[14] Fire-setting as an aid to breaking rock is of very ancient origin,
and moreover it persisted in certain German and Norwegian mines down to
the end of the 19th century--270 years after the first application of
explosives to mining. The first specific reference to fire-setting in
mining is by Agatharchides (2nd century B.C.) whose works are not
extant, but who is quoted by both Diodorus Siculus and Photius, for
which statement see note 8, p. 279. Pliny (XXXIII, 21) says:
"Occasionally a kind of silex is met with, which must be broken with
fire and vinegar, or as the tunnels are filled with suffocating fumes
and smoke, they frequently use bruising machines, carrying 150 _librae_
of iron." This combination of fire and vinegar he again refers to
(XXIII, 27), where he dilates in the same sentence on the usefulness of
vinegar for breaking rock and for salad dressing. This myth about
breaking rocks with fire and vinegar is of more than usual interest, and
its origin seems to be in the legend that Hannibal thus broke through
the Alps. Livy (59 B.C., 17 A.D.) seems to be the first to produce this
myth in writing; and, in any event, by Pliny's time (23-79 A.D.) it had
become an established method--in literature. Livy (XXI, 37) says, in
connection with Hannibal's crossing of the Alps: "They set fire to it
(the timber) when a wind had arisen suitable to excite the fire, then
when the rock was hot it was crumbled by pouring on vinegar (_infuso
aceto_). In this manner the cliff heated by the fire was broken by iron
tools, and the declivities eased by turnings, so that not only the
beasts of burden but also the elephants could be led down." Hannibal
crossed the Alps in 218 B.C. and Livy's account was written 200 years
later, by which time Hannibal's memory among the Romans was generally
surrounded by Herculean fables. Be this as it may, by Pliny's time the
vinegar was generally accepted, and has been ceaselessly debated ever
since. Nor has the myth ceased to grow, despite the remarks of Gibbon,
Lavalette, and others. A recent historian (Hennebert, _Histoire d'
Annibal_ II, p. 253) of that famous engineer and soldier, soberly sets
out to prove that inasmuch as literal acceptance of ordinary vinegar is
impossible, the Phoenicians must have possessed some mysterious high
explosive. A still more recent biographer swallows this argument _in
toto_. (Morris, "Hannibal," London, 1903, p. 103). A study of the
commentators of this passage, although it would fill a volume with
sterile words, would disclose one generalization: That the real scholars
have passed over the passage with the comment that it is either a
corruption or an old woman's tale, but that hosts of soldiers who set
about the biography of famous generals and campaigns, almost to a man
take the passage seriously, and seriously explain it by way of the rock
being limestone, or snow, or by the use of explosives, or other
foolishness. It has been proposed, although there are grammatical
objections, that the text is slightly corrupt and read _infosso acuto_,
instead of _infuso aceto_, in which case all becomes easy from a mining
point of view. If so, however, it must be assumed that the corruption
occurred during the 20 years between Livy and Pliny.
By the use of fire-setting in recent times at Koenigsberg (Arthur L.
Collins, "Fire-setting," Federated Inst. of Mining Engineers, Vol. V, p.
82) an advance of from 5 to 20 feet per month in headings was
accomplished, and on the score of economy survived the use of gunpowder,
but has now been abandoned in favour of dynamite. We may mention that
the use of gunpowder for blasting was first introduced at Schemnitz by
Caspar Weindle, in 1627, but apparently was not introduced into English
mines for nearly 75 years afterward, as the late 17th century English
writers continue to describe fire-setting.
[15] The strata here enumerated are given in the Glossary of _De Re
Metallica_ as follows:--
_Corium terrae_ _Die erd oder leim._
_Saxum rubrum_ _Rot gebirge._
_Alterum item rubrum_ _Roterkle._
_Argilla cinerea_ _Thone._
_Tertium saxum_ _Gerhulle._
_Cineris vena_ _Asche._
_Quartum saxum_ _Gniest._
_Quintum saxum_ _Schwehlen._
_Sextum saxum_ _Oberrauchstein._
_Septimum saxum_ _Zechstein._
_Octavum saxum_ _Underrauchstein._
_Nonum saxum_ _Blitterstein._
_Decimum saxum_ _Oberschuelen._
_Undecimum saxum_ _Mittelstein._
_Duodecimum saxum_ _Underschuelen._
_Decimumtertium saxum_ _Dach._
_Decimumquartum saxum_ _Norweg._
_Decimumquintum saxum_ _Lotwerg._
_Decimumsextum saxum_ _Kamme._
_Lapis aerosus fissilis_ _Schifer._
The description is no doubt that of the Mannsfeld cupriferous slates. It
is of some additional interest as the first attempt at stratigraphic
distinctions, although this must not be taken too literally, for we have
rendered the different numbered "_saxum_" in this connection as
"stratum." The German terms given by Agricola above, can many of them be
identified in the miners' terms to-day for the various strata at
Mannsfeld. Over the _kupferschiefer_ the names to-day are _kammschale_,
_dach_, _faule_, _zechstein_, _rauchwacke_, _rauchstein_, _asche_. The
relative thickness of these beds is much the same as given by Agricola.
The stringers in the 8th stratum of stone, which fuse in the fire of the
second order, were possibly calcite. The _rauchstein_ of the modern
section is distinguished by stringers of calcite, which give it at times
a brecciated appearance.
[16] The history of surveying and surveying instruments, and in a
subsidiary way their application to mine work, is a subject upon which
there exists a most extensive literature. However, that portion of such
history which relates to the period prior to Agricola represents a much
less proportion of the whole than do the citations to this chapter in
_De Re Metallica_, which is the first comprehensive discussion of the
mining application. The history of such instruments is too extensive to
be entered upon in a footnote, but there are some fundamental
considerations which, if they had been present in the minds of
historical students of this subject, would have considerably abridged
the literature on it. First, there can be no doubt that measuring cords
or rods and boundary stones existed almost from the first division of
land. There is, therefore, no need to try to discover their origins.
Second, the history of surveying and surveying instruments really begins
with the invention of instruments for taking levels, or for the
determination of angles with a view to geometrical calculation. The
meagre facts bearing upon this subject do not warrant the endless
expansion they have received by argument as to what was probable, in
order to accomplish assumed methods of construction among the Ancients.
For instance, the argument that in carrying the Grand Canal over
watersheds with necessary reservoir supply, the Chinese must have had
accurate levelling and surveying instruments before the Christian Era,
and must have conceived in advance a completed work, does not hold water
when any investigation will demonstrate that the canal grew by slow
accretion from the lateral river systems, until it joined almost by
accident. Much the same may be said about the preconception of
engineering results in several other ancient works. There can be no
certainty as to who first invented instruments of the order mentioned
above; for instance, the invention of the dioptra has been ascribed to
Hero, _vide_ his work on the _Dioptra_. He has been assumed to have
lived in the 1st or 2nd Century B.C. Recent investigations, however,
have shown that he lived about 100 A.D. (Sir Thomas Heath, Encyc. Brit.
11th Ed., XIII, 378). As this instrument is mentioned by Vitruvius (50
-0 B.C.) the myth that Hero was the inventor must also disappear.
Incidentally Vitruvius (VIII, 5) describes a levelling instrument called
a _chorobates_, which was a frame levelled either by a groove of water
or by plumb strings. Be the inventor of the _dioptra_ who he may, Hero's
work on that subject contains the first suggestion of mine surveys in
the problems (XIII, XIV, XV, XVI), where geometrical methods are
elucidated for determining the depths required for the connection of
shafts and tunnels. On the compass we give further notes on p. 56. It
was probably an evolution of the 13th Century. As to the application of
angle- and level-determining instruments to underground surveys, so far
as we know there is no reference prior to Agricola, except that of Hero.
Mr. Bennett Brough (Cantor Lecture, London, 1892) points out that the
_Nuetzliche Bergbuechlin_ (see Appendix) describes a mine compass, but
there is not the slightest reference to its use for anything but surface
direction of veins.
Although map-making of a primitive sort requires no instruments, except
legs, the oldest map in the world possesses unusual interest because it
happens to be a map of a mining region. This well-known Turin papyrus
dates from Seti I. (about 1300 B.C.), and it represents certain gold
mines between the Nile and the Red Sea. The best discussion is by Chabas
(_Inscriptions des Mines d'Or_, Chalons-sur-Saone, Paris, 1862, p.
30-36). Fragments of another papyrus, in the Turin Museum, are
considered by Lieblein (_Deux Papyras Hieratiques_, Christiania, 1868)
also to represent a mine of the time of Rameses I. If so, this one dates
from about 1400 B.C. As to an actual map of underground workings
(disregarding illustrations) we know of none until after Agricola's
time. At his time maps were not made, as will be gathered from the text.
[17] For greater clarity we have in a few places interpolated the terms
"major" and "minor" triangles.
[18] The names of the instruments here described in the original text,
their German equivalents in the Glossary, and the terms adopted in
translation are given below:--
LATIN TEXT. GLOSSARY. TERMS ADOPTED.
_Funiculus_ -- Cord
_Pertica_ _Stab_ Rod
_Hemicyclium_ _Donlege bretlein_ Hemicycle
_Tripus_ _Stul_ Tripod
_Instrumentum cui _Compass_ Compass
index_
_Orbis_ _Scheube_ Orbis
_Libra stativa_ _Auffsafz_ Standing plummet
level
_Libra pensilis_ _Wage_ Suspended plummet
level
_Instrumentum cui _Der schiner Swiss compass
index Alpinum_ compass_
[19] It is interesting to note that the ratio of any length so obtained,
to the whole length of the staff, is practically equal to the cosine of
the angle represented by the corresponding gradation on the hemicycle;
the gradations on the rod forming a fairly accurate table of cosines.
[20] It must be understood that instead of "plotting" a survey on a
reduced scale on paper, as modern surveyors do, the whole survey was
reproduced in full scale on the "surveyor's field."
BOOK VI.
Digging of veins I have written of, and the timbering of shafts,
tunnels, drifts, and other excavations, and the art of surveying. I will
now speak first of all, of the iron tools with which veins and rocks are
broken, then of the buckets into which the lumps of earth, rock, metal,
and other excavated materials are thrown, in order that they may be
drawn, conveyed, or carried out. Also, I will speak of the water vessels
and drains, then of the machines of different kinds,[1] and lastly of
the maladies of miners. And while all these matters are being described
accurately, many methods of work will be explained.
[Illustration 150 (Iron tools): A--First "iron tool." B--Second.
C--Third. D--Fourth.[2] E--Wedge. F--Iron block. G--Iron plate.
H--Wooden handle. I--Handle inserted in first tool.]
There are certain iron tools which the miners designate by names of
their own, and besides these, there are wedges, iron blocks, iron
plates, hammers, crowbars, pikes, picks, hoes, and shovels. Of those
which are especially referred to as "iron tools" there are four
varieties, which are different from one another in length or thickness,
but not in shape, for the upper end of all of them is broad and square,
so that it can be struck by the hammer. The lower end is pointed so as
to split the hard rocks and veins with its point. All of these have eyes
except the fourth. The first, which is in daily use among miners, is
three-quarters of a foot long, a digit and a half wide, and a digit
thick. The second is of the same width as the first, and the same
thickness, but one and one half feet long, and is used to shatter the
hardest veins in such a way that they crack open. The third is the same
length as the second, but is a little wider and thicker; with this one
they dig the bottoms of those shafts which slowly accumulate water. The
fourth is nearly three palms and one digit long, two digits thick, and
in the upper end it is three digits wide, in the middle it is one palm
wide, and at the lower end it is pointed like the others; with this they
cut out the harder veins. The eye in the first tool is one palm distant
from the upper end, in the second and third it is seven digits distant;
each swells out around the eye on both sides, and into it they fit a
wooden handle, which they hold with one hand, while they strike the iron
tool with a hammer, after placing it against the rock. These tools are
made larger or smaller as necessary. The smiths, as far as possible,
sharpen again all that become dull.
A wedge is usually three palms and two digits long and six digits wide;
at the upper end, for a distance of a palm, it is three digits thick,
and beyond that point it becomes thinner by degrees, until finally it is
quite sharp.
The iron block is six digits in length and width; at the upper end it
is two digits thick, and at the bottom a digit and a half. The iron
plate is the same length and width as the iron block, but it is very
thin. All of these, as I explained in the last book, are used when the
hardest kind of veins are hewn out. Wedges, blocks, and plates, are
likewise made larger or smaller.
[Illustration 151 (Hammers): A--Smallest of the smaller hammers.
B--Intermediate. C--Largest. D--Small kind of the larger hammer.
E--Large kind. F--Wooden handle. G--Handle fixed in the smallest
hammer.]
Hammers are of two kinds, the smaller ones the miners hold in one hand,
and the larger ones they hold with both hands. The former, because of
their size and use, are of three sorts. With the smallest, that is to
say, the lightest, they strike the second "iron tool;" with the
intermediate one the first "iron tool;" and with the largest the third
"iron tool"; this one is two digits wide and thick. Of the larger sort
of hammers there are two kinds; with the smaller they strike the fourth
"iron tool;" with the larger they drive the wedges into the cracks; the
former are three, and the latter five digits wide and thick, and a foot
long. All swell out in their middle, in which there is an eye for a
handle, but in most cases the handles are somewhat light, in order that
the workmen may be able to strike more powerful blows by the hammer's
full weight being thus concentrated.
[Illustration 152a (Crowbars): A--Round crowbar. B--Flat crowbar.
C--Pike.]
The iron crowbars are likewise of two kinds, and each kind is pointed
at one end. One is rounded, and with this they pierce to a shaft full of
water when a tunnel reaches to it; the other is flat, and with this they
knock out of the stopes on to the floor, the rocks which have been
softened by the fire, and which cannot be dislodged by the pike. A
miner's pike, like a sailor's, is a long rod having an iron head.
[Illustration 152b (Picks): A--Pick. B--Hoe. C--Shovel.]
The miner's pick differs from a peasant's pick in that the latter is
wide at the bottom and sharp, but the former is pointed. It is used to
dig out ore which is not hard, such as earth. Likewise a hoe and shovel
are in no way different from the common articles, with the one they
scrape up earth and sand, with the other they throw it into vessels.
Now earth, rock, mineral substances and other things dug out with the
pick or hewn out with the "iron tools" are hauled out of the shaft in
buckets, or baskets, or hide buckets; they are drawn out of tunnels in
wheelbarrows or open trucks, and from both they are sometimes carried in
trays.
[Illustration 154a (Buckets for hoisting ore)]
[Illustration 154b (Buckets for hoisting ore): A--Small bucket. B--Large
bucket. C--Staves. D--Iron hoops. E--Iron straps. F--Iron straps on the
bottom. G--Hafts. H--Iron bale. I--Hook of drawing-rope. K--Basket.
L--Hide bucket or sack.]
