De re metallica (1912)/Book III

by Georgius Agricola

BOOK III.

 

REVIOUSLY I have given much information concerning the miners, also I have discussed the choice of localities for mining, for washing sands, and for evaporating waters; further, I described the method of searching for veins. With such matters I was occupied in the second book; now I come to the third book, which is about veins and stringers, and the seams in the rocks^[1]. The term "vein" is sometimes used to indicate canales in the earth, but very often elsewhere by this name I have described that which may be put in vessels^[2]; I now attach a second significance to these words, for by them I mean to designate any mineral substances which the earth keeps hidden within her own deep receptacles.

First I will speak of the veins, which, in depth, width, and length, differ very much one from another. Those of one variety descend from the surface of the earth to its lowest depths, which on account of this characteristic, I am accustomed to call " venae profundae."

Another kind, unlike the venae profundae, neither ascend to the surface of the earth nor descend, but lying under the ground, expand over a large area; and on that account I call them "venae dilatatae."

Another occupies a large extent of space in length and width; therefore I usually call it vena cumulata,for it is nothing else than an accumulation of some certain kind of mineral, as I have described in the book

entitled De Subterraneorum Ortu et Causis. It occasionally happens, though it is unusual and rare, that several accumulations of this kind are found in one place, each one or more fathoms in depth and four or five in width, and one is distant from another two, three, or more fathoms. When the excavation of these accumulations begins, they at first appear in the shape of a disc; then they open out wider; finally from each of such

accumulations is usually formed a "vena cumulata."

The space between two veins is called an intervenium; this interval between the veins, if it is between venae dilatatae is entirely hidden underground. If, however, it lies between venae pro/undue then the top is plainly in sight, and the remainder is hidden.

Venae profundae differ greatly one from another in width, for some of them are one fathom wide, some are two cubits, others one cubit; others again are a foot wide, and some only half a foot; all of which our miners call wide veins. Others on the contrary, are only a palm wide, others three digits, or even two; these they call narrow. But in other places where there are very wide veins, the widths of a cubit, or a foot, or half a foot, are said to be narrow; at Cremnitz, for instance, there is a certain vein which measures in one place fifteen fathoms in width, in another eighteen, and in another twenty; the truth of this statement is vouched for by the inhabitants.

Venae dilatatae, in truth, differ also in thickness, for some are one fathom thick, others two, or even more; some are a cubit thick, some a foot, some only half a foot; and all these are usually called thick veins. Some on the other hand, are but a palm thick, some three digits, some two, some one; these are called thin veins.

Others, on the other hand, run from west to east.

Others run from south to north.

Others, on the contrary, run from north to south.

The seams in the rocks indicate to us whether a vein runs from the east or from the west. For instance, if the rock seams incline toward the westward as they descend into the earth, the vein is said to run from east to west; if they incline toward the east, the vein is said to run from west to east; in a similar manner, we determine from the rock seams whether the veins run north or south.

Now miners divide each quarter of the earth into six divisions; and by this method they apportion the earth into twenty-four directions, which they divide into two parts of twelve each. The instrument which indicates these directions is thus constructed. First a circle is made; then at equal intervals on one half portion of it right through to the other, twelve straight lines called by the Greeks διάμετροι , and in the Latin dimetientes, are drawn through a central point which the Greeks call κέιτρον, so that the circle is thus divided into twenty-four divisions, all being of an equal size. Then, within the circle are inscribed three other circles, the outermost of which has cross-lines dividing it into twenty-four equal parts; the space between it and the next circle contains two sets of twelve numbers, inscribed on the lines called "diameters"; while within the innermost circle it is hollowed out to contain a magnetic needle^[3] . The needle lies directly over that one of the twelve lines called "diameters" on which the number XII is inscribed at both ends.

When the needle which is governed by the magnet points directly from the north to the south, the number XII at its tail, which is forked, signifies the north, that number XII which is at its point indicates the south. The sign VI superior indicates the east, and VI inferior the west. Further, between each two cardinal points there are always five others which are not so important. The first two of these directions are called the prior directions; the last two are called the posterior, and the fifth direction lies immediately between the former and the latter; it is halved, and one half is attributed to one cardinal point and one half to the other. For example, between the northern number XII and the eastern number VI, are points numbered I, II, III, IV, V, of which I and II are northern directions lying toward the east, IV and V are eastern directions lying toward the north, and III is assigned, half to the north and half to the east.

One who wishes to know the direction of the veins underground, places over the vein the instrument just described; and the needle, as soon as it becomes quiet, will indicate the course of the vein. That is, if the vein proceeds from VI to VI, it either runs from east to west, or from west to east; but whether it be the former or the latter, is clearly shown by the seams in the rocks. If the vein proceeds along the line which is between V and VI toward the opposite direction, it runs from between the fifth and sixth divisions of east to the west, or from between the fifth and sixth divisions of west to the east; and again, whether it is the one or the other is clearly shown by the seams in the rocks. In a similar manner we determine the other directions.

Now miners reckon as many points as the sailors do in reckoning up the number of the winds. Not only is this done to-day in this country, but it was also done by the Romans who in olden times gave the winds partly Latin names and partly names borrowed from the Greeks. Any miner who pleases may therefore call the directions of the veins by the names of the winds. There are four principal winds, as there are four cardinal points: the Subsolanus, which blows from the east; and its opposite the Favonius, which blows from the west; the latter is called by the Greeks Ζέφυρος, and the former Ἀπηλιώτης. There is the Auster, which blows from the south; and opposed to it is the Septentrio, from the north; the former the Greeks called Νότος, and the latter Ἀπαρκτίας. There are also subordinate winds, to the number of twenty, as there are directions, for between each two principal winds there are always five subordinate ones. Between the Subsolanus (east wind) and the Auster (south wind) there is the Ornithiae or the Bird wind, which has the first place next to the Subsolanus; then comes Caecias; then Eurus, which lies in the midway of these five; next comes Vulturnus; and lastly, Euronotus, nearest the Auster (south wind). The Greeks have given these names to all of these, with the exception of Vulturnus, but those who do not distinguish the winds in so precise a manner say this is the same as the Greeks called Εὖρος. Between the Auster (south wind) and the Favonius (west wind) is first Altanus, to the right of the Auster (south wind); then Libonotus; then Africus, which is the middle one of these five; after that comes Subvesperus; next Argestes, to the left of Favonius (west wind). All these, with the exception of Libonotus and Argestes, have Latin names; but Africus also is called by the Greeks Λίψ. In a similar manner, between Favonius (west wind) and Septentrio (north wind), first to the right of Favonius (west wind), is the Etesiae; then Circius; then Caurus, which is in the middle of these five; then Corus; and lastly Thrascias to the left of Septentrio (north wind). To all of these, except that of Caurus, the Greeks gave the names, and those who do not distinguish the winds by so exact a plan, assert that the wind which the Greeks called Κόρος and the Latins Caurus is one and the same. Again, between Septentrio (north wind) and the Subsolanus (east wind), the first to the right of Septentrio (north wind) is Gallicus; then Supernas; then Aquilo, which is the middle one of these five; next comes Boreas; and lastly Carbas, to the left of Subsolanus (east wind). Here again, those who do not consider the winds to be in so great a multitude, but say there are but twelve winds in all, or at the most fourteen, assert that the wind called

by the Greeks Bοσίας and the Latins Aquilo is one and the same. For our purpose it is not only useful to adopt this large number of winds, but even to double it, as the German sailors do. They always reckon that between each two there is one in the centre taken from both. By this method we also are able to signify the intermediate directions by means of the names of the winds. For instance, if a vein runs from VI east to VI west, it is said to proceed from Subsolanus (east wind) to Favonius (west wind); but one which proceeds from between V and VI of the east to between V and VI west is said to proceed out of the middle of Carbas and Subsolanus to between Argestes and Favonius; the remaining directions, and their intermediates are similarly designated. The miner, on account of the natural properties of a magnet, by which the needle points to the south, must fix the instrument already described so that east is to the left and west to the right.

