two has been ex−
cavated its full distance, then we can estimate more easily the length of one,
or the depth of the other; and so the location of the tunnel, which is below
a newly−started shaft, is determined by a method of surveying which I will
describe. First of all a tripod is fixed at the mouth of the tunnel, and likewise at
the mouth of the shaft which has been started, or at the place where the shaft will
be started. The tripod is made of three stakes fixed to the ground, a small
rectangular board being placed upon the stakes and fixed to them, and on
this is set a compass. Then from the lower tripod a weighted cord is let
down perpendicularly to the earth, close to which cord a stake is fixed in the
ground. To this stake another cord is tied and drawn straight into the tunnel
to a point as far as it can go without being bent by the hangingwall or the
footwall of the vein. Next, from the cord which hangs from the lower tripod,
a third cord likewise fixed is brought straight up the sloping side of the
mountain to the stake of the upper tripod, and fastened to it. In order that
the measuring of the depth of the shaft may be more certain, the third cord
should touch one and the same side of the cord hanging from the lower tripod
which is touched by the second cordthe one which is drawn into the tunnel.
All this having been correctly carried out, the surveyor, when at length
the cord which has been drawn straight into the tunnel is about to be bent
by the hangingwall or footwall, places a plank in the bottom of the tunnel
and on it sets the orbis, an instrument which has an indicator peculiar
to itself. This instrument, although it also has waxed circles, differs from the
other, which I have described in the third book. But by both these
instruments, as well as by a rule and a square, he determines whether the
stretched cords reach straight to the extreme end of the tunnel, or whether
they sometimes reach straight, and are sometimes bent by the footwall or
hangingwall. Each instrument is divided into parts, but the compass into
twenty−four parts, the orbis into sixteen parts; for first of all it is divided
into four principal parts, and then each of these is again divided into four.
Both have waxed circles, but the compass has seven circles, and the orbis
only five circles. These waxed circles the surveyor marks, whichever instru−
ment he uses, and by the succession of these same marks he notes any
change in the direction in which the cord extends. The orbis has an open−
ing running from its outer edge as far as the centre, into which opening he
puts an iron screw, to which he binds the second cord, and by screwing it into

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the plank, fixes it so that the orbis may be immovable. He takes care
to prevent the second cord, and afterward the others which are put up,
from being pulled off the screw, by employing a heavy iron, into an opening
of which he fixes the head of the screw. In the case of the compass, since
it has no opening, he merely places it by the side of the screw. That the
instrument does not incline forward or backward, and in that way the
1
242
measurement become a greater length than it should be, he sets upon the
instrument a standing plummet level, the tongue of which, if the instrument
is level, indicates no numbers, but the point from which the numbers start.
COMPASS. A, B, C, D, E, F, G ARE THE SEVEN WAXED CIRCLES.
When the surveyor has carefully observed each separate angle of the
tunnel and has measured such parts as he ought to measure, then he lays
them out in the same way on the surveyor' s field 20 in the open air, and again
no less carefully observes each separate angle and measures them. First of
all, to each angle, according as the calculation of his triangle and his art
require it, he lays out a straight cord as a line. Then he stretches a cord at
1
243
A, B, C, D, EFIVE WAXED CIRCLES OF THE orbis.
FOPENING OF SAME. GSCREW. HPERFORATED IRON.

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ALINES OF THE ROD WHICH SEPARATE MINOR SPACES. BLINES OF THE ROD WHICH
SEPARATE MAJOR SPACES.

[245]
such an angle as represents the slope of the mountain, so that its lower end
may reach the end of the straight cord; then he stretches a third cord
ASTANDING PLUMMET LEVEL. BTONGUE. CLEVEL AND TONGUE.