Buckets are of two kinds, which differ in size, but not in material or
shape. The smaller for the most part hold only about one _metreta_; the
larger are generally capable of carrying one-sixth of a _congius_;
neither is of unchangeable capacity, but they often vary.[3] Each is
made of staves circled with hoops, one of which binds the top and the
other the bottom. The hoops are sometimes made of hazel and oak, but
these are easily broken by dashing against the shaft, while those made
of iron are more durable. In the larger buckets the staves are thicker
and wider, as also are both hoops, and in order that the buckets may be
more firm and strong, they have eight iron straps, somewhat broad, four
of which run from the upper hoop downwards, and four from the lower hoop
upwards, as if to meet each other. The bottom of each bucket, both
inside and outside, is furnished with two or three straps of iron, which
run from one side of the lower hoop to the other, but the straps which
are on the outside are fixed crosswise. Each bucket has two iron hafts
which project above the edge, and it has an iron semi-circular bale
whose lower ends are fixed directly into the hafts, that the bucket may
be handled more easily. Each kind of bucket is much deeper than it is
wide, and each is wider at the top, in order that the material which is
dug out may be the more easily poured in and poured out again. Into the
smaller buckets strong boys, and into larger ones men, fill earth from
the bottom of the shaft with hoes; or the other material dug up is
shovelled into them or filled in with their hands, for which reason
these men are called "shovellers.[4]" Afterward they fix the hook of the
drawing-rope into the bale; then the buckets are drawn up by
machines--the smaller ones, because of their lighter weight, by machines
turned by men, and the larger ones, being heavier, by the machines
turned by horses. Some, in place of these buckets, substitute baskets
which hold just as much, or even more, since they are lighter than the
buckets; some use sacks made of ox-hide instead of buckets, and the
drawing-rope hook is fastened to their iron bale, usually three of these
filled with excavated material are drawn up at the same time as three
are being lowered and three are being filled by boys. The latter are
generally used at Schneeberg and the former at Freiberg.
[Illustration 155 (Wheelbarrows): A--Small wheelbarrow. B--Long planks
thereof. C--End-boards. D--Small wheel. E--Larger barrow. F--Front
end-board thereof.]
That which we call a _cisium_[5] is a vehicle with one wheel, not with
two, such as horses draw. When filled with excavated material it is
pushed by a workman out of tunnels or sheds. It is made as follows: two
planks are chosen about five feet long, one foot wide, and two digits
thick; of each of these the lower side is cut away at the front for a
length of one foot, and at the back for a length of two feet, while the
middle is left whole. Then in the front parts are bored circular holes,
in order that the ends of an axle may revolve in them. The intermediate
parts of the planks are perforated twice near the bottom, so as to
receive the heads of two little cleats on which the planks are fixed;
and they are also perforated in the middle, so as to receive the heads
of two end-boards, while keys fixed in these projecting heads strengthen
the whole structure. The handles are made out of the extreme ends of the
long planks, and they turn downward at the ends that they may be grasped
more firmly in the hands. The small wheel, of which there is only one,
neither has a nave nor does it revolve around the axle, but turns around
with it. From the felloe, which the Greeks called [Greek: apsides], two
transverse spokes fixed into it pass through the middle of the axle
toward the opposite felloe; the axle is square, with the exception of
the ends, each of which is rounded so as to turn in the opening. A
workman draws out this barrow full of earth and rock and draws it back
empty. Miners also have another wheelbarrow, larger than this one, which
they use when they wash earth mixed with tin-stone on to which a stream
has been turned. The front end-board of this one is deeper, in order
that the earth which has been thrown into it may not fall out.
[Illustration 156 (Trucks): A--Rectangular iron bands on truck. B--Its
iron straps. C--Iron axle. D--Wooden rollers. E--Small iron keys.
F--Large blunt iron pin. G--Same truck upside down.]
The open truck has a capacity half as large again as a wheelbarrow; it
is about four feet long and about two and a half feet wide and deep; and
since its shape is rectangular, it is bound together with three
rectangular iron bands, and besides these there are iron straps on all
sides. Two small iron axles are fixed to the bottom, around the ends of
which wooden rollers revolve on either side; in order that the rollers
shall not fall off the immovable axles, there are small iron keys. A
large blunt pin fixed to the bottom of the truck runs in a groove of a
plank in such a way that the truck does not leave the beaten track.
Holding the back part with his hands, the carrier pushes out the truck
laden with excavated material, and pushes it back again empty. Some
people call it a "dog"[6], because when it moves it makes a noise which
seems to them not unlike the bark of a dog. This truck is used when they
draw loads out of the longest tunnels, both because it is moved more
easily and because a heavier load can be placed in it.
[Illustration 157 (Batea): A--Small batea. B--Rope. C--Large batea.]
Bateas[7] are hollowed out of a single block of wood; the smaller kind
are generally two feet long and one foot wide. When they have been
filled with ore, especially when but little is dug from the shafts and
tunnels, men either carry them out on their shoulders, or bear them away
hung from their necks. Pliny[8] is our authority that among the
ancients everything which was mined was carried out on men's shoulders,
but in truth this method of carrying forth burdens is onerous, since it
causes great fatigue to a great number of men, and involves a large
expenditure for labour; for this reason it has been rejected and
abandoned in our day. The length of the larger batea is as much as three
feet, the width up to a foot and a palm. In these bateas the metallic
earth is washed for the purpose of testing it.
[Illustration 158a (Buckets for hoisting water): A--Smaller
water-bucket. B--Larger water-bucket. C--Dipper.]
Water-vessels differ both in the use to which they are put and in the
material of which they are made; some draw the water from the shafts and
pour it into other things, as dippers; while some of the vessels filled
with water are drawn out by machines, as buckets and bags; some are made
of wood, as the dippers and buckets, and others of hides, as the bags.
The water-buckets, just like the buckets which are filled with dry
material, are of two kinds, the smaller and the larger, but these are
unlike the other buckets at the top, as in this case they are narrower,
in order that the water may not be spilled by being bumped against the
timbers when they are being drawn out of the shafts, especially those
considerably inclined. The water is poured into these buckets by
dippers, which are small wooden buckets, but unlike the water-buckets,
they are neither narrow at the top nor bound with iron hoops, but with
hazel,--because there is no necessity for either. The smaller buckets
are drawn up by machines turned by men, the larger ones by those turned
by horses.
[Illustration 158b (Bags for hoisting water): A--Water-bag which takes
in water by itself. B--Water-bag into which water pours when it is
pushed with a shovel.]
Our people give the name of water-bags to those very large skins for
carrying water which are made of two, or two and a half, ox-hides. When
these water-bags have undergone much wear and use, first the hair comes
off them and they become bald and shining; after this they become torn.
If the tear is but a small one, a piece of smooth notched stick is put
into the broken part, and the broken bag is bound into its notches on
either side and sewn together; but if it is a large one, they mend it
with a piece of ox-hide. The water-bags are fixed to the hook of a
drawing-chain and let down and dipped into the water, and as soon as
they are filled they are drawn up by the largest machine. They are of
two kinds; the one kind take in the water by themselves; the water pours
into the other kind when it is pushed in a certain way by a wooden
shovel.
[Illustration 159 (Trough): A--Trough. B--Hopper.]
When the water has been drawn out from the shafts, it is run off in
troughs, or into a hopper, through which it runs into the trough.
Likewise the water which flows along the sides of the tunnels is carried
off in drains. These are composed of two hollowed beams joined firmly
together, so as to hold the water which flows through them, and they are
covered by planks all along their course, from the mouth of the tunnel
right up to the extreme end of it, to prevent earth or rock falling into
them and obstructing the flow of the water. If much mud gradually
settles in them the planks are raised and the drains are cleaned out,
for they would otherwise become stopped up and obstructed by this
accident. With regard to the trough lying above ground, which miners
place under the hoppers which are close by the shaft houses, these are
usually hollowed out of single trees. Hoppers are generally made of four
planks, so cut on the lower side and joined together that the top part
of the hopper is broader and the bottom part narrower.
I have sufficiently indicated the nature of the miners' iron tools and
their vessels. I will now explain their machines, which are of three
kinds, that is, hauling machines, ventilating machines, and ladders. By
means of the hauling machines loads are drawn out of the shafts; the
ventilating machines receive the air through their mouths and blow it
into shafts or tunnels, for if this is not done, diggers cannot carry on
their labour without great difficulty in breathing; by the steps of the
ladders the miners go down into the shafts and come up again.
[Illustration 161 (Windlass): A--Timber placed in front of the shaft.
B--Timber placed at the back of the shaft. C--Pointed stakes.
D--Cross-timbers. E--Posts or thick planks. F--Iron sockets. G--Barrel.
H--Ends of barrel. I--Pieces of wood. K--handle. L--Drawing-rope. M--Its
hook. N--Bucket. O--Bale of the bucket.]
Hauling machines are of varied and diverse forms, some of them being
made with great skill, and if I am not mistaken, they were unknown to
the Ancients. They have been invented in order that water may be drawn
from the depths of the earth to which no tunnels reach, and also the
excavated material from shafts which are likewise not connected with a
tunnel, or if so, only with very long ones. Since shafts are not all of
the same depth, there is a great variety among these hauling machines.
Of those by which dry loads are drawn out of the shafts, five sorts are
in the most common use, of which I will now describe the first. Two
timbers a little longer than the shaft are placed beside it, the one in
the front of the shaft, the other at the back. Their extreme ends have
holes through which stakes, pointed at the bottom like wedges, are
driven deeply into the ground, so that the timbers may remain
stationary. Into these timbers are mortised the ends of two
cross-timbers, one laid on the right end of the shaft, while the other
is far enough from the left end that between it and that end there
remains suitable space for placing the ladders. In the middle of the
cross-timbers, posts are fixed and secured with iron keys. In hollows at
the top of these posts thick iron sockets hold the ends of the barrel,
of which each end projects beyond the hollow of the post, and is
mortised into the end of another piece of wood a foot and a half long, a
palm wide and three digits thick; the other end of these pieces of wood
is seven digits wide, and into each of them is fixed a round handle,
likewise a foot and a half long. A winding-rope is wound around the
barrel and fastened to it at the middle part. The loop at each end of
the rope has an iron hook which is engaged in the bale of a bucket, and
so when the windlass revolves by being turned by the cranks, a loaded
bucket is always being drawn out of the shaft and an empty one is being
sent down into it. Two robust men turn the windlass, each having a
wheelbarrow near him, into which he unloads the bucket which is drawn up
nearest to him; two buckets generally fill a wheelbarrow; therefore when
four buckets have been drawn up, each man runs his own wheelbarrow out
of the shed and empties it. Thus it happens that if shafts are dug deep,
a hillock rises around the shed of the windlass. If a vein is not
metal-bearing, they pour out the earth and rock without discriminating;
whereas if it is metal-bearing, they preserve these materials, which
they unload separately and crush and wash. When they draw up buckets of
water they empty the water through the hopper into a trough, through
which it flows away.
[Illustration 162 (Windlass): A--Barrel. B--Straight levers. C--Usual
crank. D--Spokes of wheel. E--Rim of the same wheel.]
The next kind of machine, which miners employ when the shaft is deeper,
differs from the first in that it possesses a wheel as well as cranks.
This windlass, if the load is not being drawn up from a great depth, is
turned by one windlass man, the wheel taking the place of the other man.
But if the depth is greater, then the windlass is turned by three men,
the wheel being substituted for a fourth, because the barrel having been
once set in motion, the rapid revolutions of the wheel help, and it can
be turned more easily. Sometimes masses of lead are hung on to this
wheel, or are fastened to the spokes, in order that when it is turned
they depress the spokes by their weight and increase the motion; some
persons for the same reason fasten into the barrel two, three, or four
iron rods, and weight their ends with lumps of lead. The windlass wheel
differs from the wheel of a carriage and from the one which is turned
by water power, for it lacks the buckets of a water-wheel and it lacks
the nave of a carriage wheel. In the place of the nave it has a thick
barrel, in which are mortised the lower ends of the spokes, just as
their upper ends are mortised into the rim. When three windlass men turn
this machine, four straight levers are fixed to the one end of the
barrel, and to the other the crank which is usual in mines, and which is
composed of two limbs, of which the rounded horizontal one is grasped by
the hands; the rectangular limb, which is at right angles to the
horizontal one, has mortised in its lower end the round handle, and in
the upper end the end of the barrel. This crank is worked by one man,
the levers by two men, of whom one pulls while the other pushes; all
windlass workers, whatsoever kind of a machine they may turn, are
necessarily robust that they can sustain such great toil.
[Illustration 163 (Tread whim): A--Upright axle. B--Block. C--Roof beam.
D--Wheel. E--Toothed-drum. F--Horizontal axle. G--Drum composed of
rundles. H--Drawing rope. I--Pole. K--Upright posts. L--Cleats on the
wheel.]
The third kind of machine is less fatiguing for the workman, while it
raises larger loads; even though it is slower, like all other machines
which have drums, yet it reaches greater depths, even to a depth of 180
feet. It consists of an upright axle with iron journals at its
extremities, which turn in two iron sockets, the lower of which is fixed
in a block set in the ground and the upper one in the roof beam. This
axle has at its lower end a wheel made of thick planks joined firmly
together, and at its upper end a toothed drum; this toothed drum turns
another drum made of rundles, which is on a horizontal axle. A
winding-rope is wound around this latter axle, which turns in iron
bearings set in the beams. So that they may not fall, the two workmen
grasp with their hands a pole fixed to two upright posts, and then
pushing the cleats of the lower wheel backward with their feet, they
revolve the machine; as often as they have drawn up and emptied one
bucket full of excavated material, they turn the machine in the opposite
direction and draw out another.
[Illustration 165 (Horse whim): A--Upright beams. B--Sills laid flat
upon the ground. C--Posts. D--Area. E--Sill set at the bottom of the
hole. F--Axle. G--Double cross-beams. H--Drum. I--Winding-ropes.
K--Bucket. L--Small pieces of wood hanging from double cross-beams.
M--Short wooden block. N--Chain. O--Pole bar. P--Grappling hook. (Some
members mentioned in the text are not shown).]
