Note 8 — BOOK XII.

This paragraph displays hopeless ignorance. Borax was known to Agricola and greatly used in his time; it certainly was not made from these compounds, but was imported from Central Asia. Sal-ammoniac was also known in his time, and was used like borax as a soldering agent. The reaction given by Agricola would yield free ammonia. The following historical notes on borax and sal-ammoniac may be of service.

Borax.—The uncertainties of the ancient distinctions in salts involve borax deeply. The word Baurach occurs in Geber and the other early Alchemistic writings, but there is nothing to prove that it was modern borax. There cannot be the slightest doubt, however, that the material referred to by Agricola as borax was our borax, because of the characteristic qualities incidentally mentioned in Book VII. That he believed it was an artificial product from nitrum is evident enough from his usual expression "chrysocolla made from nitrum, which the Moors call borax." Agricola, in De Natura Fossilium (p. 206-7), makes the following statements, which could leave no doubt on the subject:—"Native nitrum is found in the earth or on the surface.... It is from this variety that the Venetians make chrysocolla, which I call borax.... The second variety of artificial nitrum is made at the present day from the native nitrum, called by the Arabs tincar, but I call it usually by the Greek name chrysocolla; it is really the Arabic borax.... This nitrum does not decrepitate nor fly out of the fire; however, the native variety swells up from within." The application of the word chrysocolla (chrysos, gold; colla, solder) to soldering materials, and at the same time to the copper mineral, is of Greek origin. If any further proof were needed as to the substance meant by Agricola, it lies in the word tincar. For a long time the borax of Europe was imported from Central Asia, through Constantinople and Venice, under the name of tincal or tincar. When this trade began, we do not know; evidently before Agricola's time. The statement here of making borax from alum and sal-ammoniac is identical with the assertion of Biringuccio (II., 9).

Sal-ammoniac.—The early history of this—ammonium chloride—is also under a cloud. Pliny (XXXI., 39) speaks of a sal-hammoniacum, and Dioscorides (V., 85) uses much the same word. Pliny describes it as from near the temple of Ammon in Egypt. None of the distinctive characteristics of sal-ammoniac are mentioned, and there is every reason to believe it was either common salt or soda. Herodotus, Strabo, and others mention common salt sent from about the same locality. The first authentic mention is in Geber, who calls it sal-ammoniacum, and describes a method of making, and several characteristic reactions. It was known in the Middle Ages under various names, among them sal-aremonicum. Agricola (De Nat. Fos., III., p. 206) notes its characteristic quality of volatilization. "Sal-ammoniac ... in the fire neither crackles nor flies out, but is totally consumed." He also says (p. 208): "Borax is used by goldsmiths to solder gold, likewise silver. The artificers who make iron needles (tacks?) similarly use sal-ammoniac when they cover the heads with tin." The statement from Pliny mentioned in this paragraph is from XXXIII., 29, where he describes the chrysocolla used as gold solder as made from verdigris, nitrum, and urine in the way quoted. It is quite possible that this solder was sal-ammoniac, though not made in quite this manner. Pliny refers in several places (XXXIII., 26, 27, 28, and 29, XXXV., 28, etc.) to chrysocolla, about which he is greatly confused as between gold-solder, the copper mineral, and a green pigment, the latter being of either mineral origin.