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similarly straight and at such an angle, that with its upper end it may reach
the upper end of the second cord, and with its lower end the last end of the
first cord. The length of the third cord shows the depth of the shaft, as I
said before, and at the same time that point on the tunnel to which the shaft
will reach when it has been sunk.
If one or more shafts reach the tunnel through intermediate drifts and
shafts, the surveyor, starting from the nearest which is open to the air,
measures in a shorter time the depth of the shaft which requires to be sunk,
than if he starts from the mouth of the tunnel. First of all he measures
that space on the surface which lies between the shaft which has been sunk
and the one which requires to be sunk. Then he measures the incline of all
the shafts which it is necessary to measure, and the length of all the drifts
with which they are in any way connected to the tunnel. Lastly, he
measures part of the tunnel; and when all this is properly done, he demon−
strates the depth of the shaft and the point in the tunnel to which the shaft
will reach. But sometimes a very deep straight shaft requires to be sunk
at the same place where there is a previous inclined shaft, and to the same
depth, in order that loads may be raised and drawn straight up by machines.
Those machines on the surface are turned by horses; those inside the earth,
by the same means, and also by water−power. And so, if it becomes
necessary to sink such a shaft, the surveyor first of all fixes an iron screw
in the upper part of the old shaft, and from the screw he lets down a cord
as far as the first angle, where again he fixes a screw, and again lets down the
cord as far as the second angle; this he repeats again and again until the
cord reaches to the bottom of the shaft. Then to each angle of the cord he
applies a hemicycle, and marks the waxed semi−circle according to the lines
which the tongue indicates, and designates it by a number, in case it should be
moved; then he measures the separate parts of the cord with another cord
made of linden bark. Afterward, when he has come back out of the shaft,
he goes away and transfers the markings from the waxed semi−circle of the
hemicycle to an orbis similarly waxed. Lastly, the cords are stretched on the
surveyor' s field, and he measures the angles, as the system of measuring by
triangles requires, and ascertains which part of the footwall and which
part of the hangingwall rock must be cut away in order that the shaft may
descend straight. But if the surveyor is required to show the owners of the
mine, the spot in a drift or a tunnel in which a shaft needs to be raised
from the bottom upward, that it should cut through more quickly, he
begins measuring from the bottom of the drift or tunnel, at a point
beyond the spot at which the bottom of the shaft will arrive, when it has been

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sunk. When he has measured the part of the drift or tunnel up to the first
shaft which connects with an upper drift, he measures the incline of this
shaft by applying a hemicycle or orbis to the cord. Then in a like manner
he measures the upper drift and the incline shaft which is sunk therein
toward which a raise is being dug, then again all the cords are stretched in
the surveyor' s field, the last cord in such a way that it reaches the first, and
then he measures them. From this measurement is known in what part

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of the drift or tunnel the raise should be made, and how many fathoms of
vein remain to be broken through in order that the shaft may be connected.
I have described the first reason for surveying; I will now describe
another. When one vein comes near another, and their owners are different
persons who have late come into possession, whether they drive a tunnel
or a drift, or sink a shaft, they may encroach, or seem to encroach, without
any lawful right, upon the boundaries of the older owners, for which reason
the latter very often seek redress, or take legal proceedings. The surveyor
either himself settles the dispute between the owners, or by his art gives
evidence to the judges for making their decision, that one shall not encroach
on the mine of the other. Thus, first of all he measures the mines of each
party with a basket rope and cords of linden bark; and having applied to the
cords an orbis or a compass, he notes the directions in which they extend.
Then he stretches the cords on the surveyor' s field; and starting from that
point whose owners are in possession of the old meer toward the other,
whether it is in the hanging or footwall of the vein, he stretches a cross−
cord in a straight line, according to the sixth division of the compass,
that is, at a right angle to the vein, for a distance of three and a
half fathoms, and assigns to the older owners that which belongs to
them. But if both ends of one vein are being dug out in two tunnels, or
drifts from opposite directions, the surveyor first of all considers the lower
tunnel or drift and afterward the upper one, and judges how much each of
them has risen little by little. On each side strong men take in their hands
a stretched cord and hold it so that there is no point where it is not strained
tight; on each side the surveyor supports the cord with a rod half a fathom
long, and stays the rod at the end with a short stick as often as he thinks
it necessary. But some fasten cords to the rods to make them steadier.
The surveyor attaches a suspended plummet level to the middle of the cord to
enable him to calculate more accurately on both sides, and from this he ascer−
tains whether one tunnel has risen more than another, or in like manner one
drift more than another. Afterward he measures the incline of the shafts
on both sides, so that he can estimate their position on each side. Then he
easily sees how many fathoms remain in the space which must be broken
through. But the grade of each tunnel, as I said, should rise one fathom in
the distance of one hundred fathoms.
The Swiss surveyors, when they wish to measure tunnels driven into
the highest mountains, also use a rod half a fathom long, but composed of
three parts, which screw together, so that they may be shortened. They