The fourth machine raises burdens once and a half as large again as the
two machines first explained. When it is made, sixteen beams are erected
each forty feet long, one foot thick and one foot wide, joined at the
top with clamps and widely separated at the bottom. The lower ends of
all of them are mortised into separate sills laid flat upon the ground;
these sills are five feet long, a foot and a half wide, and a foot
thick. Each beam is also connected with its sill by a post, whose upper
end is mortised into the beam and its lower end mortised into the sill;
these posts are four feet long, one foot thick, and one foot wide. Thus
a circular area is made, the diameter of which is fifty feet; in the
middle of this area a hole is sunk to a depth of ten feet, and rammed
down tight, and in order to give it sufficient firmness, it is
strengthened with contiguous small timbers, through which pins are
driven, for by them the earth around the hole is held so that it cannot
fall in. In the bottom of the hole is planted a sill, three or four feet
long and a foot and a half thick and wide; in order that it may remain
fixed, it is set into the small timbers; in the middle of it is a steel
socket in which the pivot of the axle turns. In like manner a timber is
mortised into two of the large beams, at the top beneath the clamps;
this has an iron bearing in which the other iron journal of the axle
revolves. Every axle used in mining, to speak of them once for all, has
two iron journals, rounded off on all sides, one fixed with keys in the
centre of each end. That part of this journal which is fixed to the end
of the axle is as broad as the end itself and a digit thick; that which
projects beyond the axle is round and a palm thick, or thicker if
necessity requires; the ends of each miner's axle are encircled and
bound by an iron band to hold the journal more securely. The axle of
this machine, except at the ends, is square, and is forty feet long, a
foot and a half thick and wide. Mortised and clamped into the axle above
the lower end are the ends of four inclined beams; their outer ends
support two double cross-beams similarly mortised into them; the
inclined beams are eighteen feet long, three palms thick, and five wide.
The two cross-beams are fixed to the axle and held together by wooden
keys so that they will not separate, and they are twenty-four feet long.
Next, there is a drum which is made of three wheels, of which the middle
one is seven feet distant from the upper one and from the lower one; the
wheels have four spokes which are supported by the same number of
inclined braces, the lower ends of which are joined together round the
axle by a clamp; one end of each spoke is mortised into the axle and the
other into the rim. There are rundles all round the wheels, reaching
from the rim of the lowest one to the rim of the middle one, and
likewise from the rim of the middle wheel to the rim of the top one;
around these rundles are wound the drawing-ropes, one between the lowest
wheel and the middle one, the other between the middle and top wheels.
The whole of this construction is shaped like a cone, and is covered
with a shingle roof, with the exception of that square part which faces
the shaft. Then cross-beams, mortised at both ends, connect a double row
of upright posts; all of these are eighteen feet long, but the posts are
one foot thick and one foot wide, and the cross-beams are three palms
thick and wide. There are sixteen posts and eight cross-beams, and upon
these cross-beams are laid two timbers a foot wide and three palms
thick, hollowed out to a width of half a foot and to a depth of five
digits; the one is laid upon the upper cross-beams and the other upon
the lower; each is long enough to reach nearly from the drum of the whim
to the shaft. Near the same drum each timber has a small round wooden
roller six digits thick, whose ends are covered with iron bands and
revolve in iron rings. Each timber also has a wooden pulley, which
together with its iron axle revolves in holes in the timber. These
pulleys are hollowed out all round, in order that the drawing-rope may
not slip out of them, and thus each rope is drawn tight and turns over
its own roller and its own pulley. The iron hook of each rope is engaged
with the bale of the bucket. Further, with regard to the double
cross-beams which are mortised to the lower part of the main axle, to
each end of them there is mortised a small piece of wood four feet long.
These appear to hang from the double cross-beams, and a short wooden
block is fixed to the lower part of them, on which a driver sits. Each
of these blocks has an iron clavis which holds a chain, and that in turn
a pole-bar. In this way it is possible for two horses to draw this whim,
now this way and now that; turn by turn one bucket is drawn out of the
shaft full and another is let down into it empty; if, indeed, the shaft
is very deep four horses turn the whim. When a bucket has been drawn up,
whether filled with dry or wet materials, it must be emptied, and a
workman inserts a grappling hook and overturns it; this hook hangs on a
chain made of three or four links, fixed to a timber.
[Illustration 167 (Horse whim): A--Toothed drum which is on the upright
axle. B--Horizontal axle. C--Drum which is made of rundles. D--Wheel
near it. E--Drum made of hubs. F--Brake. G--Oscillating beam. H--Short
beam. I--Hook.]
The fifth machine is partly like the whim, and partly like the third rag
and chain pump, which draws water by balls when turned by horse power,
as I will explain a little later. Like this pump, it is turned by horse
power and has two axles, namely, an upright one--about whose lower end,
which descends into an underground chamber, there is a toothed drum--and
a horizontal one, around which there is a drum made of rundles. It has
indeed two drums around its horizontal axle, similar to those of the big
machine, but smaller, because it draws buckets from a shaft almost two
hundred and forty feet deep. One drum is made of hubs to which cleats
are fixed, and the other is made of rundles; and near the latter is a
wheel two feet deep, measured on all sides around the axle, and one foot
wide; and against this impinges a brake,[10] which holds the whim when
occasion demands that it be stopped. This is necessary when the hide
buckets are emptied after being drawn up full of rock fragments or
earth, or as often as water is poured out of buckets similarly drawn up;
for this machine not only raises dry loads, but also wet ones, just like
the other four machines which I have already described. By this also,
timbers fastened on to its winding-chain are let down into a shaft. The
brake is made of a piece of wood one foot thick and half a foot long,
projecting from a timber that is suspended by a chain from one end of a
beam which oscillates on an iron pin, this in turn being supported in
the claws of an upright post; and from the other end of this oscillating
beam a long timber is suspended by a chain, and from this long timber
again a short beam is suspended. A workman sits on the short beam when
the machine needs to be stopped, and lowers it; he then inserts a plank
or small stick so that the two timbers are held down and cannot be
raised. In this way the brake is raised, and seizing the drum, presses
it so tightly that sparks often fly from it; the suspended timber to
which the short beam is attached, has several holes in which the chain
is fixed, so that it may be raised as much as is convenient. Above
this wheel there are boards to prevent the water from dripping down and
wetting it, for if it becomes wet the brake will not grip the machine so
well. Near the other drum is a pin from which hangs a chain, in the last
link of which there is an iron hook three feet long; a ring is fixed to
the bottom of the bucket, and this hook, being inserted into it, holds
the bucket back so that the water may be poured out or the fragments of
rock emptied.
[Illustration 168 (Sleigh for Ore): A--Sledge with box placed on it.
B--Sledge with sacks placed on it. C--Stick. D--Dogs with pack-saddles.
E--Pigskin sacks tied to a rope.]
The miners either carry, draw, or roll down the mountains the ore which
is hauled out of the shafts by these five machines or taken out of the
tunnels. In the winter time our people place a box on a sledge and draw
it down the low mountains with a horse; and in this season they also
fill sacks made of hide and load them on dogs, or place two or three of
them on a small sledge which is higher in the fore part and lower at the
back. Sitting on these sacks, not without risk of his life, the bold
driver guides the sledge as it rushes down the mountain into the valleys
with a stick, which he carries in his hand; when it is rushing down too
quickly he arrests it with the stick, or with the same stick brings it
back to the track when it is turning aside from its proper course. Some
of the Noricians[11] collect ore during the winter into sacks made of
bristly pigskins, and drag them down from the highest mountains, which
neither horses, mules nor asses can climb. Strong dogs, that are trained
to bear pack saddles, carry these sacks when empty into the mountains.
When they are filled with ore, bound with thongs, and fastened to a
rope, a man, winding the rope round his arm or breast, drags them down
through the snow to a place where horses, mules, or asses bearing
pack-saddles can climb. There the ore is removed from the pigskin sacks
and put into other sacks made of double or triple twilled linen thread,
and these placed on the pack-saddles of the beasts are borne down to the
works where the ores are washed or smelted. If, indeed, the horses,
mules, or asses are able to climb the mountains, linen sacks filled with
ore are placed on their saddles, and they carry these down the narrow
mountain paths, which are passable neither by wagons nor sledges, into
the valleys lying below the steeper portions of the mountains. But on
the declivity of cliffs which beasts cannot climb, are placed long open
boxes made of planks, with transverse cleats to hold them together; into
these boxes is thrown the ore which has been brought in wheelbarrows,
and when it has run down to the level it is gathered into sacks, and the
beasts either carry it away on their backs or drag it away after it has
been thrown into sledges or wagons. When the drivers bring ore down
steep mountain slopes they use two-wheeled carts, and they drag behind
them on the ground the trunks of two trees, for these by their weight
hold back the heavily-laden carts, which contain ore in their boxes, and
check their descent, and but for these the driver would often be obliged
to bind chains to the wheels. When these men bring down ore from
mountains which do not have such declivities, they use wagons whose beds
are twice as long as those of the carts. The planks of these are so put
together that, when the ore is unloaded by the drivers, they can be
raised and taken apart, for they are only held together by bars. The
drivers employed by the owners of the ore bring down thirty or sixty
wagon-loads, and the master of the works marks on a stick the number of
loads for each driver. But some ore, especially tin, after being taken
from the mines, is divided into eight parts, or into nine, if the owners
of the mine give "ninth parts" to the owners of the tunnel. This is
occasionally done by measuring with a bucket, but more frequently planks
are put together on a spot where, with the addition of the level ground
as a base, it forms a hollow box. Each owner provides for removing,
washing, and smelting that portion which has fallen to him.
(Illustration p. 170).
[Illustration 170 (Wagons for Hauling Ore): A--Horses with pack-saddles.
B--Long box placed on the slope of the cliff. C--Cleats thereof.
D--Wheelbarrow. E--Two-wheeled cart. F--Trunks of trees. G--Wagon.
H--Ore being unloaded from the wagon. I--Bars. K--Master of the works
marking the number of carts on a stick. L--Boxes into which are thrown
the ore which has to be divided.]
Into the buckets, drawn by these five machines, the boys or men throw
the earth and broken rock with shovels, or they fill them with their
hands; hence they get their name of shovellers. As I have said, the same
machines raise not only dry loads, but also wet ones, or water; but
before I explain the varied and diverse kinds of machines by which
miners are wont to draw water alone, I will explain how heavy bodies,
such as axles, iron chains, pipes, and heavy timbers, should be lowered
into deep vertical shafts. A windlass is erected whose barrel has on
each end four straight levers; it is fixed into upright beams and around
it is wound a rope, one end of which is fastened to the barrel and the
other to those heavy bodies which are slowly lowered down by workmen;
and if these halt at any part of the shaft they are drawn up a little
way. When these bodies are very heavy, then behind this windlass another
is erected just like it, that their combined strength may be equal to
the load, and that it may be lowered slowly. Sometimes for the same
reason, a pulley is fastened with cords to the roof-beam, and the rope
descends and ascends over it.
[Illustration 171 (Windlass): A--Windlass. B--Straight levers.
C--Upright beams. D--Rope. E--Pulley. F--Timbers to be lowered.]
Water is either hoisted or pumped out of shafts. It is hoisted up after
being poured into buckets or water-bags; the water-bags are generally
brought up by a machine whose water-wheels have double paddles, while
the buckets are brought up by the five machines already described,
although in certain localities the fourth machine also hauls up
water-bags of moderate size. Water is drawn up also by chains of
dippers, or by suction pumps, or by "rag and chain" pumps.[12] When
there is but a small quantity, it is either brought up in buckets or
drawn up by chains of dippers or suction pumps, and when there is much
water it is either drawn up in hide bags or by rag and chain pumps.
[Illustration 173 (Chain Pumps): A--Iron frame. B--Lowest axle.
C--Fly-wheel. D--Smaller drum made of rundles. E--Second axle.
F--Smaller toothed wheel. G--Larger drum made of rundles. H--Upper axle.
I--Larger toothed wheel. K--Bearings. L--Pillow. M--Framework. N--Oak
timber. O--Support of iron bearing. P--Roller. Q--Upper drum. R--Clamps.
S--Chain. T--Links. V--Dippers. X--Crank. Y--Lower drum or balance
weight.]
First of all, I will describe the machines which draw water by chains of
dippers, of which there are three kinds. For the first, a frame is made
entirely of iron bars; it is two and a half feet high, likewise two and
a half feet long, and in addition one-sixth and one-quarter of a digit
long, one-fourth and one-twenty-fourth of a foot wide. In it there are
three little horizontal iron axles, which revolve in bearings or wide
pillows of steel, and also four iron wheels, of which two are made with
rundles and the same number are toothed. Outside the frame, around the
lowest axle, is a wooden fly-wheel, so that it can be more readily
turned, and inside the frame is a smaller drum which is made of eight
rundles, one-sixth and one twenty-fourth of a foot long. Around the
second axle, which does not project beyond the frame, and is therefore
only two and a half feet and one-twelfth and one-third part of a digit
long, there is on the one side, a smaller toothed wheel, which has
forty-eight teeth, and on the other side a larger drum, which is
surrounded by twelve rundles one-quarter of a foot long. Around the
third axle, which is one inch and one-third thick, is a larger toothed
wheel projecting one foot from the axle in all directions, which has
seventy-two teeth. The teeth of each wheel are fixed in with screws,
whose threads are screwed into threads in the wheel, so that those teeth
which are broken can be replaced by others; both the teeth and rundles
are steel. The upper axle projects beyond the frame, and is so skilfully
mortised into the body of another axle that it has the appearance of
being one; this axle proceeds through a frame made of beams which stands
around the shaft, into an iron fork set in a stout oak timber, and turns
on a roller made of pure steel. Around this axle is a drum of the kind
possessed by those machines which draw water by rag and chain; this drum
has triple curved iron clamps, to which the links of an iron chain hook
themselves, so that a great weight cannot tear them away. These links
are not whole like the links of other chains, but each one being curved
in the upper part on each side catches the one which comes next, whereby
it presents the appearance of a double chain. At the point where one
catches the other, dippers made of iron or brass plates and holding half
a _congius_[13] are bound to them with thongs; thus, if there are one
hundred links there will be the same number of dippers pouring out
water. When the shafts are inclined, the mouths of the dippers project
and are covered on the top that they may not spill out the water, but
when the shafts are vertical the dippers do not require a cover. By
fitting the end of the lowest small axle into the crank, the man who
works the crank turns the axle, and at the same time the drum whose
rundles turn the toothed wheel of the second axle; by this wheel is
driven the one that is made of rundles, which again turns the toothed
wheel of the upper small axle and thus the drum to which the clamps are
fixed. In this way the chain, together with the empty dippers, is slowly
let down, close to the footwall side of the vein, into the sump to the
bottom of the balance drum, which turns on a little iron axle, both ends
of which are set in a thick iron bearing. The chain is rolled round the
drum and the dippers fill with water; the chain being drawn up close to
the hangingwall side, carries the dippers filled with water above the
drum of the upper axle. Thus there are always three of the dippers
inverted and pouring water into a lip, from which it flows away into the
drain of the tunnel. This machine is less useful, because it cannot be
constructed without great expense, and it carries off but little water
and is somewhat slow, as also are other machines which possess a great
number of drums.
[Illustration 174 (Chain Pumps): A--Wheel which is turned by treading.
B--Axle. C--Double chain. D--Link of double chain. E--Dippers. F--Simple
clamps. G--Clamp with triple curves.]