In a similar way to venae profundae, the venae dilatatae vary in their lateral directions, and we are able to understand from the seams in the rocks in which direction they extend into the ground. For if these incline toward the west in depth, the vein is said to extend from east to west; if on the contrary, they incline toward the east, the vein is said to go from west to east. In the same way, from the rock seams we can determine veins running south and north, or the reverse, and likewise to the subordinate directions and their intermediates.

Further, as regards the question of direction of a vena profunda, one runs straight from one quarter of the earth to that quarter which is opposite, while another one runs in a curve, in which case it may happen that a vein proceeding from the east does not turn to the quarter opposite, which is the west, but twists itself and turns to the south or the north.

Similarly some venae dilatatae are horizontal, some are inclined, and some are curved.

Also the veins which we call profundae differ in the manner in which they descend into the depths of the earth; for some are vertical (A), some are inclined and sloping (B), others crooked (C).

Moreover, venae profundae (B) differ much among themselves regarding the kind of locality through which they pass, for some extend along the slopes of mountains or hills (A-C) and do not descend down the sides.

Other Venae Profundae (D, E, F) from the very summit of the mountain or hill descend the slope (A) to the hollow or valley (B), and they again ascend the slope or the side of the mountain or hill opposite (C).

Other Venae Profundae (C, D) descend the mountain or hill (A) and extend out into the plain (B).

Some veins run straight along on the plateaux, the hills, or plains.

In the next place, venae profundae differ not a little in the manner in which they intersect, since one may cross through a second transversely, or one may cross another one obliquely as if cutting it in two.

If a vein which cuts through another principal one obliquely be the harder of the two, it penetrates right through it, just as a wedge of beech or iron can be driven through soft wood by means of a tool. If it be softer, the principal vein either drags the soft one with it for a distance of three feet, or perhaps one, two, three, or several fathoms, or else throws it forward along the principal vein; but this latter happens very rarely. But that the vein which cuts the principal one is the same vein on both sides, is shown by its having the same character in its foot walls and hanging walls.

Sometimes venae profundae join one with another, and from two or more outcropping veins^[4] , one is formed; or from two which do not outcrop one is made, if they are not far distant from each other, and the one dips into the other, or if each dips toward the other, and they thus join when they have descended in depth. In exactly the same way, out of three or more veins, one may be formed in depth.

However, such a junction of veins sometimes disunites and in this way it happens that the vein which was the right-hand vein becomes the left; and again, the one which was on the left becomes the right.

Furthermore, one vein may be split and divided into parts by some hard rock resembling a beak, or stringers in soft rock may sunder the vein and make two or more. These sometimes join together again and sometimes remain divided.

Whether a vein is separating from or uniting with another can be determined only from the seams in the rocks. For example, if a principal vein runs from the east to the west, the rock seams descend in depth likewise from the east toward the west, and the associated vein which joins with the principal vein, whether it runs from the south or the north, has its rock seams extending in the same way as its own, and they do not conform with the seams in the rock of the principal vein which remain the same after the junction unless the associated vein proceeds in the same direction as the principal vein. In that case we name the broader vein the principal one, and the narrower the associated vein. But if the principal vein splits, the rock seams which belong respectively to the parts, keep the same course when descending in depth as those of the principal vein.

But enough of venae profundae, their junctions and divisions. Now we come to venae dilatatae. A vena dllatata may either cross a vena profunda, or join with it, or it may be cut by a vena profunda, and be divided into parts.

Finally, a vena profunda has a "beginning" (origo), an "end" (finis), a "head" (caput), and a "tail" (cauda). That part whence it takes its rise is said to be its "beginning," that in which it terminates the "end." Its "head" ^[5]is that part which emerges into daylight; its "tail" that part which is hidden in the earth. But miners have no need to seek the "beginning" of veins, as formerly the kings of Egypt sought for the source of the Nile, but it is enough for them to discover some other part of the vein and to recognise ito direction, for seldom can either the "beginning" or the "end" be found. The direction in which the head of the vein comes into the light, or the direction toward which the tail extends, is indicated by its footwall and hangingwall. The latter is said to hang, and the former to lie. The vein rests on the footwall, and the hangingwall overhangs it; thus, when we descend a shaft, the part to which we turn the face is the footwall and seat of the vein, that to which we turn the back is the hangingwall. Also in another way, the head accords with the footwall and the tail with the hangingwall, for if the footwall is toward the south, the vein extends its head into the light toward the south; and the hangingwall, because it is always opposite to the footwall, is then toward the north. Consequently the vein extends its tail toward the north if it is an inclined vena profunda. Similarly, we can determine with regard to east and west and the subordinate and their intermediate directions. A vena profunda which descends into the earth may be either vertical, inclined, or crooked the footwall of an inclined vein is easily distinguished from the hangingwall, but it is not so with a vertical vein; and again, the footwall of a crooked vein is inverted and changed into the hangingwall, and contrariwise the hangingwall is twisted into the footwall, but very many of these crooked veins may be turned back to vertical or inclined ones.

A vena dilatata has only a "beginning" and an "end," and in the place of the "head" and "tail" it has two sides.

A vena cumulata has a "beginning," an "end," a "head," and a "tail," just as a vena profunda. Moreover, a vena cumulata, and likewise a vena dilatata, are often cut through by a transverse vena profunda.

Stringers (fibrae)^[6], which are little veins, are classified into fibrae transversae, fibrae obliquae which cut the vein obliquely, fibrae sociae, fibrae dilatatae, and fibrae incumbentes. The fibra transversa crosses the vein; the fibra obligua crosses the vein obliquely; the fibra socta joins with the vein itself; the fibra dilatata, like the vena dilatata, penetrates through it; but the fibra dilatata, as well as the fibra profunda, is usually found associated with a vein.

The fibra incumbens does not descend as deeply into the earth as the other stringers, but lies on the vein, as it were, from the surface to the hangingwall or footwall, from which it is named Subdialis.^[7]

In truth, as to direction, junctions, and divisions, the stringers are not different from the veins.

Lastly, the seams, which are the very finest stringers (fibrae), divide the rock, and occur sometimes frequently, sometimes rarely. From whatever direction the vein comes, its seams always turn their heads toward the light in the same direction. But, while the seams usually run from one point of the compass to another immediately opposite it, as for instance, from east to west, if hard stringers divert them, it may happen that these very seams, which before were running from east to west, then contrariwise proceed from west to east, and the direction of the rocks is thus inverted. In such a case, the direction of the veins is judged, not by the direction of the seams which occur rarely, but by those which constantly recur.