[249]
use a cord made of linden bark to which are fastened slips of paper showing
the number of fathoms. They also employ an instrument peculiar to them,
which has a needle; but in place of the waxed circles they carry in their
hands a chart on which they inscribe the readings of the instrument. The
instrument is placed on the back part of the rod so that the tongue, and the
extended cord which runs through the three holes in the tongue, demonstrates
the direction, and they note the number of fathoms. The tongue shows
whether the cord inclines forward or backward. The tongue does not hang,

[250]
as in the case of the suspended plummet level, but is fixed to the instrument in
a half−lying position. They measure the tunnels for the purpose of knowing
how many fathoms they have been increased in elevation; how many fathoms
the lower is distant from the upper one; how many fathoms of interval is
INDICATOR OF A SUSPENDED PLUMMET LEVEL.

[251]
not yet pierced between the miners who on opposite sides are digging on
the same vein, or cross−stringers, or two veins which are approaching one
another.
But I return to our mines. If the surveyor desires to fix the boundaries
of the meer within the tunnels or drifts, and mark to them with a sign cut in the
rock, in the same way that the Bergmeíster has marked these boundaries
above ground, he first of all ascertains, by measuring in the manner
which I have explained above, which part of the tunnel or drift lies
beneath the surface boundary mark, stretching the cords along the drifts to
a point beyond that spot in the rock where he judges the mark should be
cut. Then, after the same cords have been laid out on the surveyor' s field,
he starts from that upper cord at a point which shows the boundary mark,
and stretches another cross−cord straight downward according to the sixth
ANEEDLE OF THE INSTRUMENT. BITS TONGUE. C, D, EHOLES IN THE TONGUE.

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division of the compassthat is at a right angle. Then that part
of the lowest cord which lies beyond the part to which the cross−cord
runs being removed, it shows at what point the boundary mark should
be cut into the rock of the tunnel or drift. The cutting is made in the
presence of the two Jurors and the manager and the foreman of each
mine. For as the Bergmeíster in the presence of these same persons sets
the boundary stones on the surface, so the surveyor cuts in the rock a sign
which for this reason is called the boundary rock. If he fixes the boundary
mark of a meer in which a shaft has recently begun to be sunk on a vein,
first of all he measures and notes the incline of that shaft by the com−
pass or by another way with the applied cords; then he measures all
the drifts up to that one in whose rock the boundary mark has to
be cut. Of these drifts he measures each angle; then the cords, being
laid out on the surveyor' s field, in a similar way he stretches a cross−
cord, as I said, and cuts the sign on the rock. But if the underground
boundary rock has to be cut in a drift which lies beneath the first drift, the
surveyor starts from the mark in the first drift, notes the different angles,
one by one, takes his measurements, and in the lower drift stretches a cord
beyond that place where he judges the mark ought to be cut; and then,
as I said before, lays out the cords on the surveyor' s field. Even if a vein
runs differently in the lower drift from the upper one, in which the first
boundary mark has been cut in the rock, still, in the lower drift the mark
must be cut in the rock vertically beneath. For if he cuts the lower mark
obliquely from the upper one some part of the possession of one mine is
taken away to its detriment, and given to the other. Moreover, if it
happens that the underground boundary mark requires to be cut in an
angle, the surveyor, starting from that angle, measures one fathom toward
the front of the mine and another fathom toward the back, and from these
measurements forms a triangle, and dividing its middle by a cross−cord,
makes his cutting for the boundary mark.
Lastly, the surveyor sometimes, in order to make more certain, finds the
boundary of the meers in those places where many old boundary marks
are cut in the rock. Then, starting from a stake fixed on the surface,
he first of all measures to the nearest mine; then he measures one shaft
after another; then he fixes a stake on the surveyors' field, and making
a beginning from it stretches the same cords in the same way and measures
them, and again fixes in the ground a stake which for him will signify the end
of his measuring. Afterward he again measures underground from that
spot at which he left off, as many shafts and drifts as he can remember. Then

[253]
he returns to the surveyor' s field, and starting again from the second stake,
makes his measurements; and he does this as far as the drift in which the
boundary mark must be cut in the rock. Finally, commencing from the
stake first fixed in the ground, he stretches a cross−cord in a straight line to
the last stake, and this shows the length of the lowest drift. The point
where they touch, he judges to be the place where the underground boundary
mark should be cut.
END OF BOOK V.