The next machine of this kind, described in a few words by
Vitruvius,[14] more rapidly brings up dippers, holding a _congius_; for
this reason, it is more useful than the first one for drawing water out
of shafts, into which much water is continually flowing. This machine
has no iron frame nor drums, but has around its axle a wooden wheel
which is turned by treading; the axle, since it has no drum, does not
last very long. In other respects this pump resembles the first kind,
except that it differs from it by having a double chain. Clamps should
be fixed to the axle of this machine, just as to the drum of the other
one; some of these are made simple and others with triple curves, but
each kind has four barbs.
[Illustration 175 (Chain Pumps): A--Wheel whose paddles are turned by
the force of the stream. B--Axle. C--Drum of axle, to which clamps are
fixed. D--Chain. E--Link. F--Dippers. G--Balance drum.]
The third machine, which far excels the two just described, is made when
a running stream can be diverted to a mine; the impetus of the stream
striking the paddles revolves a water-wheel in place of the wheel turned
by treading. With regard to the axle, it is like the second machine, but
the drum which is round the axle, the chain, and the balance drum, are
like the first machine. It has much more capacious dippers than even the
second machine, but since the dippers are frequently broken, miners
rarely use these machines; for they prefer to lift out small quantities
of water by the first five machines or to draw it up by suction pumps,
or, if there is much water, to drain it by the rag and chain pump or to
bring it up in water-bags.
[Illustration 177 (Suction Pumps): A--Sump. B--Pipes. C--Flooring.
D--Trunk. E--Perforations of trunk. F--Valve. G--Spout. H--Piston-rod.
I--Hand-bar of piston. K--Shoe. L--Disc with round openings. M--Disc
with oval openings. N--Cover. O--This man is boring logs and making them
into pipes. P--Borer with auger. Q--Wider borer.]
Enough, then, of the first sort of pumps. I will now explain the other,
that is the pump which draws, by means of pistons, water which has been
raised by suction. Of these there are seven varieties, which though they
differ from one another in structure, nevertheless confer the same
benefits upon miners, though some to a greater degree than others. The
first pump is made as follows. Over the sump is placed a flooring,
through which a pipe--or two lengths of pipe, one of which is joined
into the other--are let down to the bottom of the sump; they are
fastened with pointed iron clamps driven in straight on both sides, so
that the pipes may remain fixed. The lower end of the lower pipe is
enclosed in a trunk two feet deep; this trunk, hollow like the pipe,
stands at the bottom of the sump, but the lower opening of it is blocked
with a round piece of wood; the trunk has perforations round about,
through which water flows into it. If there is one length of pipe, then
in the upper part of the trunk which has been hollowed out there is
enclosed a box of iron, copper, or brass, one palm deep, but without a
bottom, and a rounded valve so tightly closes it that the water, which
has been drawn up by suction, cannot run back; but if there are two
lengths of pipe, the box is enclosed in the lower pipe at the point of
junction. An opening or a spout in the upper pipe reaches to the drain
of the tunnel. Thus the workman, eager at his labour, standing on the
flooring boards, pushes the piston down into the pipe and draws it out
again. At the top of the piston-rod is a hand-bar and the bottom is
fixed in a shoe; this is the name given to the leather covering, which
is almost cone-shaped, for it is so stitched that it is tight at the
lower end, where it is fixed to the piston-rod which it surrounds, but
in the upper end where it draws the water it is wide open. Or else an
iron disc one digit thick is used, or one of wood six digits thick, each
of which is far superior to the shoe. The disc is fixed by an iron key
which penetrates through the bottom of the piston-rod, or it is screwed
on to the rod; it is round, with its upper part protected by a cover,
and has five or six openings, either round or oval, which taken together
present a star-like appearance; the disc has the same diameter as the
inside of the pipe, so that it can be just drawn up and down in it. When
the workman draws the piston up, the water which has passed in at the
openings of the disc, whose cover is then closed, is raised to the hole
or little spout, through which it flows away; then the valve of the box
opens, and the water which has passed into the trunk is drawn up by the
suction and rises into the pipe; but when the workman pushes down the
piston, the valve closes and allows the disc again to draw in the water.
[Illustration 178 (Suction Pumps): A--Erect timber. B--Axle. C--Sweep
which turns about the axle. D--Piston rod. E--Cross-bar. F--Ring with
which two pipes are generally joined.]
The piston of the second pump is more easily moved up and down. When
this pump is made, two beams are placed over the sump, one near the
right side of it, and the other near the left. To one beam a pipe is
fixed with iron clamps; to the other is fixed either the forked branch
of a tree or a timber cut out at the top in the shape of a fork, and
through the prongs of the fork a round hole is bored. Through a wide
round hole in the middle of a sweep passes an iron axle, so fastened
in the holes in the fork that it remains fixed, and the sweep turns on
this axle. In one end of the sweep the upper end of a piston-rod is
fastened with an iron key; at the other end a cross-bar is also fixed,
to the extreme ends of which are handles to enable it to be held more
firmly in the hands. And so when the workman pulls the cross-bar upward,
he forces the piston into the pipe; when he pushes it down again he
draws the piston out of the pipe; and thus the piston carries up the
water which has been drawn in at the openings of the disc, and the water
flows away through the spout into the drains. This pump, like the next
one, is identical with the first in all that relates to the piston,
disc, trunk, box, and valve.
[Illustration 179 (Suction Pumps): A--Posts. B--Axle. C--Wooden bars.
D--Piston rod. E--Short piece of wood. F--Drain. G--This man is
diverting the water which is flowing out of the drain, to prevent it
from flowing into the trenches which are being dug.]
The third pump is not unlike the one just described, but in place of one
upright, posts are erected with holes at the top, and in these holes the
ends of an axle revolve. To the middle of this axle are fixed two wooden
bars, to the end of one of which is fixed the piston, and to the end of
the other a heavy piece of wood, but short, so that it can pass between
the two posts and may move backward and forward. When the workman pushes
this piece of wood, the piston is drawn out of the pipe; when it returns
by its own weight, the piston is pushed in. In this way, the water
which the pipe contains is drawn through the openings in the disc and
emptied by the piston through the spout into the drain. There are some
who place a hand-bar underneath in place of the short piece of wood.
This pump, as also the last before described, is less generally used
among miners than the others.
[Illustration 180 (Duplex suction Pumps): A--Box. B--Lower part of box.
C--Upper part of same. D--Clamps. E--Pipes below the box. F--Column pipe
fixed above the box. G--Iron axle. H--Piston-rods. I--Washers to protect
the bearings. K--Leathers. L--Eyes in the axle. M--Rods whose ends are
weighted with lumps of lead. N--Crank. (_This plate is unlettered in the
first edition but corrected in those later._)]
The fourth kind is not a simple pump but a duplex one. It is made as
follows. A rectangular block of beechwood, five feet long, two and a
half feet wide, and one and a half feet thick, is cut in two and
hollowed out wide and deep enough so that an iron axle with cranks can
revolve in it. The axle is placed between the two halves of this box,
and the first part of the axle, which is in contact with the wood, is
round and the straight end forms a journal. Then the axle is bent down
the depth of a foot and again bent so as to continue straight, and at
this point a round piston-rod hangs from it; next it is bent up as far
as it was bent down; then it continues a little way straight again, and
then it is bent up a foot and again continues straight, at which point a
second round piston-rod is hung from it; afterward it is bent down the
same distance as it was bent up the last time; the other end of it,
which also acts as a journal, is straight. This part which protrudes
through the wood is protected by two iron washers in the shape of discs,
to which are fastened two leather washers of the same shape and size, in
order to prevent the water which is drawn into the box from gushing out.
These discs are around the axle; one of them is inside the box and the
other outside. Beyond this, the end of the axle is square and has two
eyes, in which are fixed two iron rods, and to their ends are weighted
lumps of lead, so that the axle may have a greater propensity to
revolve; this axle can easily be turned when its end has been mortised
in a crank. The upper part of the box is the shallower one, and the
lower part the deeper; the upper part is bored out once straight down
through the middle, the diameter of the opening being the same as the
outside diameter of the column pipe; the lower box has, side by side,
two apertures also bored straight down; these are for two pipes, the
space of whose openings therefore is twice as great as that of the upper
part; this lower part of the box is placed upon the two pipes, which are
fitted into it at their upper ends, and the lower ends of these pipes
penetrate into trunks which stand in the sump. These trunks have
perforations through which the water flows into them. The iron axle is
placed in the inside of the box, then the two iron piston-rods which
hang from it are let down through the two pipes to the depth of a foot.
Each piston has a screw at its lower end which holds a thick iron plate,
shaped like a disc and full of openings, covered with a leather, and
similarly to the other pump it has a round valve in a little box. Then
the upper part of the box is placed upon the lower one and properly
fitted to it on every side, and where they join they are bound by wide
thick iron plates, and held with small wide iron wedges, which are
driven in and are fastened with clamps. The first length of column pipe
is fixed into the upper part of the box, and another length of pipe
extends it, and a third again extends this one, and so on, another
extending on another, until the uppermost one reaches the drain of the
tunnel. When the crank worker turns the axle, the pistons in turn draw
the water through their discs; since this is done quickly, and since the
area of openings of the two pipes over which the box is set, is twice as
large as the opening of the column pipe which rises from the box, and
since the pistons do not lift the water far up, the impetus of the water
from the lower pipes forces it to rise and flow out of the column pipe
into the drain of the tunnel. Since a wooden box frequently cracks open,
it is better to make it of lead or copper or brass.
[Illustration 182 (Suction Pumps): A--Tappets of piston-rods. B--Cams of
the barrel. C--Square upper parts of piston-rods. D--Lower rounded parts
of piston-rods. E--Cross-beams. F--Pipes. G--Apertures of pipes.
H--Trough. (Fifth kind of pump--see p. 181).]
The fifth kind of pump is still less simple, for it is composed of two
or three pumps whose pistons are raised by a machine turned by men, for
each piston-rod has a tappet which is raised, each in succession, by two
cams on a barrel; two or four strong men turn it. When the pistons
descend into the pipes their discs draw the water; when they are raised
these force the water out through the pipes. The upper part of each of
these piston-rods, which is half a foot square, is held in a slot in a
cross-beam; the lower part, which drops down into the pipes, is made of
another piece of wood and is round. Each of these three pumps is
composed of two lengths of pipe fixed to the shaft timbers. This
machine draws the water higher, as much as twenty-four feet. If the
diameter of the pipes is large, only two pumps are made; if smaller,
three, so that by either method the volume of water is the same. This
also must be understood regarding the other machines and their pipes.
Since these pumps are composed of two lengths of pipe, the little iron
box having the iron valve which I described before, is not enclosed in a
trunk, but is in the lower length of pipe, at that point where it joins
the upper one; thus the rounded part of the piston-rod is only as long
as the upper length of pipe; but I will presently explain this more
clearly.
[Illustration 183 (Suction Pumps): A--Water-wheel. B--Axle. C--Trunk on
which the lowest pipe stands. D--Basket surrounding trunk. (Sixth kind
of pump--see p. 184.)]
The sixth kind of pump would be just the same as the fifth were it not
that it has an axle instead of a barrel, turned not by men but by a
water-wheel, which is revolved by the force of water striking its
buckets. Since water-power far exceeds human strength, this machine
draws water through its pipes by discs out of a shaft more than one
hundred feet deep. The bottom of the lowest pipe, set in the sump, not
only of this pump but also of the others, is generally enclosed in a
basket made of wicker-work, to prevent wood shavings and other things
being sucked in. (See p. 183.)
[Illustration 185 (Suction Pumps): A--shaft. B--Bottom pump. C--First
tank. D--Second pump. E--Second tank. F--Third pump. G--Trough. H--The
iron set in the axle. I--First pump rod. K--Second pump rod. L--Third
pump rod. M--First piston rod. N--Second piston rod. O--Third piston
rod. P--Little axles. Q--"Claws."]
The seventh kind of pump, invented ten years ago, which is the most
ingenious, durable, and useful of all, can be made without much expense.
It is composed of several pumps, which do not, like those last
described, go down into the shaft together, but of which one is below
the other, for if there are three, as is generally the case, the lower
one lifts the water of the sump and pours it out into the first tank;
the second pump lifts again from that tank into a second tank, and the
third pump lifts it into the drain of the tunnel. A wheel fifteen feet
high raises the piston-rods of all these pumps at the same time and
causes them to drop together. The wheel is made to revolve by paddles,
turned by the force of a stream which has been diverted to the mountain.
The spokes of the water-wheel are mortised in an axle six feet long and
one foot thick, each end of which is surrounded by an iron band, but in
one end there is fixed an iron journal; to the other end is attached an
iron like this journal in its posterior part, which is a digit thick and
as wide as the end of the axle itself. Then the iron extends
horizontally, being rounded and about three digits in diameter, for the
length of a foot, and serves as a journal; thence, it bends to a height
of a foot in a curve, like the horn of the moon, after which it again
extends straight out for one foot; thus it comes about that this last
straight portion, as it revolves in an orbit becomes alternately a foot
higher and a foot lower than the first straight part. From this round
iron crank there hangs the first flat pump-rod, for the crank is fixed
in a perforation in the upper end of this flat pump-rod just as the iron
key of the first set of "claws" is fixed into the lower end. In order to
prevent the pump-rod from slipping off it, as it could easily do, and
that it may be taken off when necessary, its opening is wider than the
corresponding part of the crank, and it is fastened on both sides by
iron keys. To prevent friction, the ends of the pump-rods are protected
by iron plates or intervening leathers. This first pump-rod is about
twelve feet long, the other two are twenty-six feet, and each is a palm
wide and three digits thick. The sides of each pump-rod are covered and
protected by iron plates, which are held on by iron screws, so that a
part which has received damage can be repaired. In the "claws" is set a
small round axle, a foot and a half long and two palms thick. The ends
are encircled by iron bands to prevent the iron journals which revolve
in the iron bearings of the wood from slipping out of it.[15] From this
little axle the wooden "claws" extend two feet, with a width and
thickness of six digits; they are three palms distant from each other,
and both the inner and outer sides are covered with iron plates. Two
rounded iron keys two digits thick are immovably fixed into the claws.
The one of these keys perforates the lower end of the first pump-rod,
and the upper end of the second pump-rod which is held fast. The other
key, which is likewise immovable, perforates the iron end of the first
piston-rod, which is bent in a curve and is immovable. Each such
piston-rod is thirteen feet long and three digits thick, and descends
into the first pipe of each pump to such depth that its disc nearly
reaches the valve-box. When it descends into the pipe, the water,
penetrating through the openings of the disc, raises the leather, and
when the piston-rod is raised the water presses down the leather, and
this supports its weight; then the valve closes the box as a door closes
an entrance. The pipes are joined by two iron bands, one palm wide, one
outside the other, but the inner one is sharp all round that it may fit
into each pipe and hold them together. Although at the present time
pipes lack the inner band, still they have nipples by which they are
joined together, for the lower end of the upper one holds the upper end
of the lower one, each being hewn away for a length of seven digits, the
former inside, the latter outside, so that the one can fit into the
other. When the piston-rod descends into the first pipe, that valve
which I have described is closed; when the piston-rod is raised, the
valve is opened so that the water can run in through the perforations.