Both veins or stringers may be solid or drusy, or barren of minerals, or pervious to water. Solid veins contain no water and very little air. The drusy veins rarely contain water; they often contain air. Those which are barren of minerals often carry water. Solid veins and stringers consist sometimes of hard materials, sometimes of soft, and sometimes of a kind of medium between the two.

But to return to veins. A great number of miners consider^[8] that the best veins in depth are those which run from the VI or VII direction of the east to the VI or VII direction of the west, through a mountain slope which inclines to the north; and whose hangingwalls are in the south, and whose footwalls are in the north, and which have their heads rising to the north, as explained before, always like the footwall, and finally, whose rock seams turn their heads to the east. And the veins which are the next best are those which, on the contrary, extend from the VI or VII direction of the west to the VI or VII direction of the east, through the slope of a mountain which similarly inclines to the north, whose hangingwalls are also in the south, whose footwalls are in the north, and whose heads rise toward the north; and lastly, whose rock seams raise their heads toward the west. In the third place, they recommend those veins which extend from XII north to XII south, through the slope of a mountain which faces east; whose hangingwalls are in the west, whose footwalls are in the east; whose heads rise toward the east; and whose rock seams raise their heads toward the north.

Therefore they devote all their energies to those veins, and give very little or nothing to those whose heads, or the heads of whose rock seams rise toward the south or west. For although they say these veins sometimes show bright specks of pure metal adhering to the stones, or they come upon lumps of metal, yet these are so few and far between that despite them it is not worth the trouble to excavate such veins; and miners who persevere in digging in the hope of coming upon a quantity of metal, always lose their time and trouble. And they say that from veins of this kind, since the sun’s rays draw out the metallic material, very little metal is gained. But in this matter the actual experience of the miners who thus judge of the veins does not always agree with their opinions, nor is their reasoning sound; since indeed the veins which run from east to west through the slope of a mountain which inclines to the south, whose heads rise likewise to the south, are not less charged with metals, than those to which miners are wont to accord the first place in productiveness; as in recent years has been proved by the St. Lorentz vein at Abertham, which our countrymen call Gottsgaab, for they have dug out of it a large quantity of pure silver;. and lately a vein in Annaberg, called by the name of Himmelsch hoz^[9], has made it plain by the production of much silver that veins which extend from the north to the south, with their heads rising toward the west, are no less rich in metals than those whose heads rise toward the east.

It may be denied that the heat of the sun draws the metallic material out of these veins; for though it draws up vapours from the surface of the ground, the rays of the sun do not penetrate right down to the depths; because the all’of a tunnel which is covered and enveloped by solid earth to the depth of only two fathoms is cold in summer, for the intermediate earth holds in check the force of the sun. Having observed this fact, the inhabitants and dwellers of very hot regions lie down by day in caves which protect them from the excessive ardour of the sun. Therefore it is unlikely that the sun draws out from within the earth the metallic bodies. Indeed, it cannot even dry the moisture of many places abounding in veins, because they are protected and shaded by the trees. Furthermore, certain miners, out of all the different kinds of metallic veins, choose those which I have described, and others, on the contrary, reject copper mines which are of this sort, so that there seems to be no reason in this. For what can be the reason if the sun draws no copper from copper veins, that it draws silver from silver veins, and gold from gold veins?

Moreover, some miners, of whose number was Calbus^[10] , distinguish between the gold-bearing rivers and streams. A river, they say, or a stream, is most productive of fine and coarse grains of gold when it comes from the east and flows to the west, and when it washes against the foot of mountains which are situated in the north, and when it has a level plain toward the south or west. In the second place, they esteem a river or a stream which flows in the opposite course from the west toward the east, and which has the mountains to the north and the level plain to the south. In the third place, they esteem the river or the stream which flows from the north to the south and washes the base of the mountains which are situated in the east. But they say that the river or stream is least productive of gold which flows in a contrary direction from the south to the north, and washes the base of mountains which are situated in the west. Lastly, of the streams or rivers which flow from the rising sun toward the setting sun, or which flow from the northern parts to the southern parts, they favour those which approach the nearest to the lauded ones, and say they are more productive of gold, and the further they depart from them the less productive they are. Such are the opinions held about rivers and streams. Now, since gold is not generated in the rivers and streams, as we have maintained against Albertus^[11] in the book entitled "De Subterraneorum Ortu et Causis," Book V, but is torn away from the veins and stringers and settled in the sands of torrents and water-courses, in whatever direction the rivers or streams flow, therefore it is reasonable to expect to find gold therein; which is not opposed by experience. Nevertheless, we do not deny that gold is generated in veins and stringers which lie under the beds of rivers or streams, as in other places.

1. Modern nomenclature in the description of ore-deposits is so impregnated with modern views of their origin, that we have considered it desirable in many instances to adopt the Latin terms used by the author, for we believe this method will allow the reader greater freedom of judgment as to the author’s views. The Latin names retained are usually expressive even to the non-Latin student. In a general way, a vena profunda is a fissure vein, a vena dilatata is a bedded deposit, and a vena cumulata an impregnation, or a replacement or a stockwerk. The canales, as will appear from the following footnote, were ore channels. " The seams of the rocks" (commissurae saxorum) are very puzzling. The author states, as appears in the following note, that they are of two kinds, contemporaneous with the formation of the rocks, and also of the nature of veinlets. However, as to their supposed relation to the strike of veins, we can offer no explanation. There are passages in this chapter where if the word "ore-shoot" were introduced for "seams in the rocks" the text would be intelligible. That is, it is possible to conceive the view that the determination of whether an east-west vein ran east or ran west was dependent on the dip of the ore-shoot along the strike. This view, however, is utterly impossible to reconcile with the description and illustration of commissurae saxorum given on page 54, where they are defined as the finest stringers. The following passage from the Nutzliche Bergbuchlin (see Appendix), reads very much as though the dip of ore-shoots was understood at this time in relation to the direction of veins. " Every vein (gang) has two (outcrops) ausgehen, one of the ’ ausgehen is toward daylight along the whole length of the vein, which is called the ausgehen ’ of the whole vein. The other ausgehen is contrary to or toward the strike (slreichen) of ’ the vein, according to its rock (gestein), that is called the gesteins ausgehen; for instance, ’ every vein that has its strike from east to west has its gesleins ausgehen to the east, and ’ vice-versa," Agricola’s classification of ore-deposits, after the general distinction between alluvial and in situ deposits, is based entirely upon form, as will be seen in the quotation below relating to the origin of canales. The German equivalents in the Glossary are as follows:

   Fissure vein (vena profunda)	Gang.
   Bedded deposit (vena dilatata)	Schwebender gang oder fletze.
   Stockwerk or impregnation (vena cumulata)	Geschute oder stock.
   Stringer (fibra)	Klufft.
   Seams or joints (commissurae saxorum)	Absetzen des gesteins.

