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.
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.