Each one of such pumps is composed of two lengths of pipe, each of which
is twelve feet long, and the inside diameter is seven digits. The lower
one is placed in the sump of the shaft, or in a tank, and its lower end
is blocked by a round piece of wood, above which there are six
perforations around the pipe through which the water flows into it. The
upper part of the upper pipe has a notch one foot deep and a palm wide,
through which the water flows away into a tank or trough. Each tank is
two feet long and one foot wide and deep. There is the same number of
axles, "claws," and rods of each kind as there are pumps; if there are
three pumps, there are only two tanks, because the sump of the shaft and
the drain of the tunnel take the place of two. The following is the way
this machine draws water from a shaft. The wheel being turned raises the
first pump-rod, and the pump-rod raises the first "claw," and thus also
the second pump-rod, and the first piston-rod; then the second pump-rod
raises the second "claw," and thus the third pump-rod and the second
piston-rod; then the third pump-rod raises the third "claw" and the
third piston-rod, for there hangs no pump-rod from the iron key of
these claws, for it can be of no use in the last pump. In turn, when the
first pump-rod descends, each set of "claws" is lowered, each pump-rod
and each piston-rod. And by this system, at the same time the water is
lifted into the tanks and drained out of them; from the sump at the
bottom of the shaft it is drained out, and it is poured into the trough
of the tunnel. Further, around the main axle there may be placed two
water wheels, if the river supplies enough water to turn them, and from
the back part of each round iron crank, one or two pump-rods can be
hung, each of which can move the piston-rods of three pumps. Lastly, it
is necessary that the shafts from which the water is pumped out in pipes
should be vertical, for as in the case of the hauling machines, all
pumps which have pipes do not draw the water so high if the pipes are
inclined in inclined shafts, as if they are placed vertically in
vertical shafts.
[Illustration 187 (Suction Pumps): A--Water wheel of upper machine.
B--Its pump. C--Its trough. D--Wheel of lower machine. E--Its pump.
F--Race.]
If the river does not supply enough water-power to turn the
last-described pump, which happens because of the nature of the locality
or occurs during the summer season when there are daily droughts, a
machine is built with a wheel so low and light that the water of ever so
little a stream can turn it. This water, falling into a race, runs
therefrom on to a second high and heavy wheel of a lower machine, whose
pump lifts the water out of a deep shaft. Since, however, the water of
so small a stream cannot alone revolve the lower water-wheel, the axle
of the latter is turned at the start with a crank worked by two men, but
as soon as it has poured out into a pool the water which has been drawn
up by the pumps, the upper wheel draws up this water by its own pump,
and pours it into the race, from which it flows on to the lower
water-wheel and strikes its buckets. So both this water from the mine,
as well as the water of the stream, being turned down the races on to
that subterranean wheel of the lower machine, turns it, and water is
pumped out of the deeper part of the shaft by means of two or three
pumps.[16]
[Illustration 189 (Duplex suction Pumps): A--Upper axle. B--Wheel whose
buckets the force of the stream strikes. C--Toothed drum. D--Second
axle. E--Drum composed of rundles. F--Curved round irons. G--Rows of
pumps.]
If the stream supplies enough water straightway to turn a higher and
heavier water-wheel, then a toothed drum is fixed to the other end of
the axle, and this turns the drum made of rundles on another axle set
below it. To each end of this lower axle there is fitted a crank of
round iron curved like the horns of the moon, of the kind employed in
machines of this description. This machine, since it has rows of pumps
on each side, draws great quantities of water.
[Illustration 191 (Rag and Chain Pumps): A--Wheel. B--Axle. C--Journals.
D--Pillows. E--Drum. F--Clamps. G--Drawing-chain. H--Timbers. I--Balls.
K--Pipe. L--Race of stream.]
Of the rag and chain pumps there are six kinds known to us, of which the
first is made as follows: A cave is dug under the surface of earth or in
a tunnel, and timbered on all sides by stout posts and planks, to
prevent either the men from being crushed or the machine from being
broken by its collapse. In this cave, thus timbered, is placed a
water-wheel fitted to an angular axle. The iron journals of the axle
revolve in iron pillows, which are held in timbers of sufficient
strength. The wheel is generally twenty-four feet high, occasionally
thirty, and in no way different from those which are made for grinding
corn, except that it is a little narrower. The axle has on one side a
drum with a groove in the middle of its circumference, to which are
fixed many four-curved iron clamps. In these clamps catch the links of
the chain, which is drawn through the pipes out of the sump, and which
again falls, through a timbered opening, right down to the bottom into
the sump to a balancing drum. There is an iron band around the small
axle of the balancing drum, each journal of which revolves in an iron
bearing fixed to a timber. The chain turning about this drum brings up
the water by the balls through the pipes. Each length of pipe is
encircled and protected by five iron bands, a palm wide and a digit
thick, placed at equal distances from each other; the first band on the
pipe is shared in common with the preceding length of pipe into which it
is fitted, the last band with the succeeding length of pipe which is
fitted into it. Each length of pipe, except the first, is bevelled on
the outer circumference of the upper end to a distance of seven digits
and for a depth of three digits, in order that it may be inserted into
the length of pipe which goes before it; each, except the last, is
reamed out on the inside of the lower end to a like distance, but to the
depth of a palm, that it may be able to take the end of the pipe which
follows. And each length of pipe is fixed with iron clamps to the
timbers of the shaft, that it may remain stationary. Through this
continuous series of pipes, the water is drawn by the balls of the chain
up out of the sump as far as the tunnel, where it flows but into the
drains through an aperture in the highest pipe. The balls which lift the
water are connected by the iron links of the chain, and are six feet
distant from one another; they are made of the hair of a horse's tail
sewn into a covering to prevent it from being pulled out by the iron
clamps on the drum; the balls are of such size that one can be held in
each hand. If this machine is set up on the surface of the earth, the
stream which turns the water-wheel is led away through open-air ditches;
if in a tunnel, the water is led away through the subterranean drains.
The buckets of the water-wheel, when struck by the impact of the stream,
move forward and turn the wheel, together with the drum, whereby the
chain is wound up and the balls expel the water through the pipes. If
the wheel of this machine is twenty-four feet in diameter, it draws
water from a shaft two hundred and ten feet deep; if thirty feet in
diameter, it will draw water from a shaft two hundred and forty feet
deep. But such work requires a stream with greater water-power.
The next pump has two drums, two rows of pipes and two drawing-chains
whose balls lift out the water; otherwise they are like the last pump.
This pump is usually built when an excessive amount of water flows into
the sump. These two pumps are turned by water-power; indeed, water draws
water.
The following is the way of indicating the increase or decrease of the
water in an underground sump, whether it is pumped by this rag and chain
pump or by the first pump, or the third, or some other. From a beam
which is as high above the shaft as the sump is deep, is hung a cord, to
one end of which there is fastened a stone, the other end being attached
to a plank. The plank is lowered down by an iron wire fastened to the
other end; when the stone is at the mouth of the shaft the plank is
right down the shaft in the sump, in which water it floats. This plank
is so heavy that it can drag down the wire and its iron clasp and hook,
together with the cord, and thus pull the stone upwards. Thus, as the
water decreases, the plank descends and the stone is raised; on the
contrary, when the water increases the plank rises and the stone is
lowered. When the stone nearly touches the beam, since this indicates
that the water has been exhausted from the sump by the pump, the
overseer in charge of the machine closes the water-race and stops the
water-wheel; when the stone nearly touches the ground at the side of the
shaft, this indicates that the sump is full of water which has again
collected in it, because the water raises the plank and thus the stone
drags back both the rope and the iron wire; then the overseer opens the
water-race, whereupon the water of the stream again strikes the buckets
of the water-wheel and turns the pump. As workmen generally cease from
their labours on the yearly holidays, and sometimes on working days,
and are thus not always near the pump, and as the pump, if necessary,
must continue to draw water all the time, a bell rings aloud
continuously, indicating that this pump, or any other kind, is uninjured
and nothing is preventing its turning. The bell is hung by a cord from a
small wooden axle held in the timbers which stand over the shaft, and a
second long cord whose upper end is fastened to the small axle is
lowered into the shaft; to the lower end of this cord is fastened a
piece of wood; and as often as a cam on the main axle strikes it, so
often does the bell ring and give forth a sound.
[Illustration 193 (Rag and Chain Pumps): A--Upright axle. B--Toothed
wheel. C--Teeth. D--Horizontal axle. E--Drum which is made of rundles.
F--Second drum. G--Drawing-chain. H--The balls.]
The third pump of this kind is employed by miners when no river capable
of turning a water-wheel can be diverted, and it is made as follows.
They first dig a chamber and erect strong timbers and planks to prevent
the sides from falling in, which would overwhelm the pump and kill the
men. The roof of the chamber is protected with contiguous timbers, so
arranged that the horses which pull the machine can travel over it. Next
they again set up sixteen beams forty feet long and one foot wide and
thick, joined by clamps at the top and spreading apart at the bottom,
and they fit the lower end of each beam into a separate sill laid flat
on the ground, and join these by a post; thus there is created a
circular area of which the diameter is fifty feet. Through an opening in
the centre of this area there descends an upright square axle,
forty-five feet long and a foot and a half wide and thick; its lower
pivot revolves in a socket in a block laid flat on the ground in the
chamber, and the upper pivot revolves in a bearing in a beam which is
mortised into two beams at the summit beneath the clamps; the lower
pivot is seventeen feet distant from either side of the chamber, _i.e._,
from its front and rear. At the height of a foot above its lower end,
the axle has a toothed wheel, the diameter of which is twenty-two feet.
This wheel is composed of four spokes and eight rim pieces; the spokes
are fifteen feet long and three-quarters of a foot wide and thick[17];
one end of them is mortised in the axle, the other in the two rims where
they are joined together. These rims are three-quarters of a foot thick
and one foot wide, and from them there rise and project upright teeth
three-quarters of a foot high, half a foot wide, and six digits thick.
These teeth turn a second horizontal axle by means of a drum composed of
twelve rundles, each three feet long and six digits wide and thick. This
drum, being turned, causes the axle to revolve, and around this axle
there is a drum having iron clamps with fourfold curves in which catch
the links of a chain, which draws water through pipes by means of balls.
The iron journals of this horizontal axle revolve on pillows which are
set in the centre of timbers. Above the roof of the chamber there are
mortised into the upright axle the ends of two beams which rise
obliquely; the upper ends of these beams support double cross-beams,
likewise mortised to the axle. In the outer end of each cross-beam there
is mortised a small wooden piece which appears to hang down; in this
wooden piece there is similarly mortised at the lower end a short
board; this has an iron key which engages a chain, and this chain again
a pole-bar. This machine, which draws water from a shaft two hundred and
forty feet deep, is worked by thirty-two horses; eight of them work for
four hours, and then these rest for twelve hours, and the same number
take their place. This kind of machine is employed at the foot of the
Harz[18] mountains and in the neighbourhood. Further, if necessity
arises, several pumps of this kind are often built for the purpose of
mining one vein, but arranged differently in different localities
varying according to the depth. At Schemnitz, in the Carpathian
mountains, there are three pumps, of which the lowest lifts water from
the lowest sump to the first drains, through which it flows into the
second sump; the intermediate one lifts from the second sump to the
second drain, from which it flows into the third sump; and the upper one
lifts it to the drains of the tunnel, through which it flows away. This
system of three machines of this kind is turned by ninety-six horses;
these horses go down to the machines by an inclined shaft, which slopes
and twists like a screw and gradually descends. The lowest of these
machines is set in a deep place, which is distant from the surface of
the ground 660 feet.
[Illustration 194 (Rag and Chain Pumps): A--Axle. B--Drum.
C--Drawing-chain. D--Balls. E--Clamps.]
The fourth species of pump belongs to the same genera, and is made as
follows. Two timbers are erected, and in openings in them, the ends of a
barrel revolve. Two or four strong men turn the barrel, that is to say,
one or two pull the cranks, and one or two push them, and in this way
help the others; alternately another two or four men take their place.
The barrel of this machine, just like the horizontal axle of the other
machines, has a drum whose iron clamps catch the links of a
drawing-chain. Thus water is drawn through the pipes by the balls from a
depth of forty-eight feet. Human strength cannot draw water higher than
this, because such very heavy labour exhausts not only men, but even
horses; only water-power can drive continuously a drum of this kind.
Several pumps of this kind, as of the last, are often built for the
purpose of mining on a single vein, but they are arranged differently
for different positions and depths.
[Illustration 195 (Rag and Chain Pumps): A--Axles. B--Levers. C--Toothed
drum. D--Drum made of rundles. E--Drum in which iron clamps are fixed.]
The fifth pump of this kind is partly like the third and partly like
the fourth, because it is turned by strong men like the last, and like
the third it has two axles and three drums, though each axle is
horizontal. The journals of each axle are so fitted in the pillows of
the beams that they cannot fly out; the lower axle has a crank at one
end and a toothed drum at the other end; the upper axle has at one end a
drum made of rundles, and at the other end, a drum to which are fixed
iron clamps, in which the links of a chain catch in the same way as
before, and from the same depth, draw water through pipes by means of
balls. This revolving machine is turned by two pairs of men alternately,
for one pair stands working while the other sits taking a rest; while
they are engaged upon the task of turning, one pulls the crank and the
other pushes, and the drums help to make the pump turn more easily.
[Illustration 197 (Rag and Chain Pumps): A--Axles. B--Wheel which is
turned by treading. C--Toothed wheel. D--Drum made of rundles. E--Drum
to which are fixed iron clamps. F--Second wheel. G--Balls.]
The sixth pump of this kind likewise has two axles. At one end of the
lower axle is a wheel which is turned by two men treading, this is
twenty-three feet high and four feet wide, so that one man may stand
alongside the other. At the other end of this axle is a toothed wheel.
The upper[19] axle has two drums and one wheel; the first drum is made
of rundles, and to the other there are fixed the iron clamps. The wheel
is like the one on the second machine which is chiefly used for drawing
earth and broken rock out of shafts. The treaders, to prevent themselves
from falling, grasp in their hands poles which are fixed to the inner
sides of the wheel. When they turn this wheel, the toothed drum being
made to revolve, sets in motion the other drum which is made of rundles,
by which means again the links of the chain catch to the cleats of the
third drum and draw water through pipes by means of balls,--from a depth
of sixty-six feet.
[Illustration 199 (Baling Water): A--Reservoir. B--Race. C, D--Levers.
E, F--Troughs under the water gates. G, H--Double rows of buckets.