   It is interesting to note that in De Natura Fossilium he describes coal and salt, and later in De Re Metallica he describes the Mannsfeld copper schists, as all being venae dilatatae. This nomenclature and classification is not original with Agricola. Pliny (xxxm, 21) uses the term vena with no explanations, and while Agricola coined the Latin terms for various kinds of veins, they are his transliteration of German terms already in use. The Nutzliche Bergbuchlin gives this same classification.

   Historical Note on the Theory of Ore Deposits. Prior to Agricola there were three schools of explanation of the phenomena of ore deposits, the orthodox followers of the Genesis, the Greek Philosophers, and the Alchemists. The geology of the Genesis the contemporaneous formation of everything needs no comment other than that for anyone to have proposed an alternative to the dogma of the orthodox during the Middle Ages, required much independence of mind. Of the Greek views which are meagre enough that of the Peripatetics greatly dominated thought on natural phenomena down to the iyth century.

   Aristotle's views may be summarized : The elements are earth, water, air, and fire ; they are transmutable and never found pure, and are endowed with certain funda- mental properties which acted as an "efficient" force upon the material cause the elements.

   These properties were dryness and dampness and heat and cold, the latter being active, the former passive. Further, the elements were possessed of weight and lightness, for instance earth was absolutely heavy, fire absolutely light. The active and passive proper- ties existed in binary combinations, one of which is characteristic, i.e., " earth " is cold and dry, water damp and cold, fire hot and dry, air hot and wet ; transmutation took place, for instance, by removing the cold from water, when air resulted (really steam), and by removing the dampness from water, when " earth " resulted (really any dissolved substance). The transmutation of the elements in the earth (meaning the globe) produces two " exhalations," the one fiery (probably meaning gases), the other damp (probably meaning steam). The former produces stones, the latter the metals. Theophrastus (On Stones, I to vn.) elaborates the views of Aristotle on the origin of stones, metals, etc. : " Of things " formed in the earth some have their origin from water, others from earth. Water is the " basis of metals, silver, gold, and the rest ; ' earth ' of stones, as well the more precious " as the common. . . . All these are formed by solidification of matter pure and " equal in its constituent parts, which has been brought together in that state by mere " afflux or by means of some kind of percolation, or separated. . . . The solidification " is in some of these substances due to heat and in others to cold." (Based on Hill's Trans., pp. 3-11). That is, the metals inasmuch as they become liquid when heated must be in a large part water, and, like water, they solidify with cold. Therefore, the " metals are cold and damp." Stones, on the other hand, solidify with heat and do not liquefy, therefore, they are " dry and hot " and partake largely of " earth." This " earth" was something indefinite, but purer and more pristine than common clay. In discussing the ancient beliefs with regard to the origin of deposits, we must not overlook the import of the use of the word "vein" (vena) by various ancient authors including Pliny (xxxm, 21), although he offers no explanation of the term.

   During the Middle Ages there arose the horde of Alchemists and Astrologers, a review of the development of whose muddled views is but barren reading. In the main they held more or less to the Peripatetic view, with additions of their own. Geber (i3th (?) century, see Appendix B) propounded the conception that all metals were composed of varying proportions of " spiritual " sulphur and quicksilver, and to these Albertus Magnus added salt.' The Astrologers contributed the idea that the immediate cause of the metals were the various planets. The only work devoted to description of ore-deposits prior to Agricola was the Bergbiichlin (about 1,520, see Appendix B), and this little book exhibits the absolute apogee of muddled thought derived from the Peripatetics, the Alchemists, and the Astrologers. We believe it is of interest to reproduce the following statement, if for no other reason than to indicate the great advance in thought shown by Agricola.

   " The first chapter or first part ; on the common origin of ore, whether silver, gold, " tin, copper, iron, or lead ore, in which they all appear together, and are called by the common " name of metallic ore. It must be noticed that for the washing or smelting of metallic ore, " there must be the one who works and the thing that is worked upon, or the material upon " which the work is expended. The general worker (efficient force) on the ore and on all " things that are born, is the heavens, its movement, its light and influences, as the " philosophers say. The influence of the heavens is multiplied by the movement of the "' firmaments and the movements of the seven planets. Therefore, every metallic ore ' receives a special influence from its own particular planet, due to the properties of the ' planet and of the ore, also due to properties of heat, cold, dampness, and dryness. Thus ' gold is of the Sun or its influence, silver of the Moon, tin of Jupiter, copper of Venus, iron ' of Mars, lead of Saturn, and quicksilver of Mercury. Therefore, metals are often called by ' these names by hermits and other philosophers. Thus gold is called the Sun, in Latin Sol, ' silver is called the Moon, in Latin Luna, as is clearly stated in the special chapters on each ' metal. Thus briefly have we spoken of the ' common worker ' of metal and ore. But the ' thing worked upon, or the common material of all metals, according to the opinion of ' the learned, is sulphur and quicksilver, which through the movement and influence of the ' heavens must have become united and hardened into one metallic body or one ore.

   ' Certain others hold that through the movement and the influence of the heavens, vapours ' or braden, called mineral exhalations, are drawn up from the depths of the earth, from " sulphur and quicksilver, and the rising fumes pass into the veins and stringers and are

   united through the effect of the planets and made into ore. Certain others hold that metal is not formed from quicksilver, because in many places metallic ore is found and no quicksilver. But instead of quicksilver they maintain a damp and cold and slimy material is set up on all sulphur which is drawn out from the earth, like your perspiration, and from that mixed with sulphur all metals are formed. Now each of these opinions is correct according to a good understanding and right interpretation; the ore or metal is formed from the fattiness of the earth as the material of the first degree (primary element), also the vapours or braden on the one part and the materials on the other part, both of which are called quicksilver. Likewise in the mingling or union of the quicksilver and the sulphur in the ore, the sulphur is counted the male and quicksilver the female, as in the bearing or conception of a child. Also the sulphur is a special worker in ore or metal. The second chapter or part deals with the general capacity of the mountain. Although the influence of the heavens and the fitness of the material are necessary to the formation of ore or metal, yet these are not enough thereto. But there must be adaptability of the natural vessel in which the ore is formed, such are the veins, namely sleinendegange, flachgange, schargange, creutzgange, or as these may be termed in provincial names. Also the mineral force must have easy access to the natural vessel such as through the kluffte (stringers), namely hengkluft, querklufte, flachekluffte, creutzklufft, and other occasional flotzwerk, according to their various local names. Also there must be a suitable place in the mountain which the veins and stringers can traverse.AGRICOLA’S VIEWS ON THE ORIGIN OF ORE DEPOSITS. Agricola rejected absolutely the Biblical view which, he says, was the opinion of the vulgar; further, he repudiates the alchemistic and astrological view with great vigour. There can be no doubt, however, that he was greatly influenced by the Peripatetic philosophy. He accepted absolutely the four elements earth, fire, water, and air, and their binary properties, and the theory that every substance had a material cause operated upon by an efficient force. Beyond this he did not go, and a large portion of De Ortu et Causis is devoted to disproof of the origin of metals and stones from the Peripatetic exhalations.No one should conclude that Agricola’s theories are set out with the clarity of Darwin or Lyell. However, the matter is of such importance in the history of the theory of oredeposits, and has been either so ignored or so coloured by the preconceptions of narrators, that we consider it justifiable to devote the space necessary to a reproduction of his own statements in De Ortu et Causis and other works. Before doing so we believe it will be of service to readers to summarize these views, and in giving quotations from the Author’s other works, to group them under special headings, following the outline of his . theory given below. His theory was:

   1. Openings in the earth (canales) were formed by the erosion of subterranean waters.
   2. These ground waters were due (a) to the infiltration of the surface waters, rain, river, and sea water; (6) to the condensation of steam (halitus) arising from the penetration of the surface waters to greater depths, the production of this halitus being due to subterranean heat, which in his view was in turn due in the main to burning bitumen (a comprehensive genera which embraced coal).
   3. The filling of these canales is composed of earth,solidified juices,stone,metals, and compounds,all deposited from water and juices circulating in the canales. (See also note 4, page i).

