Georgius Agricola

“ 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. ”

“ 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? ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 ”

“ 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 ”

“ 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. ”

“ 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 ”