I--Axle. K--Larger drum. L--Drawing-chain. M--Bag. N--Hanging cage.
O--Man who directs the machine. P, Q--Men emptying bags.]
But the largest machine of all those which draw water is the one which
follows. First of all a reservoir is made in a timbered chamber; this
reservoir is eighteen feet long and twelve feet wide and high. Into this
reservoir a stream is diverted through a water-race or through the
tunnel; it has two entrances and the same number of gates. Levers are
fixed to the upper part of these gates, by which they can be raised and
let down again, so that by one way the gates are opened and in the other
way closed. Beneath the openings are two plank troughs which carry the
water flowing from the reservoir, and pour it on to the buckets of the
water-wheel, the impact of which turns the wheel. The shorter trough
carries the water, which strikes the buckets that turn the wheel toward
the reservoir, and the longer trough carries the water which strikes
those buckets that turn the wheel in the opposite direction. The casing
or covering of the wheel is made of joined boards to which strips are
affixed on the inner side. The wheel itself is thirty-six feet in
diameter, and is mortised to an axle, and it has, as I have already
said, two rows of buckets, of which one is set the opposite way to the
other, so that the wheel may be turned toward the reservoir or in the
opposite direction. The axle is square and is thirty-five feet long
and two feet thick and wide. Beyond the wheel, at a distance of six
feet, the axle has four hubs, one foot wide and thick, each one of which
is four feet distant from the next; to these hubs are fixed by iron
nails as many pieces of wood as are necessary to cover the hubs, and, in
order that the wood pieces may fit tight, they are broader on the
outside and narrower on the inside; in this way a drum is made, around
which is wound a chain to whose ends are hooked leather bags. The reason
why a drum of this kind is made, is that the axle may be kept in good
condition, because this drum when it becomes worn away by use can be
repaired easily. Further along the axle, not far from the end, is
another drum one foot broad, projecting two feet on all sides around the
axle. And to this, when occasion demands, a brake is applied forcibly
and holds back the machine; this kind of brake I have explained before.
Near the axle, in place of a hopper, there is a floor with a
considerable slope, having in front of the shaft a width of fifteen feet
and the same at the back; at each side of it there is a stout post
carrying an iron chain which has a large hook. Five men operate this
machine; one lets down the doors which close the reservoir gates, or by
drawing down the levers, opens the water-races; this man, who is the
director of this machine, stands in a hanging cage beside the reservoir.
When one bag has been drawn out nearly as far as the sloping floor, he
closes the water gate in order that the wheel may be stopped; when the
bag has been emptied he opens the other water gate, in order that the
other set of buckets may receive the water and drive the wheel in the
opposite direction. If he cannot close the water-gate quickly enough,
and the water continues to flow, he calls out to his comrade and bids
him raise the brake upon the drum and stop the wheel. Two men
alternately empty the bags, one standing on that part of the floor which
is in front of the shaft, and the other on that part which is at the
back. When the bag has been nearly drawn up--of which fact a certain
link of the chain gives warning--the man who stands on the one part of
the floor, catches a large iron hook in one link of the chain, and pulls
out all the subsequent part of the chain toward the floor, where the bag
is emptied by the other man. The object of this hook is to prevent the
chain, by its own weight, from pulling down the other empty bag, and
thus pulling the whole chain from its axle and dropping it down the
shaft. His comrade in the work, seeing that the bag filled with water
has been nearly drawn out, calls to the director of the machine and bids
him close the water of the tower so that there will be time to empty the
bag; this being emptied, the director of the machine first of all
slightly opens the other water-gate of the tower to allow the end of the
chain, together with the empty bag, to be started into the shaft again,
and then opens entirely the water-gates. When that part of the chain
which has been pulled on to the floor has been wound up again, and has
been let down over the shaft from the drum, he takes out the large hook
which was fastened into a link of the chain. The fifth man stands in a
sort of cross-cut beside the sump, that he may not be hurt, if it should
happen that a link is broken and part of the chain or anything else
should fall down; he guides the bag with a wooden shovel, and fills it
with water if it fails to take in the water spontaneously. In these
days, they sew an iron band into the top of each bag that it may
constantly remain open, and when lowered into the sump may fill itself
with water, and there is no need for a man to act as governor of the
bags. Further, in these days, of those men who stand on the floor the
one empties the bags, and the other closes the gates of the reservoir
and opens them again, and the same man usually fixes the large hook in
the link of the chain. In this way, three men only are employed in
working this machine; or even--since sometimes the one who empties the
bag presses the brake which is raised against the other drum and thus
stops the wheel--two men take upon themselves the whole labour.
But enough of haulage machines; I will now speak of ventilating
machines. If a shaft is very deep and no tunnel reaches to it, or no
drift from another shaft connects with it, or when a tunnel is of great
length and no shaft reaches to it, then the air does not replenish
itself. In such a case it weighs heavily on the miners, causing them to
breathe with difficulty, and sometimes they are even suffocated, and
burning lamps are also extinguished. There is, therefore, a necessity
for machines which the Greeks call [Greek: pneumatikai] and the Latins
_spiritales_--though they do not give forth any sound--which enable the
miners to breathe easily and carry on their work.
[Illustration 201 (Windsails for Ventilation): A--Sills. B--Pointed
stakes. C--Cross-beams. D--Upright planks. E--Hollows. F--Winds.
G--Covering disc. H--Shafts. I--Machine without a covering.]
These devices are of three genera. The first receives and diverts into
the shaft the blowing of the wind, and this genus is divided into three
species, of which the first is as follows. Over the shaft--to which no
tunnel connects--are placed three sills a little longer than the shaft,
the first over the front, the second over the middle, and the third over
the back of the shaft. Their ends have openings, through which pegs,
sharpened at the bottom, are driven deeply into the ground so as to hold
them immovable, in the same way that the sills of the windlass are
fixed. Each of these sills is mortised into each of three cross-beams,
of which one is at the right side of the shaft, the second at the left,
and the third in the middle. To the second sill and the second
cross-beam--each of which is placed over the middle of the shaft--planks
are fixed which are joined in such a manner that the one which precedes
always fits into the groove of the one which follows. In this way four
angles and the same number of intervening hollows are created, which
collect the winds that blow from all directions. The planks are roofed
above with a cover made in a circular shape, and are open below, in
order that the wind may not be diverted upward and escape, but may be
carried downward; and thereby the winds of necessity blow into the
shafts through these four openings. However, there is no need to roof
this kind of machine in those localities in which it can be so placed
that the wind can blow down through its topmost part.
[Illustration 202 (Windsails for Ventilation): A--Projecting mouth of
conduit. B--Planks fixed to the mouth of the conduit which does not
project.]
The second machine of this genus turns the blowing wind into a shaft
through a long box-shaped conduit, which is made of as many lengths of
planks, joined together, as the depth of the shaft requires; the joints
are smeared with fat, glutinous clay moistened with water. The mouth of
this conduit either projects out of the shaft to a height of three or
four feet, or it does not project; if it projects, it is shaped like a
rectangular funnel, broader and wider at the top than the conduit
itself, that it may the more easily gather the wind; if it does not
project, it is not broader than the conduit, but planks are fixed to it
away from the direction in which the wind is blowing, which catch the
wind and force it into the conduit.
[Illustration 203 (Windsails for Ventilation): A--Wooden barrels.
B--Hoops. C--Blow-holes. D--Pipe. E--Table. F--Axle. G--Opening in the
bottom of the barrel. H--Wing.]
The third of this genus of machine is made of a pipe or pipes and a
barrel. Above the uppermost pipe there is erected a wooden barrel, four
feet high and three feet in diameter, bound with wooden hoops; it has a
square blow-hole always open, which catches the breezes and guides them
down either by a pipe into a conduit or by many pipes into the shaft. To
the top of the upper pipe is attached a circular table as thick as the
bottom of the barrel, but of a little less diameter, so that the barrel
may be turned around on it; the pipe projects out of the table and is
fixed in a round opening in the centre of the bottom of the barrel. To
the end of the pipe a perpendicular axle is fixed which runs through the
centre of the barrel into a hole in the cover, in which it is fastened,
in the same way as at the bottom. Around this fixed axle and the table
on the pipe, the movable barrel is easily turned by a zephyr, or much
more by a wind, which govern the wing on it. This wing is made of thin
boards and fixed to the upper part of the barrel on the side furthest
away from the blow-hole; this, as I have said, is square and always
open. The wind, from whatever quarter of the world it blows, drives the
wing straight toward the opposite direction, in which way the barrel
turns the blow-hole towards the wind itself; the blow-hole receives the
wind, and it is guided down into the shaft by means of the conduit or
pipes.
[Illustration 204 (Ventilation Fans): A--Drum. B--Box-shaped casing.
C--Blow-hole. D--Second hole. E--Conduit. F--Axle. G--Lever of axle.
H--Rods.]
The second genus of blowing machine is made with fans, and is likewise
varied and of many forms, for the fans are either fitted to a windlass
barrel or to an axle. If to an axle, they are either contained in a
hollow drum, which is made of two wheels and a number of boards joining
them together, or else in a box-shaped casing. The drum is stationary
and closed on the sides, except for round holes of such size that the
axle may turn in them; it has two square blow-holes, of which the upper
one receives the air, while the lower one empties into the conduit
through which the air is led down the shaft. The ends of the axle, which
project on each side of the drum, are supported by forked posts or
hollowed beams plated with thick iron; one end of the axle has a crank,
while in the other end are fixed four rods with thick heavy ends, so
that they weight the axle, and when turned, make it prone to motion as
it revolves. And so, when the workman turns the axle by the crank, the
fans, the description of which I will give a little later, draw in the
air by the blow-hole, and force it through the other blow-hole which
leads to the conduit, and through this conduit the air penetrates into
the shaft.
[Illustration 205 (Ventilation Fans): A--Box-shaped casing placed on the
ground. B--Its blow-hole. C--Its axle with fans. D--Crank of the axle.
E--Rods of same. F--Casing set on timbers. G--Sails which the axle has
outside the casing.]
The one with the box-shaped casing is furnished with just the same
things as the drum, but the drum is far superior to the box; for the
fans so fill the drum that they almost touch it on every side, and drive
into the conduit all the air that has been accumulated; but they cannot
thus fill the box-shaped casing, on account of its angles, into which
the air partly retreats; therefore it cannot be as useful as the drum.
The kind with a box-shaped casing is not only placed on the ground, but
is also set up on timbers like a windmill, and its axle, in place of a
crank, has four sails outside, like the sails of a windmill. When these
are struck by the wind they turn the axle, and in this way its
fans--which are placed within the casing--drive the air through the
blow-hole and the conduit into the shaft. Although this machine has no
need of men whom it is necessary to pay to work the crank, still when
the sky is devoid of wind, as it often is, the machine does not turn,
and it is therefore less suitable than the others for ventilating a
shaft.
[Illustration 206 (Ventilation Fans): A--Hollow drum. B--Its blow-hole.
C--Axle with fans. D--Drum which is made of rundles. E--Lower axle.
F--Its toothed wheel. G--Water wheel.]
In the kind where the fans are fixed to an axle, there is generally a
hollow stationary drum at one end of the axle, and on the other end is
fixed a drum made of rundles. This rundle drum is turned by the toothed
wheel of a lower axle, which is itself turned by a wheel whose buckets
receive the impetus of water. If the locality supplies an abundance of
water this machine is most useful, because to turn the crank does not
need men who require pay, and because it forces air without cessation
through the conduit into the shaft.
[Illustration 207 (Ventilation Fans): A--First kind of fan. B--Second
kind of fan. C--Third kind of fan. D--Quadrangular part of axle.
E--Round part of same. F--Crank.]
Of the fans which are fixed on to an axle contained in a drum or box,
there are three sorts. The first sort is made of thin boards of such
length and width as the height and width of the drum or box require; the
second sort is made of boards of the same width, but shorter, to which
are bound long thin blades of poplar or some other flexible wood; the
third sort has boards like the last, to which are bound double and
triple rows of goose feathers. This last is less used than the second,
which in turn is less used than the first. The boards of the fan are
mortised into the quadrangular parts of the barrel axle.
[Illustration 208 (Bellows for mine ventilation): A--Smaller part of
shaft. B--Square conduit. C--Bellows. D--Larger part of shaft.]
Blowing machines of the third genus, which are no less varied and of no
fewer forms than those of the second genus, are made with bellows, for
by its blasts the shafts and tunnels are not only furnished with air
through conduits or pipes, but they can also be cleared by suction of
their heavy and pestilential vapours. In the latter case, when the
bellows is opened it draws the vapours from the conduits through its
blow-hole and sucks these vapours into itself; in the former case, when
it is compressed, it drives the air through its nozzle into the conduits
or pipes. They are compressed either by a man, or by a horse or by
water-power; if by a man, the lower board of a large bellows is fixed to
the timbers above the conduit which projects out of the shaft, and so
placed that when the blast is blown through the conduit, its nozzle is
set in the conduit. When it is desired to suck out heavy or pestilential
vapours, the blow-hole of the bellows is fitted all round the mouth of
the conduit. Fixed to the upper bellows board is a lever which couples
with another running downward from a little axle, into which it is
mortised so that it may remain immovable; the iron journals of this
little axle revolve in openings of upright posts; and so when the
workman pulls down the lever the upper board of the bellows is raised,
and at the same time the flap of the blow-hole is dragged open by the
force of the wind. If the nozzle of the bellows is enclosed in the
conduit it draws pure air into itself, but if its blow-hole is fitted
all round the mouth of the conduit it exhausts the heavy and
pestilential vapours out of the conduit and thus from the shaft, even if
it is one hundred and twenty feet deep. A stone placed on the upper
board of the bellows depresses it and then the flap of the blow-hole is
closed. The bellows, by the first method, blows fresh air into the
conduit through its nozzle, and by the second method blows out through
the nozzle the heavy and pestilential vapours which have been collected.
In this latter case fresh air enters through the larger part of the
shaft, and the miners getting the benefit of it can sustain their toil.
A certain smaller part of the shaft which forms a kind of estuary,
requires to be partitioned off from the other larger part by
uninterrupted lagging, which reaches from the top of the shaft to the
bottom; through this part the long but narrow conduit reaches down
nearly to the bottom of the shaft.
[Illustration 209 (Bellows for mine ventilation): A--Tunnel. B--Pipe.
C--Nozzle of double bellows.]
When no shaft has been sunk to such depth as to meet a tunnel driven far
into a mountain, these machines should be built in such a manner that
the workman can move them about. Close by the drains of the tunnel
through which the water flows away, wooden pipes should be placed and
joined tightly together in such a manner that they can hold the air;
these should reach from the mouth of the tunnel to its furthest end. At
the mouth of the tunnel the bellows should be so placed that through its
nozzle it can blow its accumulated blasts into the pipes or the conduit;
since one blast always drives forward another, they penetrate into the
tunnel and change the air, whereby the miners are enabled to continue
their work.
