Page:De re metallica (1912).djvu/85



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 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:

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.

. 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. 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 ; 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.