[991] “Tubulis.” These cakes were probably made in a tubular form.
[992] “Vena;” meaning the ore probably in its raw state, and mixed with earth. All these distinctions are probably unfounded.
[994] Of “Puteolana.”
[995] The litharge.
[996] The scoria.
[997] Nothing whatever is known as to the identity of these varieties of litharge. Indeed the words themselves are spelt in various ways in the respective MSS.
[998] In B. xxxiv. c. [53], where he identifies it with “galena,” mentioned in Chapter [31] of this Book.
[999] See B. xviii. c. 13, B. xvi. c. 61, and B. xxii. c. 66.
[1000] Sal gem, or common salt.