   Earth comprises clay, mud, ochre, marl, and peculiar earths generally. The origin of these earths was from rocks, due to erosion, transportation, and deposition by water. Solidified juices (sued concreti) comprised salt, soda, vitriol, bitumen, etc., being generally those substances which he conceived were soluble in and deposited from water. Stones comprised precious, semi-precious, and unusual stones, such as quartz, fluor-spar, etc., as distinguished from country rock; the origin of these he attributed in minor proportion to transportation of fragments of rock, but in the main to deposits from ordinary mineral juice and from "stone juice(succuslapidescens). Metals comprised the seven traditional metals; the compounds comprised the metallic minerals; and both were due to deposition from juices, the compounds being due to a mixture of juices. The juices play the most important part in Agricola’s theory. Each substance had its own particular juice, and in his theory every substance had a material and an efficient cause, the first being the juice, the second being heat or cold. Owing to the latter the juices fell into two categories those solidified by heat (i.e., by evaporation, such as salt), and those solidified by cold, (i.e, because metals melt and flow by heat, therefore their solidification was due to cold, and the juice underwent similar treatment). As to the origin of these juices, some were generated by the solution of their own particular substance, but in the main their origin was due to the combination of "dry things," such as "earth," with water, the mixture being heated, and the resultant metals depended upon the proportions of "earth" and water. In some cases we have been inclined to translate succus (juice) as "solution," but in other cases it embraced substances to which this would not apply, and we feared implying in the text a chemical understanding not warranted prior to the atomic theory. In order to distinguish between earths, (clays, etc.,) the Peripatetic "earth" (a pure element) and the earth (the globe) we have given the two former in quotation marks. There is no doubt some confusion between earth (clays, etc.) and the Peripatetic "earth," as the latter was a pure substance not found in its pristine form in nature; it is, however, difficult to distinguish between the two.

   Origin of Canales (De Ortu, p. 35). I now come to the canales in the earth. These are veins, veinlets, and what are called ’seams in the rocks.’ These serve as vessels or receptacles for the material from which minerals (res fossiles) are formed. The term vena is most frequently given to what is contained in the canales, but likewise the same name is applied to the canales themselves. The term vein is borrowed from that used for animals, for just as their veins are distributed through all parts of the body, and just as by means of the veins blood is diffused from the liver throughout the whole body, so also the veins traverse the whole globe, and more particularly the mountainous districts; and water runs and flows through them. With regard to veinlets or stringers and ’seams in the rocks,’ which are the thinnest stringers, the following is the mode of their arrangement. Veins in the earth, just like the veins of an animal, have certain veinlets of their own, but in a contrary way. For the larger veins of animals pour blood into the veinlets, while in the earth the humours are usually poured from the veinlets into the larger veins, and rarely flow from the larger into the smaller ones. As for the seams in the rocks (commissurae saxorum) we consider that they are produced by two methods: by the first, which is peculiar to themselves, they are formed at the same time as the rocks, for the heat bakes the refractory material into stone and the non-refractory material similarly heated exhales its humours and is made into ’earth,’ generally friable. The other method is common also to veins and veinlets, when water is collected into one place it softens the rock by its liquid nature, and by its weight and pressure breaks and divides it. Now, if the rock is hard, it makes seams in the rocks and veinlets, and if it is not too hard it makes veins. However, if the rocks are not hard, seams and veinlets are created as well as veins. If these do not carry a very large quantity of water, or if they are pressed by a great volume of it, they soon discharge themselves into the nearest veins. The following appears to be the reason why some veinlets or stringers and veins are profundae and others dilatatae. The force of the water crushes and splits the brittle rocks; and when they are broken and split, it forces its way through them and passes on, at one time in a downward direction, making small and large venae profundae, at another time in a lateral direction, in which way venae dilatatae are formed. Now since in each class there are found some which are straight, some inclined, and some crooked, it should be explained that the water makes the vena profunda straight when it runs straight downward, inclined when it runs in an inclined direction; and that it makes a vena dilatata straight when it runs horizontally to the right or left, and in a similar way inclined when it runs in a sloping direction. Stringers and large veins of the profunda sort, extending for considerable lengths, become crooked from two causes. In one case when narrow veins are intersected by wide ones, then the latter bend or drag the former a little. In the other case, when the water runs against very hard rock, being unable to break through, it goes around the nearest way, and the stringers and veins are formed bent and crooked. This last is also the reason we sometimes see crooked small and large venae dilatatae, not unlike the gentle rise and fall of flowing water. Next, venae profundae are wide, either because of abundant water or because the rock is fragile. On the other hand, they are narrow, either because but little water flows and trickles through them, or because the rock is very hard. The venae dilatatae, too, for the same reasons, are either thin or thick. There are other differences, too, in stringers and veins, which I will explain in my work De Re Metallica. . . . There is also a third kind of vein which, as it cannot be described as a wide vena profunda, nor as a thick vena dilatata, we will call a vena cumulata. These are nothing else than places where some species of mineral is accumulated; sometimes exceeding in depth and also in length and breadth 600 feet; sometimes, or rather generally, not so deep nor so long, nor so wide. These are created when water has broken away the rock for such a length, breadth, and thickness, and has flung aside and ejected the stones and sand from the great cavern which is thus made; and afterward when the mouth is obstructed and closed up, the whole cavern is filled with material from which there is in time produced some one or more minerals. Now I have stated when discoursing on the origin of subterranean humours, that water erodes away substances inside the earth, just as it does those on the surface, and least of all does it shun minerals; for which reason we may daily see veinlets and veins sometimes filled with all’and water, but void and empty of mining products, and sometimes full of these same materials. Even those which are empty of minerals become finally obstructed, and when the rock is broken through at some other point the water gushes out. It is certain that old springs are closed up in some way and new ones opened in others. In the same manner, but much more easily and quickly than in the solid rock, water produces stringers and veins in surface material, whether it be in plains, hills, or mountains. Of this kind are the stringers in the banks of rivers which produce gold, and the veins which produce peculiar earth. So in this manner in the earth are made canales which bear minerals."

