BOOK III.

REVIOUSLY I have given much informationconcerning the miners, also I have discussed thechoice of localities for mining, for washing sands,and for evaporating waters; further, I describedthe method of searching for veins. With suchmatters I was occupied in the second book; now Icome to the third book, which is about veins andstringers, and the seams in the rocks 1 . Theterm "vein” is sometimes used to indicate candlesin the earth, but very often elsewhere by this name I have described thatwhich may be put in vessels 2 ; I now attach a second significance tothese words, for by them I mean to designate any mineral substances whichthe earth keeps hidden within her own deep receptacles.

'■‘dtl.-.

1 Modern nomenclature in the description of ore-deposits is so impregnated with modernviews of their origin, that we have considered it desirable in many instances to adopt theLatin terms used by the author, for we.believe this method will allow the reader greaterfreedom of judgment as to the author’s views. The Latin names retained are usuallyexpressive 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 replacementor a stockwerk. The candles, as will appear from the following footnote, were ore channels.“ The seams of the rocks ” (commissurae saxorum) are very puzzling. The author states, asappears in the following note, that they are of two kinds,—-contemporaneous with the formationof the rocks, and also of the nature of veinlets. However, as to their supposed relation tothe strike of veins, we can offer no explanation. There are passages in this chapter whereif the word “ore-shoot” were introduced for “seams in the rocks” the text would be in-telligible. That is, it is possible to conceive the view that the determination of whether aneast-west vein ran east or ran west was dependent on the dip of the ore-shoot along thestrike. This view, however, is utterly impossible to reconcile with the description andillustration of commissurae saxorum given on page 54, where they are defined as the fineststringers. 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 tothe 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(i °t the whole vein. The other ausgehen is contrary to or toward the strike (streichen) oftt 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 gesteins ausgehen to the east, and“ vice-versa.”

Agricola’s classification of ore-deposits, after the general distinction between alluvialand in situ deposits, is based entirely upon form, as will be seen in the quotation below relatingto the origin of candles. 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, andJater in De Re Metallica he describes the Mannsfeld copper schists, as all being venae dilatatae.1 his nomenclature and classification is not original with Agricola. Pliny (xxxm, 21) usesthe term vena with no explanations, and while Agricola coined the Latin terms for variouskinds of veins, they are his transliteration of German terms already in use. The Nutzlicheergbuchlin gives this same classification.

Historical Note on the Theory of Ore Deposits. Prior to Agricola there werehree schools of explanation of the phenomena of ore deposits, the orthodox followers of theenesis, the Greek Philosophers, and the Alchemists. The geology of the Genesis—thecontemporaneous formation of everything—needs no comment other than that for anyone toave proposed an alternative to the dogma of the orthodox during the Middle Ages, required

®The Latin vena, " vein,” is also used by the author for ore ; hence this descriptivearmng as to its intended double use.