2. Epistola de Secretis Operibus Artis et Naturæ et de Nullitate Magiæ.
3. De Mirabili Potestate Artis et Naturæ.
[26] This tract and the next, which is of considerable length, will be found in Mangetus’s Bibliotheca Chemica Curiosa, i. 613.
A number of these were collected together, and published at Frankfort in 1603, under the title of “Rogeri Baconis Angli de Arte Chemiæ Scripta,” in a small duodecimo volume. The Opus Majus was published in London in 1733, by Dr. Jebb, in a folio volume. Several of his tracts still continue in manuscript in the Harleian and Bodleian libraries at Oxford. He considered the metals as compound of mercury and sulphur. Gmelin affirms that he was aware of the peculiar nature of manganese, and that he was acquainted with bismuth; but after perusing the whole of the Speculum Alchymiæ, the third chapter of which he quotes as containing the facts on which he founds his opinion, I cannot find any certain allusion either to manganese or bismuth. The term _magnesia_ indeed occurs, but nothing is said respecting its nature: and long after the time of Paracelsus, bismuth (_bisematum_) was considered as an impure kind of _lead_. That he was acquainted with the composition and properties of _gunpowder_ admits of no doubt. In the sixth chapter of his epistle De Secretis Operibus Artis et Naturæ et de Nullitate Magiæ, the following passage occurs:
“For sounds like thunder, and coruscations like lightning, may be made in the air, and they may be rendered even more horrible than those of nature herself. A small quantity of matter, properly manufactured, not larger than the human thumb, may be made to produce a horrible noise and coruscation. And this may be done many ways, by which a city or an army may be destroyed, as was the case when Gideon and his men broke their pitchers and exhibited their lamps, fire issuing out of them with inestimable noise, destroyed an infinite number of the army of the Midianites.” And in the eleventh chapter of the same epistle occurs the following passage: “Mix together saltpetre, luru vopo vir con utriet, and sulphur, and you will make thunder and lightning, if you know the method of mixing them.” Here all the ingredients of gunpowder are mentioned except charcoal, which is doubtless concealed under the barbarous terms _luru vopo vir con utriet_.