[Illustration 211 (Bellows for mine ventilation): A--Machine first
described. B--This workman, treading with his feet, is compressing the
bellows. C--Bellows without nozzles. D--Hole by which heavy vapours or
blasts are blown out. E--Conduits. F--Tunnel. G--Second machine
described. H--Wooden wheel. I--Its steps. K--Bars. L--Hole in same
wheel. M--Pole. N--Third machine described. O--Upright axle. P--Its
toothed drum. Q--Horizontal axle. R--Its drum which is made of rundles.]
If heavy vapours need to be drawn off from the tunnels, generally three
double or triple bellows, without nozzles and closed in the forepart,
are placed upon benches. A workman compresses them by treading with his
feet, just as persons compress those bellows of the organs which give
out varied and sweet sounds in churches. These heavy vapours are thus
drawn along the air-pipes and through the blow-hole of the lower bellows
board, and are expelled through the blow-hole of the upper bellows board
into the open air, or into some shaft or drift. This blow-hole has a
flap-valve, which the noxious blast opens, as often as it passes out.
Since one volume of air constantly rushes in to take the place of
another which has been drawn out by the bellows, not only is the heavy
air drawn out of a tunnel as great as 1,200 feet long, or even longer,
but also the wholesome air is naturally drawn in through that part of
the tunnel which is open outside the conduits. In this way the air is
changed, and the miners are enabled to carry on the work they have
begun. If machines of this kind had not been invented, it would be
necessary for miners to drive two tunnels into a mountain, and
continually, at every two hundred feet at most, to sink a shaft from the
upper tunnel to the lower one, that the air passing into the one, and
descending by the shafts into the other, would be kept fresh for the
miners; this could not be done without great expense.
There are two different machines for operating, by means of horses, the
above described bellows. The first of these machines has on its axle a
wooden wheel, the rim of which is covered all the way round by steps; a
horse is kept continually within bars, like those within which horses
are held to be shod with iron, and by treading these steps with its feet
it turns the wheel, together with the axle; the cams on the axle press
down the sweeps which compress the bellows. The way the instrument is
made which raises the bellows again, and also the benches on which the
bellows rest, I will explain more clearly in Book IX. Each bellows, if
it draws heavy vapours out of a tunnel, blows them out of the hole in
the upper board; if they are drawn out of a shaft, it blows them out
through its nozzle. The wheel has a round hole, which is transfixed with
a pole when the machine needs to be stopped.
The second machine has two axles; the upright one is turned by a horse,
and its toothed drum turns a drum made of rundles on a horizontal axle;
in other respects this machine is like the last. Here, also, the nozzles
of the bellows placed in the conduits blow a blast into the shaft or
tunnel.
[Illustration 212 (Ventilating with Damp Cloth): A--Tunnel. B--Linen
cloth.]
In the same way that this last machine can refresh the heavy air of a
shaft or tunnel, so also could the old system of ventilating by the
constant shaking of linen cloths, which Pliny[20] has explained; the air
not only grows heavier with the depth of a shaft, of which fact he has
made mention, but also with the length of a tunnel.
[Illustration 213 (Descent into Mines): A--Descending into the shaft by
ladders. B--By sitting on a stick. C--By sitting on the dirt.
D--Descending by steps cut in the rock.]
The climbing machines of miners are ladders, fixed to one side of the
shaft, and these reach either to the tunnel or to the bottom of the
shaft. I need not describe how they are made, because they are used
everywhere, and need not so much skill in their construction as care in
fixing them. However, miners go down into mines not only by the steps of
ladders, but they are also lowered into them while sitting on a stick or
a wicker basket, fastened to the rope of one of the three drawing
machines which I described at first. Further, when the shafts are much
inclined, miners and other workmen sit in the dirt which surrounds their
loins and slide down in the same way that boys do in winter-time when
the water on some hillside has congealed with the cold, and to prevent
themselves from falling, one arm is wound about a rope, the upper end of
which is fastened to a beam at the mouth of the shaft, and the lower end
to a stake fixed in the bottom of the shaft. In these three ways miners
descend into the shafts. A fourth way may be mentioned which is employed
when men and horses go down to the underground machines and come up
again, that is by inclined shafts which are twisted like a screw and
have steps cut in the rock, as I have already described.
It remains for me to speak of the ailments and accidents of miners, and
of the methods by which they can guard against these, for we should
always devote more care to maintaining our health, that we may freely
perform our bodily functions, than to making profits. Of the illnesses,
some affect the joints, others attack the lungs, some the eyes, and
finally some are fatal to men.
Where water in shafts is abundant and very cold, it frequently injures
the limbs, for cold is harmful to the sinews. To meet this, miners
should make themselves sufficiently high boots of rawhide, which protect
their legs from the cold water; the man who does not follow this advice
will suffer much ill-health, especially when he reaches old age. On the
other hand, some mines are so dry that they are entirely devoid of
water, and this dryness causes the workmen even greater harm, for the
dust which is stirred and beaten up by digging penetrates into the
windpipe and lungs, and produces difficulty in breathing, and the
disease which the Greeks call [Greek: asthma]. If the dust has corrosive
qualities, it eats away the lungs, and implants consumption in the body;
hence in the mines of the Carpathian Mountains women are found who have
married seven husbands, all of whom this terrible consumption has
carried off to a premature death. At Altenberg in Meissen there is found
in the mines black _pompholyx_, which eats wounds and ulcers to the
bone; this also corrodes iron, for which reason the keys of their sheds
are made of wood. Further, there is a certain kind of _cadmia_[21] which
eats away the feet of the workmen when they have become wet, and
similarly their hands, and injures their lungs and eyes. Therefore, for
their digging they should make for themselves not only boots of
rawhide, but gloves long enough to reach to the elbow, and they should
fasten loose veils over their faces; the dust will then neither be drawn
through these into their windpipes and lungs, nor will it fly into their
eyes. Not dissimilarly, among the Romans[22] the makers of vermilion
took precautions against breathing its fatal dust.
Stagnant air, both that which remains in a shaft and that which remains
in a tunnel, produces a difficulty in breathing; the remedies for this
evil are the ventilating machines which I have explained above. There is
another illness even more destructive, which soon brings death to men
who work in those shafts or levels or tunnels in which the hard rock is
broken by fire. Here the air is infected with poison, since large and
small veins and seams in the rocks exhale some subtle poison from the
minerals, which is driven out by the fire, and this poison itself is
raised with the smoke not unlike _pompholyx_,[23] which clings to the
upper part of the walls in the works in which ore is smelted. If this
poison cannot escape from the ground, but falls down into the pools and
floats on their surface, it often causes danger, for if at any time the
water is disturbed through a stone or anything else, these fumes rise
again from the pools and thus overcome the men, by being drawn in with
their breath; this is even much worse if the fumes of the fire have not
yet all escaped. The bodies of living creatures who are infected with
this poison generally swell immediately and lose all movement and
feeling, and they die without pain; men even in the act of climbing from
the shafts by the steps of ladders fall back into the shafts when the
poison overtakes them, because their hands do not perform their office,
and seem to them to be round and spherical, and likewise their feet. If
by good fortune the injured ones escape these evils, for a little while
they are pale and look like dead men. At such times, no one should
descend into the mine or into the neighbouring mines, or if he is in
them he should come out quickly. Prudent and skilled miners burn the
piles of wood on Friday, towards evening, and they do not descend into
the shafts nor enter the tunnels again before Monday, and in the
meantime the poisonous fumes pass away.
There are also times when a reckoning has to be made with Orcus,[24] for
some metalliferous localities, though such are rare, spontaneously
produce poison and exhale pestilential vapour, as is also the case with
some openings in the ore, though these more often contain the noxious
fumes. In the towns of the plains of Bohemia there are some caverns
which, at certain seasons of the year, emit pungent vapours which put
out lights and kill the miners if they linger too long in them. Pliny,
too, has left a record that when wells are sunk, the sulphurous or
aluminous vapours which arise kill the well-diggers, and it is a test of
this danger if a burning lamp which has been let down is extinguished.
In such cases a second well is dug to the right or left, as an
air-shaft, which draws off these noxious vapours. On the plains they
construct bellows which draw up these noxious vapours and remedy this
evil; these I have described before.
Further, sometimes workmen slipping from the ladders into the shafts
break their arms, legs, or necks, or fall into the sumps and are
drowned; often, indeed, the negligence of the foreman is to blame, for
it is his special work both to fix the ladders so firmly to the timbers
that they cannot break away, and to cover so securely with planks the
sumps at the bottom of the shafts, that the planks cannot be moved nor
the men fall into the water; wherefore the foreman must carefully
execute his own work. Moreover, he must not set the entrance of the
shaft-house toward the north wind, lest in winter the ladders freeze
with cold, for when this happens the men's hands become stiff and
slippery with cold, and cannot perform their office of holding. The men,
too, must be careful that, even if none of these things happen, they do
not fall through their own carelessness.
Mountains, too, slide down and men are crushed in their fall and perish.
In fact, when in olden days Rammelsberg, in Goslar, sank down, so many
men were crushed in the ruins that in one day, the records tell us,
about 400 women were robbed of their husbands. And eleven years ago,
part of the mountain of Altenberg, which had been excavated, became
loose and sank, and suddenly crushed six miners; it also swallowed up a
hut and one mother and her little boy. But this generally occurs in
those mountains which contain _venae cumulatae_. Therefore, miners
should leave numerous arches under the mountains which need support, or
provide underpinning. Falling pieces of rock also injure their limbs,
and to prevent this from happening, miners should protect the shafts,
tunnels, and drifts.
The venomous ant which exists in Sardinia is not found in our mines.
This animal is, as Solinus[25] writes, very small and like a spider in
shape; it is called _solifuga_, because it shuns (_fugit_) the light
(_solem_). It is very common in silver mines; it creeps unobserved and
brings destruction upon those who imprudently sit on it. But, as the
same writer tells us, springs of warm and salubrious waters gush out in
certain places, which neutralise the venom inserted by the ants.
In some of our mines, however, though in very few, there are other
pernicious pests. These are demons of ferocious aspect, about which I
have spoken in my book _De Animantibus Subterraneis_. Demons of this
kind are expelled and put to flight by prayer and fasting.[26]
Some of these evils, as well as certain other things, are the reason why
pits are occasionally abandoned. But the first and principal cause is
that they do not yield metal, or if, for some fathoms, they do bear
metal they become barren in depth. The second cause is the quantity of
water which flows in; sometimes the miners can neither divert this water
into the tunnels, since tunnels cannot be driven so far into the
mountains, or they cannot draw it out with machines because the shafts
are too deep; or if they could draw it out with machines, they do not
use them, the reason undoubtedly being that the expenditure is greater
than the profits of a moderately poor vein. The third cause is the
noxious air, which the owners sometimes cannot overcome either by skill
or expenditure, for which reason the digging is sometimes abandoned, not
only of shafts, but also of tunnels. The fourth cause is the poison
produced in particular places, if it is not in our power either
completely to remove it or to moderate its effects. This is the reason
why the caverns in the Plain known as Laurentius[27] used not to be
worked, though they were not deficient in silver. The fifth cause are
the fierce and murderous demons, for if they cannot be expelled, no one
escapes from them. The sixth cause is that the underpinnings become
loosened and collapse, and a fall of the mountain usually follows; the
underpinnings are then only restored when the vein is very rich in
metal. The seventh cause is military operations. Shafts and tunnels
should not be re-opened unless we are quite certain of the reasons why
the miners have deserted them, because we ought not to believe that our
ancestors were so indolent and spiritless as to desert mines which could
have been carried on with profit. Indeed, in our own days, not a few
miners, persuaded by old women's tales, have re-opened deserted shafts
and lost their time and trouble. Therefore, to prevent future
generations from being led to act in such a way, it is advisable to set
down in writing the reason why the digging of each shaft or tunnel has
been abandoned, just as it is agreed was once done at Freiberg, when the
shafts were deserted on account of the great inrush of water.
END OF BOOK VI.
FOOTNOTES:
[1] This Book is devoted in the main to winding, ventilating, and
pumping machinery. Their mechanical principles are very old. The block
and pulley, the windlass, the use of water-wheels, the transmission of
power through shafts and gear-wheels, chain-pumps, piston-pumps with
valves, were all known to the Greeks and Romans, and possibly earlier.
Machines involving these principles were described by Ctesibius, an
Alexandrian of 250 B.C., by Archimedes (287-212 B.C.), and by Vitruvius
(1st Century B.C.) As to how far these machines were applied to mining
by the Ancients we have but little evidence, and this largely in
connection with handling water. Diodorus Siculus (1st Century B.C.)
referring to the Spanish mines, says (Book V.): "Sometimes at great
depths they meet great rivers underground, but by art give check to the
violence of the streams, for by cutting trenches they divert the
current, and being sure to gain what they aim at when they have begun,
they never leave off till they have finished it. And they admirably pump
out the water with those instruments called Egyptian pumps, invented by
Archimedes, the Syracusan, when he was in Egypt. By these, with constant
pumping by turns they throw up the water to the mouth of the pit and
thus drain the mine; for this engine is so ingeniously contrived that a
vast quantity of water is strangely and with little labour cast out."
Strabo (63 B.C.-24 A.D., III., 2, 9), also referring to Spanish mines,
quoting from Posidonius (about 100 B.C.), says: "He compares with these
(the Athenians) the activity and diligence of the Turdetani, who are in
the habit of cutting tortuous and deep tunnels, and draining the streams
which they frequently encounter by means of Egyptian screws."
(Hamilton's Tran., Vol. I., p. 221). The "Egyptian screw" was
Archimedes' screw, and was thus called because much used by the
Egyptians for irrigation. Pliny (XXXIII., 31) also says, in speaking of
the Spanish silver-lead mines: "The mountain has been excavated for a
distance of 1,500 paces, and along this distance there are
water-carriers standing by torch-light night and day steadily baling the
water (thus) making quite a river." The re-opening of the mines at Rio
Tinto in the middle of the 18th Century disclosed old Roman stopes, in
which were found several water-wheels. These were about 15 feet in
diameter, lifting the water by the reverse arrangement to an overshot
water-wheel. A wooden Archimedian screw was also found in the
neighbourhood. (Nash, The Rio Tinto Mine, its History and Romance,
London, 1904).
Until early in the 18th Century, water formed the limiting factor in the
depth of mines. To the great devotion to this water problem we owe the
invention of the steam engine. In 1705 Newcomen--no doubt inspired by
Savery's unsuccessful attempt--invented his engine, and installed the
first one on a colliery at Wolverhampton, in Staffordshire. With its
success, a new era was opened to the miner, to be yet further extended
by Watt's improvements sixty years later. It should be a matter of
satisfaction to mining engineers that not only was the steam engine the
handiwork of their profession, but that another mining engineer,
Stephenson, in his effort to further the advance of his calling,
invented the locomotive.
