[30] Thus, or tus—"incense."
[31] One centumpondium, Roman, equals about 70.6 lbs. avoirdupois; one centner, old German, equals about 114.2 lbs. avoirdupois. Therefore, if German weights are meant, the maximum charge would be about 5.7 short tons; if Roman weights, about 3.5 short tons.
[Pg 473][32] See description, p. [269].
[33] Stannum, as a term for lead-silver alloys, is a term which Agricola (De Natura Fossilium, pp. 341-3) adopted from his views of Pliny. In the Interpretatio and the Glossary he gives the German equivalent as werk, which would sufficiently identify his meaning were it not obvious from the context. There can be little doubt that Pliny uses the term for lead alloys, but it had come into general use for tin before Agricola's time. The Roman term was plumbum candidum, and as a result of Agricola's insistence on using it and stannum in what he conceived was their original sense, he managed to give considerable confusion to mineralogic literature for a century or two. The passages from Pliny, upon which he bases his use, are (XXXIV, 47): "The metal which flows liquid at the first melting in the furnace is called stannum, the second melting is silver," etc. (XXXIV, 48): "When copper vessels are coated with stannum they produce a less disagreeable flavour, and it prevents verdigris. It is also remarkable that the weight is not increased.... At the present day a counterfeit stannum is made by adding one-third of white copper to tin. It is also made in another way, by mixing together equal parts of tin and lead; this last is called by some argentarium.... There is also a composition called tertiarium, a mixture of two parts of lead and one of tin. Its price is twenty denarii per pound, and it is used for soldering pipes. Persons still more dishonest mix together equal parts of tertiarium and tin, and calling the compound argentarium, when it is melted coat articles with it." Although this last passage probably indicates that stannum was a tin compound, yet it is not inconsistent with the view that the genuine stannum was silver-lead, and that the counterfeits were made as stated by Pliny. At what period the term stannum was adopted for tin is uncertain. As shown by Beckmann (Hist. of Inventions II, p. 225), it is used as early as the 6th century in occasions where tin was undoubtedly meant. We may point out that this term appears continuously in the official documents relating to Cornish tin mining, beginning with the report of William de Wrotham in 1198.
[Pg 475][34] The Latin term for litharge is spuma argenti, spume of silver.
[35] Pliny, XXXIII, 35. This quotation is given in full in the [footnote p. 466]. Agricola illustrates these "tubes" of litharge on p. [481].
[36] Assuming Roman weights, three unciae and three drachmae per centumpondium would be about 82 ozs., and the second case would equal about 85 ozs. per short ton.
[37] Agricola uses throughout De Re Metallica the term molybdaena for this substance. [Pg 476]It is obvious from the context that he means saturated furnace bottoms—the herdpley of the old German metallurgists—and, in fact, he himself gives this equivalent in the Interpretatio, and describes it in great detail in De Natura Fossilium (p. 353). The derivatives coined one time and another from the Greek molybdos for lead, and their applications, have resulted in a stream of wasted ink, to which we also must contribute. Agricola chose the word molybdaena in the sense here used from his interpretation of Pliny. The statements in Pliny are a hopeless confusion of molybdaena and galena. He says (XXXIII, 35): "There are three varieties of it (litharge)—the best-known is chrysitis; the second best is called argyritis; and a third kind is called molybditis.... Molybditis is the result of the smelting of lead.... Some people make two kinds of litharge, which they call scirerytis and peumene; and a third variety being molybdaena, will be mentioned with lead." (XXXIV, 53): "Molybdaena, which in another place I have called galena, is an ore of mixed silver [Pg 477]and lead. It is considered better in quality the nearer it approaches to a golden colour and the less lead there is in it; it is also friable and moderately heavy. When it is boiled with oil it becomes liver-coloured, adheres to the gold and silver furnaces, and in this state it is called metallica." From these two passages it would seem that molybdaena, a variety of litharge, might quite well be hearth-lead. Further (in XXXIV, 47), he says: "The metal which flows liquid at the first melting in the furnace is called stannum, at the second melting is silver, that which remains in the furnace is galena." If we still maintain that molybdaena is hearth-lead, and galena is its equivalent, then this passage becomes clear enough, the second melting being cupellation. The difficulty with Pliny, however, arises from the passage (XXXIII, 31), where, speaking of silver ore, he says: "It is impossible to melt it except with lead ore, called galena, which is generally found next to silver veins." Agricola (Bermannus, p. 427, &c.), devotes a great deal of inconclusive discussion to an attempt to reconcile this conflict of Pliny, and also that of Dioscorides. The probable explanation of this conflict arises in the resemblance of cupellation furnace bottoms to lead carbonates, and the native molybdaena of Dioscorides; and some of those referred to by Pliny may be this sort of lead ores. In fact, in one or two places in [Book IX], Agricola appears to use the term in this sense himself. After Agricola's time the term molybdaenum was applied to substances resembling lead, such as graphite, and what we now know as molybdenite (MoS2). Some time in the latter part of the 18th century, an element being separated from the latter, it was dubbed molybdenum, and confusion was five times confounded.
[Pg 480][38] Agricola here refers to the German word used in this connection, i.e., hundt, a dog.
[Pg 483][39] If Agricola means the German centner, this charge would be from about 4.6 to 5.7 short tons. If he is using Roman weights, it would be from about 3 to 3.7 short tons.