   Origin of Ground Waters. (De Ortu p. 5). .... Besides rain there is another kind of water by which the interior of the earth is soaked, so that being heated it can continually give off halitus, from which arises a great and abundant force of waters." In description of the modus operandi of halitum, he says (p. 6): . . . . Halitus rises to the upper parts of the canales, where the congealing cold turns it into water, which by its gravity and weight again runs down to the lowest parts and increases the flow of water if there is any. If any finds its way through a canales dilatata the same thing happens, but it is carried a long way from its place of origin. The first phase of distillation teaches us how this water is produced, for when that which is put into the ampulla is warmed it evaporates (expirare), and this halitus rising into the operculum is converted by cold into water, which drips through the spout. In this way water is being continually created underground." (De Ortu, p. 7): And so we know from all this that of the waters which are under the earth, some are collected from rain, some arise from halitus (steam), some from river-water, some from sea-water; and we know that the halitum is produced within the earth partly from rain-water, partly from river-water, and partly from sea-water." It would require too much space to set out Agricola’s views upon the origin of the subterranean heat which produced this steam. It is an involved theory embracing clashing winds, burning bitumen, coal, etc., and is fully set out in the latter part of Book II, De Ortu et Causis.

   Origin of Gangue Minerals. It is necessary to bear in mind that Agricola divided minerals (res fossiles Things dug up, " see note 4, p. i) into earths," solidified juices, " stones," metals, " and compounds; and, further, to bear in mind that in his conception of the origin of things generally, he was a disciple of the Peripatetic logic of a material substance and an efficient force, " as mentioned above.

   As to the origin of earths," he says (De Ortu, p. 38): Pure and simple-’earth’ originates in the canales in the following way: rain water, which is absorbed by the surface of the earth, first of all penetrates and passes into the inner parts of the earth and mixes with it; next, it is collected from all sides into stringers and veins, where it, and sometimes water of other origin, erodes the ’earth’ away, a great quantity of it if the stringers and veins are in ’earth,’ a small quantity if they are in rock. The softer the rock is, the more the water wears away particles by its continual movement. To this class of rock belongs limestone, from which we see chalk, clay, and marl, and other unctuous ’earths’ made; also sandstone, from which are made those barren ’earths’ which we may see in ravines and on bare rocks. For the rain softens limestone or sandstone and carries particles away with it, and the sediment collects together and forms mud, which afterward solidifies into some kind of ’earth.’ In a similar way under the ground the power of water softens the rock and dissolves the coarser fragments of stone. This is clearly shown by the following circumstance, that frequently the powder of rock or marble is found in a soft state and as if partly dissolved. Now, the water carries this mixture into the course of some underground canalis, or dragging it into narrow places, filters away. And in each case the water flows away and a pure and uniform material is left from which ’earth’ is made. . . . Particles of rock, however, are only by force of long time so softened by water as to become similar to particles of ’earth.’ It is possible to see ’earth’ being made in this way in underground canales in the earth, when drifts or tunnels are driven into the mountains, or when shafts are sunk, for then the canales are laid bare; also it can be seen above ground in ravines, as I have said, or otherwise disclosed. For in both cases it is clear to the eye that they are made out of the ’earth’ or rocks, which are often of the same colour. And in just the same way they are made in the springs which the veins discharge. Since all those things which we see with our eyes and which are perceived with our senses, are more clearly understood than if they were learnt by means of reasoning, we deem it sufficient to explain by this argument our view of the origin of ’earth.’ In the manner which I have described, ’earths’ originate in veins and veinlets, seams in the rocks, springs, ravines, and other openings, therefore all ’earths’ are made in this way. As to those that are found in underground canales which do not appear to have been derived from the earth or rock adjoining, these have undoubtedly been carried by the water for a greater distance from their place of origin; which may be made clear to anyone who seeks their source."

   On the origin of solidified juices he states (De Ortu, p. 43): "I will now speak of solidified juices (sued concreti). I give this name to those minerals which are without difficulty resolved into liquids (humore). Some stones and metals, even though they are themselves composed of juices, have been compressed so solidly by the cold that they can only be dissolved with difficulty or not at all. . . . For juices, as I said above, are either made when dry substances immersed in moisture are cooked by heat, or else they are made when water flows over ’earth,’ or when the surrounding moisture corrodes metallic material; or else they are forced out of the ground by the power of heat alone. Therefore, solidified juices originate from liquid juices, which either heat or cold have condensed. But that which heat has dried, fire reduces to dust, and moisture dissolves. Not only does warm or cold water dissolve certain solidified juices, but also humid air; and a juice which the cold has condensed is liquefied by fire and warm water. A salty juice is condensed into salt; a bitter one into soda; an astringent and sharp one into alum or into vitriol. Skilled workmen in a similar way to nature, evaporate water which contains juices of this kind until it is condensed; from salty ones they make salt, from aluminous ones alum, from one which contains vitriol they make vitriol. These workmen imitate nature in condensing liquid juices with heat, but they cannot imitate nature in condensing them by cold. From an astringent juice not only is alum made and vitriol, but also sory, chalcilis, and misy, which appears to be the ’flower’ of vitriol, just as melanteria is of sory. (See note on p. 573 for these minerals.) When humour corrodes pyrites so that it is friable, an astringent juice of this kind is obtained."

   On the Origin of Stones (De Ortu, p. 50), he states: "It is now necessary to review in a few words what I have said as to all of the material from which stones are made; there is first of all mud; next juice which is solidified by severe cold; then fragments of rock; afterward stone juice (succuslapidescens), which also turns to stone when it comes out into the air; and lastly, everything which has pores capable of receiving a stony juice." As to an "efficient force," he states (p. 54): "But it is now necessary that I should explain my own view, omitting the first and antecedent causes. Thus the immediate causes are heat and cold; next in some way a stony juice. For we know that stones which water has dissolved, are solidified when dried by heat; and on the contrary, we know that stones which melt by fire, such as quartz, solidify by cold. For solidification and the conditions which are opposite thereto, namely, dissolving and liquefying, spring from causes which are the opposite to each other. Heat, driving the water (humorem) out of a substance, makes it hard; and cold, by withdrawing the air, solidifies the same stone firmly. But if a stony juice, either alone or mixed with water, finds its way into the pores either of plants or animals .... it creates stones. ... If stony juice is obtained in certain stony places and flows through the veins, for this reason certain springs, brooks, streams, and lakes, have the power of turning things to stone."

   On the Origin of Metals, he says (De Ortu, p. 71): " Having now refuted the opinions of others, I must explain what it really is from which metals are produced. The best proof that there is water in their materials is the fact that they flow when melted, whereas they are again solidified by the cold of all’or water. This, however, must be understood in the sense that there is more water in them and less ’earth ’; for it is not simply water that is their substance but water mixed with ’ earth.’ And such a proportion of ’ earth ’ is in the mixture as may obscure the transparency of the water, but not remove the brilliance which is frequently in unpolished things. Again, the purer the mixture, the more precious the metal which is made from it, and the greater its resistance to fire. But what proportion of ’ earth ’ is in each liquid from which a metal is made no mortal can ever ascertain, or still less explain, but the one God has known it, Who has given certain sure and fixed laws to nature for mixing and blending things together. It is a juice (succus) then, from which metals are formed; and this juice is created by various operations. Of these operations the first is a flow of water which softens the ’earth’or carries the ’earth’along with it, thus there is a mixture of ’ earth ’ and water, then the power of heat works upon the mixtures so as to produce that kind of a juice. We have spoken of the substance of metals; we must now speak of their efficient cause. . . (P- 75): We d not deny the statement of Albertus Magnus that the mixture of ’earth’and water is baked by subterranean heat to a certain denseness, but it is our opinion that the juice so obtained is afterward solidified by cold so as to become a metal. . . . We grant, indeed, that heat is the efficient cause of a good mixture of elements, and also cooks this same mixture into a juice, but until this juice is solidified by cold it is not a metal." ... (p. 76): This view of Aristotle is the true one. For metals melt through the heat and somehow become softened; but those which have become softened through heat are again solidified by the influence of cold, and, on the contrary, those which become softened by moisture are solidified by heat.