[2] While these particular tools serve the same purpose as the "gad" and
the "moil," the latter are not fitted with handles, and we have,
therefore, not felt justified in adopting these terms, but have given a
literal rendering of the Latin.
The Latin and old German terms for these tools were:--
First Iron tool = _Ferramentum primum_ = _Bergeisen_.
Second " = " _secundum_ = _Rutzeisen_.
Third " = " _tertium_ = _Sumpffeisen_.
Fourth " = " _quartum_ = _Fimmel_.
Wedge = _Cuneus_ = _Keil_.
Iron block = _Lamina_ = _Plotz_.
Iron plate = _Bractea_ = _Feder_.
The German words obviously had local value and do not bear translation
literally.
[3] One _metreta_, a Greek measure, equalled about nine English gallons,
and a _congius_ contained about six pints.
[4] _Ingestores_. This is a case of Agricola coining a name for workmen
from the work, the term being derived from _ingero_, to pour or to throw
in, used in the previous clause--hence the "reason." See p. xxxi.
[5] _Cisium_. A two-wheeled cart. In the preface Agricola gives this as
an example of his intended adaptations. See p. xxxi.
[6] _Canis_. The Germans in Agricola's time called a truck a _hundt_--a
hound.
[7] _Alveus_,--"Tray." The Spanish term _batea_ has been so generally
adopted into the mining vocabulary for a wooden bowl for these purposes,
that we introduce it here.
[8] Pliny (XXXIII., 21). "The fragments are carried on workmen's
shoulders; night and day each passes the material to his neighbour, only
the last of them seeing the daylight."
[10] _Harpago_,--A "grapple" or "hook."
[11] Ancient Noricum covered the region of modern Tyrol, with parts of
Bavaria, Salzburg, etc.
[12] _Machina quae pilis aquas haurit_. "Machine which draws water with
balls." This apparatus is identical with the Cornish "rag and chain
pump" of the same period, and we have therefore adopted that term.
[13] A _congius_ contained about six pints.
[14] Vitruvius (X., 9). "But if the water is to be supplied to still
higher places, a double chain of iron is made to revolve on the axis of
the wheel, long enough to reach to the lower level. This is furnished
with brazen buckets, each holding about a _congius_. Then by turning the
wheel, the chain also turns upon the axis and brings the buckets to the
top thereof, on passing which they are inverted and pour into the
conduits the water they have raised."
[15] This description certainly does not correspond in every particular
with the illustration.
[16] There is a certain deficiency in the hydraulics of this machine.
[17] The dimensions given in this description for the various members do
not tally.
[18] _Melibocian_,--the Harz.
[19] In the original text this is given as "lower," and appears to be an
error.
[20] Pliny (XXXI, 28). "In deep wells, the occurrence of _sulphurata_ or
_aluminosa_ vapor is fatal to the diggers. The presence of this peril is
shown if a lighted lamp let down into the well is extinguished. If so,
other wells are sunk to the right and left, which carry off these
noxious gases. Apart from these evils, the air itself becomes noxious
with depth, which can be remedied by constantly shaking linen cloths,
thus setting the air in motion."
[21] This is given in the German translation as _kobelt_. The _kobelt_
(or _cobaltum_ of Agricola) was probably arsenical-cobalt, a mineral
common in the Saxon mines. The origin of the application of the word
cobalt to a mineral appears to lie in the German word for the gnomes and
goblins (_kobelts_) so universal to Saxon miners' imaginations,--this
word in turn probably being derived from the Greek _cobali_ (mimes). The
suffering described above seems to have been associated with the
malevolence of demons, and later the word for these demons was attached
to this disagreeable ore. A quaint series of mining "sermons," by Johann
Mathesius, entitled _Sarepta oder Bergpostill_, Nuernberg, 1562, contains
the following passage (p. 154) which bears out this view. We retain the
original and varied spelling of cobalt and also add another view of
Mathesius, involving an experience of Solomon and Hiram of Tyre with
some mines containing cobalt.
"Sometimes, however, from dry hard veins a certain black, greenish, grey
or ash-coloured earth is dug out, often containing good ore, and this
mineral being burnt gives strong fumes and is extracted like 'tutty.' It
is called _cadmia fossilis_. You miners call it _cobelt_. Germans call
the Black Devil and the old Devil's furies, old and black _cobel_, who
injure people and their cattle with their witchcrafts. Now the Devil is
a wicked, malicious spirit, who shoots his poisoned darts into the
hearts of men, as sorcerers and witches shoot at the limbs of cattle and
men, and work much evil and mischief with _cobalt_ or _hipomane_ or
horses' poison. After quicksilver and _rotgueltigen_ ore, are _cobalt_
and _wismuth_ fumes; these are the most poisonous of the metals, and
with them one can kill flies, mice, cattle, birds, and men. So, fresh
_cobalt_ and _kisswasser_ (vitriol?) devour the hands and feet of
miners, and the dust and fumes of _cobalt_ kill many mining people and
workpeople who do much work among the fumes of the smelters. Whether or
not the Devil and his hellish crew gave their name to _cobelt_, or
_kobelt_, nevertheless, _cobelt_ is a poisonous and injurious metal even
if it contains silver. I find in I. Kings 9, the word _Cabul_. When
Solomon presented twenty towns in Galilee to the King of Tyre, Hiram
visited them first, and would not have them, and said the land was well
named _Cabul_ as Joshua had christened it. It is certain from Joshua
that these twenty towns lay in the Kingdom of Aser, not far from our
_Sarepta_, and that there had been iron and copper mines there, as Moses
says in another place. Inasmuch, then, as these twenty places were
mining towns, and _cobelt_ is a metal, it appears quite likely that the
mineral took its name from the land of Cabul. History and circumstances
bear out the theory that Hiram was an excellent and experienced miner,
who obtained much gold from Ophir, with which he honoured Solomon.
Therefore, the Great King wished to show his gratitude to his good
neighbour by honouring a miner with mining towns. But because the King
of Tyre was skilled in mines, he first inspected the new mines, and saw
that they only produced poor metal and much wild _cobelt_ ore, therefore
he preferred to find his gold by digging the gold and silver in India
rather than by getting it by the _cobelt_ veins and ore. For truly,
_cobelt_ ores are injurious, and are usually so embedded in other ore
that they rob them in the fire and consume (_madtet und frist_) much
lead before the silver is extracted, and when this happens it is
especially _speysig_. Therefore Hiram made a good reckoning as to the
mines and would not undertake all the expense of working and smelting,
and so returned Solomon the twenty towns."
[22] Pliny (XXXIII, 40). "Those employed in the works preparing
vermilion, cover their faces with a bladder-skin, that they may not
inhale the pernicious powder, yet they can see through the skin."
[23] _Pompholyx_ was a furnace deposit, usually mostly zinc oxide, but
often containing arsenical oxide, and to this latter quality this
reference probably applies. The symptoms mentioned later in the text
amply indicate arsenical poisoning, of which a sort of spherical effect
on the hands is characteristic. See also note on p. 112 for discussion
of "corrosive" _cadmia_; further information on _pompholyx_ is given in
Note 26, p. 394.
[24] Orcus, the god of the infernal regions,--otherwise Pluto.
[25] Caius Julius Solinus was an unreliable Roman Grammarian of the 3rd
Century. There is much difference of opinion as to the precise animal
meant by _solifuga_. The word is variously spelled _solipugus, solpugus,
solipuga, solipunga_, etc., and is mentioned by Pliny (VIII., 43), and
other ancient authors all apparently meaning a venomous insect, either
an ant or a spider. The term in later times indicated a scorpion.
[26] The presence of demons or gnomes in the mines was so general a
belief that Agricola fully accepted it. This is more remarkable, in view
of our author's very general scepticism regarding the supernatural. He,
however, does not classify them all as bad--some being distinctly
helpful. The description of gnomes of kindly intent, which is contained
in the last paragraph in _De Animantibus_ is of interest:--
"Then there are the gentle kind which the Germans as well as the Greeks
call cobalos, because they mimic men. They appear to laugh with glee and
pretend to do much, but really do nothing. They are called little
miners, because of their dwarfish stature, which is about two feet. They
are venerable looking and are clothed like miners in a filleted garment
with a leather apron about their loins. This kind does not often trouble
the miners, but they idle about in the shafts and tunnels and really do
nothing, although they pretend to be busy in all kinds of labour,
sometimes digging ore, and sometimes putting into buckets that which has
been dug. Sometimes they throw pebbles at the workmen, but they rarely
injure them unless the workmen first ridicule or curse them. They are
not very dissimilar to Goblins, which occasionally appear to men when
they go to or from their day's work, or when they attend their cattle.
Because they generally appear benign to men, the Germans call them
_guteli_. Those called _trulli_, which take the form of women as well as
men, actually enter the service of some people, especially the _Suions_.
The mining gnomes are especially active in the workings where metal has
already been found, or where there are hopes of discovering it, because
of which they do not discourage the miners, but on the contrary
stimulate them and cause them to labour more vigorously."
The German miners were not alone in such beliefs, for miners generally
accepted them--even to-day the faith in "knockers" has not entirely
disappeared from Cornwall. Neither the sea nor the forest so lends
itself to the substantiation of the supernatural as does the mine. The
dead darkness, in which the miners' lamps serve only to distort every
shape, the uncanny noises of restless rocks whose support has been
undermined, the approach of danger and death without warning, the sudden
vanishing or discovery of good fortune, all yield a thousand
corroborations to minds long steeped in ignorance and prepared for the
miraculous through religious teaching.
[27] The Plains of Laurentius extend from the mouth of the Tiber
southward--say twenty miles south of Rome. What Agricola's authority was
for silver mines in this region we cannot discover. This may, however,
refer to the lead-silver district of the Attic Peninsula, Laurion being
sometimes Latinized as _Laurium_ or _Laurius_.
BOOK VII.
Since the Sixth Book has described the iron tools, the vessels and the
machines used in mines, this Book will describe the methods of
assaying[1] ores; because it is desirable to first test them in order
that the material mined may be advantageously smelted, or that the dross
may be purged away and the metal made pure. Although writers have
mentioned such tests, yet none of them have set down the directions for
performing them, wherefore it is no wonder that those who come later
have written nothing on the subject. By tests of this kind miners can
determine with certainty whether ores contain any metal in them or not;
or if it has already been indicated that the ore contains one or more
metals, the tests show whether it is much or little; the miners also
ascertain by such tests the method by which the metal can be separated
from that part of the ore devoid of it; and further, by these tests,
they determine that part in which there is much metal from that part in
which there is little. Unless these tests have been carefully applied
before the metals are melted out, the ore cannot be smelted without
great loss to the owners, for the parts which do not easily melt in the
fire carry the metals off with them or consume them. In the last case,
they pass off with the fumes; in the other case they are mixed with the
slag and furnace accretions, and in such event the owners lose the
labour which they have spent in preparing the furnaces and the
crucibles, and further, it is necessary for them to incur fresh
expenditure for fluxes and other things. Metals, when they have been
melted out, are usually assayed in order that we may ascertain what
proportion of silver is in a _centumpondium_ of copper or lead, or what
quantity of gold is in one _libra_ of silver; and, on the other hand,
what proportion of copper or lead is contained in a _centumpondium_ of
silver, or what quantity of silver is contained in one _libra_ of gold.
And from this we can calculate whether it will be worth while to
separate the precious metals from the base metals, or not. Further, a
test of this kind shows whether coins are good or are debased; and
readily detects silver, if the coiners have mixed more than is lawful
with the gold; or copper, if the coiners have alloyed with the gold or
silver more of it than is allowable. I will explain all these methods
with the utmost care that I can.
The method of assaying ore used by mining people, differs from smelting
only by the small amount of material used. Inasmuch as, by smelting a
small quantity, they learn whether the smelting of a large quantity
will compensate them for their expenditure; hence, if they are not
particular to employ assays, they may, as I have already said, sometimes
smelt the metal from the ore with a loss or sometimes without any
profit; for they can assay the ore at a very small expense, and smelt
it only at a great expense. Both processes, however, are carried out in
the same way, for just as we assay ore in a little furnace, so do we
smelt it in the large furnace. Also in both cases charcoal and not wood
is burned. Moreover, in the crucible when metals are tested, be they
gold, silver, copper, or lead, they are mixed in precisely the same way
as they are mixed in the blast furnace when they are smelted. Further,
those who assay ores with fire, either pour out the metal in a liquid
state, or, when it has cooled, break the crucible and clean the metal
from slag; and in the same way the smelter, as soon as the metal flows
from the furnace into the forehearth, pours in cold water and takes the
slag from the metal with a hooked bar. Finally, in the same way that
gold and silver are separated from lead in a cupel, so also are they
separated in the cupellation furnace.
It is necessary that the assayer who is testing ore or metals should be
prepared and instructed in all things necessary in assaying, and that he
should close the doors of the room in which the assay furnace stands,
lest anyone coming at an inopportune moment might disturb his thoughts
when they are intent on the work. It is also necessary for him to place
his balances in a case, so that when he weighs the little buttons of
metal the scales may not be agitated by a draught of air, for that is a
hindrance to his work.
[Illustration 223a (Muffle Furnace): Round assay furnace.]
[Illustration 223b (Muffle Furnace): Rectangular assay furnace.]
[Illustration 224 (Muffle Assay Furnace): A--Openings in the plate.
B--Part of plate which projects beyond the furnace.]
Now I will describe the different things which are necessary in
assaying, beginning with the assay furnace, of which one differs from
another in shape, material, and the place in which it is set. In shape,
they may be round or rectangular, the latter shape being more suited to
assaying ores. The materials of the assay furnaces differ, in that one
is made of bricks, another of iron, and certain ones of clay. The one of
bricks is built on a chimney-hearth which is three and a half feet high;
the iron one is placed in the same position, and also the one of clay.
The brick one is a cubit high, a foot wide on the inside, and one foot
two digits long; at a point five digits above the hearth--which is
usually the thickness of an unbaked[2] brick--an iron plate is laid, and
smeared over with lute on the upper side to prevent it from being
injured by the fire; in front of the furnace above the plate is a mouth
a palm high, five digits wide, and rounded at the top. The iron plate
has three openings which are one digit wide and three digits long, one
is at each side and the third at the back; through them sometimes the
ash falls from the burning charcoal, and sometimes the draught blows
through the chamber which is below the iron plate, and stimulates the
fire. For this reason this furnace when used by metallurgists is named
from assaying, but when used by the alchemists it is named from the
wind[3]. The part of the iron plate which projects from the furnace is
generally three-quarters of a palm long and a palm wide; small pieces
of charcoal, after being laid thereon, can be placed quickly in the
furnace through its mouth with a pair of tongs, or again, if necessary,
can be taken out of the furnace and laid there.