   On the Origin of Compounds, he states (De Ortu, p. 80): " There now remain for our consideration the compound minerals (mistae), that is to say, minerals which contain either solidified juice (succus concretus) and ’ stone,’ or else metal or metals and ’ stone,’ or else metal-coloured ’ earth,’ of which two or more have so grown together by the action of cold that one body has been created. By this sign they are distin- guished from mixed minerals (composita), for the latter have not one body. For example, pyrites, galena, and ruby silver are reckoned in the category of compound minerals, whereas we say that metallic ’ earths ’ or stony ’ earths ’ or ’ earths ’ mingled with juices, are mixed minerals; or similarly, stones in which metal or solidified juices adhere, or which contain ’ earth.’ But of both these classes I will treat more fully in my book De Natura Fossilium. I will now discuss their origin in a few words. A compound mineral is produced when either a juice from which some metal is obtained, or a humour and some other juice from which stone is obtained, are solidified by cold, or when two or more juices of different metals mixed with the juice from which stone is made, are condensed by the same cold, or when a metallic juice is mixed with ’earth ’ whose whole mass is stained with its colour, and in this way they form one body. To the first class belongs galena, composed of lead juice and of that material which forms the substance of opaque stone. Similarly, transparent ruby silver is made out of silver juice and the juice which forms the substance of transparent stone; when it is smelted into pure silver, since from it is separated the transparent juice, it is no longer transparent. Then too, there is pyrites, or lapis fissilis, from which sulphur is melted. To the second kind belongs that kind of pyrites which contains not only copper and stone, but sometimes copper, silver, and stone; sometimes copper, silver, gold, and stone; sometimes silver, lead, tin, copper and silver glance. That compound minerals consist of stone and metal is sufficiently proved by their hardness; that some are made of ’ earth ’ and metal is proved from brass, which is composed of copper and calamine; and also proved from white brass, which is coloured by artificial white arsenic. Sometimes the heat bakes some of them to such an extent that they appear to have flowed out of blazing furnaces, which we may see in the case of cadmia and pyrites. A metallic substance is produced out of ’ earth ’ when a metallic juice impregnating the ’ earth ’ solidifies with cold, the ’ earth ’ not being changed. A stony substance is produced when viscous and non-viscous ’ earth ’ are accumulated in one place and baked by heat; for then the viscous part turns into stone and the non- viscous is only dried up."

   The Origin of Juices. The portion of Agricola’s theory surrounding this subject is by no means easy to follow in detail, especially as it is difficult to adjust one’s point of view to the Peripatetic elements, fire, water, earth, and air, instead of to those of the atomic theory which so dominates our every modern conception. That Agricola’s ’ juice ’ was in most cases a solution is indicated by the statement (De Ortu, p. 48): " Nor is juice anything but water, which on the other hand has absorbed ’ earth ’ or has corroded or touched metal and somehow become heated." That he realized the difference between mechanical suspension and solution is evident from (De Ortu, p. 50): " A stony juice differs from water which has abraded something from rock, either because it has more of that which deposits, or because heat, by cooking water of that kind, has thickened it, or because there is something in it which has powerful astringent properties." Much of the author’s notion of juices has already been given in the quotations regarding various minerals, but his most general statement on the subject is as follows: (De Ortu, p. 9): " Juices, however, are distinguished from water by their density (crassitudo), and are generated in various ways either when dry things are soaked with moisture and the mixture is heated, in which way by far the greatest part of juices arise, not only inside the earth, but outside it: or’when water running over the earth is made rather dense, in which way, for the most part the juice becomes salty and bitter; or when the moisture stands upon metal, especially copper, and corrodes it, and in this way is produced the juice from which chrysocolla originates. Similarly, when the moisture corrodes friable cupriferous pyrites an acrid juice is made from which is produced vitriol and sometimes alum; or, finally, juices are pressed out by the very force of the heat from the earth. If the force is great the juice flows like pitch from burning pine .... in this way we know a kind of bitumen is made in the earth. In the same way different kinds of moisture are generated in living bodies, so also the earth produces waters differing in quality, and in the same way juices." CONCLUSION. If we strip his theory of the necessary influence of the state of knowledge of his time, and of his own deep classical learning, we find two propositions original with Agricola, which still to-day are fundamentals: (i) That ore channels were of origin subsequent to their containing rocks: (2) That ores were deposited from solutions circulating in these openings. A scientist’s work must be judged by the advancement he gave to his science, and with this gauge one can say unhesitatingly that the theory which we have set out above represents a much greater step from what had gone before than that of almost any single observer since. Moreover, apart from any tangible proposition laid down, the deduction of these views from actual observation instead of from fruitless speculation was a contribution to the very foundation of natural science. Agricola was wrong in attributing the creation of ore channels to erosion alone, and it was not until Von Oppel (Anleiiung zur Markscheidekunst, Dresden, 1749 and other essays), two centuries after Agricola, that the positive proposition that ore channels were due to fissuring was brought forward. Von Oppel, however, in neglecting channels due to erosion (and in this term we include solution) was not altogether sound. Nor was it until late in the 18th century that the filling of ore channels by deposition from solutions was generally accepted. In the meantime, Agricola’s successors in the study of ore deposits exhibited positive retrogression from the true fundamentals advocated by him. Gesner, Utman, Meier, Lohneys, Barba, Rössler, Becher, Stahl, Henckel, and Zimmerman, all fail to grasp the double essentials. Other writers of this period often enough merely quote Agricola, some not even acknowledging the source, as, for instance, Pryce (Mineralogia Cornubiensis, London, 1778) and Williams (Natural History of the Mineral Kingdom, London, 1789). After Von Oppel, the two fundamental principles mentioned were generally accepted, but then arose the complicated and acrimonious discussion of the origin of solutions, and nothing in Agricola’s view was so absurd as Werner’s contention (Neue Theorie von der Entstehung der Gänge, Freiberg, 1791) of the universal chemical deluge which penetrated fissures open at the surface. While it is not the purpose of these notes to pursue the history of these subjects subsequent to the author’s time, it is due to him and to the current beliefs as to the history of the theory of ore deposits, to call the attention of students to the perverse representation of Agricola’s views by Werner (op. cit.) upon which most writers have apparently relied. Why this author should be (as, for instance, by Posepny, Amer. Inst. Mining Engineers, 1901) so generally considered the father of our modern theory, can only be explained by a general lack of knowledge of the work of previous writers on ore deposition. Not one of the propositions original with Werner still holds good, while his rejection of the origin of solutions within the earth itself halted the march of advance in thought on these subjects for half a century. It is our hope to discuss exhaustively at some future time the development of the history of this, one of the most far-reaching of geologic hypotheses.

2. The Latin vena, "vein," is also used by the author for ore; hence this descriptive warning as to its intended double use.
3. The endeavour to discover the origin of the compass with the Chinese, Arabs, or other Orientals having now generally ceased, together with the idea that the knowledge of the lodestone involved any acquaintance with the compass, it is permissible to take a rational view of the subject. The lodestone was well known even before Plato and Aristotle, and is described by Theophrastus (see Note 10, p. 115.) The first authentic and specific mention of the compass appears to be by Alexander Neckam (an Englishman who died in 1217), in his works De Utensilibus and De Naturis Rerum. The first tangible description of the instrument was in a letter to Petrus Peregrinus de Maricourt, written in 1269, a translation of which was published by Sir Sylvanus Thompson (London, 1902). His circle was divided into four quadrants and these quarters divided into 90 degrees each. The first mention of a compass in connection with mines so far as we know is in the Nützlich Bergbüchlin, a review of which will be found in Appendix B. This book, which dates from 1500, gives a compass much like the one described above by Agricola. It is divided in like manner into two halves of 12 divisions each. The four cardinal points being marked Mitternacht, Morgen, Mittag, and Abend. Thus the directions read were referred to as ii. after midnight, etc. According to Joseph Carne (Trans. Roy. Geol. Socy. of Cornwall, Vol. II, 1814), the Cornish miners formerly referred to North-South veins as 12 o’clock veins; South-East North-West veins as 9 o’clock veins, etc.
4. Crudariis. Pliny (xxxiii., 31). says:— "Argenti vena in summo reperta crudaria appellatur," "Silver veins discovered at the surface are called crudaria." The German translator of Agricola uses the term sylber gang—silver vein, obviously misunderstanding the author’s meaning.
5. It might be considered that the term "outcrop" could be used for "head," but it will be noticed that a vena dilatata would thus be stated to have no outcrop.
6. It is possible that "veinlets" would be preferred by purists, but the word "stringer " has become fixed in the nomenclature of miners and we have adopted it. The old English term was "stringe," and appears in Edward Manlove's "Rhymed Chronicle," London, 1653; Pryce's, Mineralogia Cornubiensis, London, 1778, pp. 103 and 329; Mawe's "Mineralogy of Devonshire," London, 1802, p. 210, etc., etc.
7. Subdialis. "In the open air." The Glossary gives the meaning as Ein tag klufft oder tag gehenge—a surface stringer.
8. The following from Chapter iv of the Nillzlich Bergbuchlin (see Appendix B) may indicate the source of the theory which Agricola here discards: " As to those veins which are most profitable to work, it must be remarked that the most suitable location for the vein is on the slope of the mountain facing south, so its strike is from vn or vi east to vi or vn west. According to the above-mentioned directions, the outcrop of the whole vein should face north, its gesteins ausgang toward the east, its hangingwall toward the south, and its footwall toward the north, for in such mountains and veins the influence of the planets is conveniently received to prepare the matter out of which the silver is to be made or formed. . . . The other strikes of veins from between east and south to the region between west and north are esteemed more or less valuable, according to whether they are nearer or further away from the above-mentioned strikes, but with the same hanging- wall, footwall, and outcrops. But the veins having their strike from north to south, their hangingwall toward the west, their footwall and their outcrops toward the east, are better to work than veins which extend from south to north, whose hangingwalls are toward the east, and footwalls and outcrops toward the west. Although the latter veins sometimes yield solid and good silver ore, still it is not sure and certain, because the whole mineral force is completely scattered and dispersed through the outcrop, etc."
9. The names in the Latin are given as Donum Divinum " God’s Gift," and Coelestis Exercilus " Heavenly Host." The names given in the text are from the German Translation. The former of these mines was located in the valley of Joachim, where Agricola spent many years as the town physician at Joachimsthal. It is of further interest, as Agricola obtained an income from it as a shareholder. He gives the history of the mine (De Veteribus et Novis Metallis, Book I.), as follows: "The mines at Abertham were discovered, partly by chance, partly by science. In the eleventh year of Charles V. (1530), on the 18th of February, a poor miner, but one skilled in the art of mining, dwelt in the middle of the forest in a solitary hut, and there tended the cattle of his employer. While digging a little trench in which to store milk, he opened a vein. At once he washed some in a bowl and saw particles of the purest silver settled at the bottom. Overcome with joy he informed his employer, and went to the Bergmeister and petitioned that official to give him a head mining lease, which in the language of our people he called Gottsgaab. Then he proceeded to dig the vein, and found more fragments of silver, and the miners were inspired with great hopes as to the richness of the vein. Although such hopes were not frustrated, still a whole year was spent before they received any profits from the mine; whereby many became discouraged and did not persevere in paying expenses, but sold their shares in the mine; and for this reason, when at last an abundance of silver was being drawn out, a great change had taken place in the ownership of the mine; nay, even the first finder of the vein was not in possession of any share in it, and had spent nearly all the money which he had obtained from the selling of his shares. Then this mine yielded such a quantity of pure silver as no other mine that has existed within our own or our fathers’memories, with the exception of the St. George at Schneeberg. We, as a share- holder, through the goodness of God, have enjoyed the proceeds of this ’ God’s Gift ’ since the very time when the mine began first to bestow such riches." Later on in the same book he gives the following further information with regard to these mines: " Now if all the individual mines which have proved fruitful in our own times are weighed in the balance, the one at Annaberg, which is known as the Himmelsch hoz, surpasses all others. For the value of the silver which has been dug out has been estimated at 420,000 Rhenish gulden. Next to this comes the lead mine in Joachimsthal, whose name is the Sternen, from which as much silver has been dug as would be equivalent to 350,000 Rhenish gulden; from the Gottsgaab at Abertham, explained before, the equivalent of 300,000. But far before all others within our fathers’memory stands the St. George of Schneeberg, whose silver has been estimated as being equal to two million Rhenish gulden." A Rhenish gulden was about 6.9 shillings, or, say, $1.66. However, the ratio value of silver to gold at this period was about 11.5 to one, or in other words an ounce of silver was worth about a gulden, so that, for purposes of rough calculation, one might say that the silver product mentioned in gulden is practically of the same number of ounces of silver. Moreover, it must be remembered that the purchasing power of money was vastly greater then.
10. The following passage occurs in the Nutzlich Bergbuchlin (Chap. V.), which is interesting on account of the great similarity to Agricola’s quotation: " The best position of the stream is when it has a cliff beside it on the north and level ground on the south, but its current should be from east to west that is the most suitable. The next best after this is from west to east, with the same position of the rocks as already stated. The third in order is when the stream flows from north to south with rocks toward the east, but the worst flow of water for the preparation of gold is from south to north if a rock or hill rises toward the west." Calbus was probably the author of this booklet.
11. Albertus Magnus.

END OF BOOK III.

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