Sulfur is a vein of earth, having in its composition much airiness and fieriness, and is, according to Isidore, called sulfur for the reason that it burns earth. That it is said to be of fire since its power is fiery is seen from boiling water. For a channel of water, making its way through veins of sulfur, brings along with it heat and warmth from the fiery power of the sulfur itself, and also its taste, powers, and odor. Therefore hot springs often bubble up from the interior of the earth, and bring the qualities of the vein of sulfur with them, for nothing burns as quickly as sulfur. It originates in the Aeolian islands between Sicily and Italy, islands which they say burn, and is also found excavated in other places, as Isidore says.

Huius quatuor sunt genera. Unus viuum quod cum foditur, translucet atque viret, quo solo inter omnia genera medici ununtur, ut dicit Isidorus. Alterum quoque appellant glebam, quod tantum familiare usibus est fullonum.  Tertium liquor est, cuius usus est ad lanas utilis suffundendas, quoniam praestat mollitiem et candorem.  Quartum valet ad licinia lucernarum conficienda, ut dicit Isidorus.

Et subdit ibidem Sulphuris tanta est vis, ut morbos comitiales deprehendat nitore suo, cuius flamma, si directe ad vultum hominis repercutiat durum et horribilem pallorem in oculis aspicientium generat ad similitudinem defunctorum, ut dicit Isidorus lib 16 cap 1. Secumdum Auicennam uero et Platonem sulphur calidum est et siccum in quarto gradu.

Sulphur autem aliud est viuum scil. quale est, quando de terra est eductum. Aliud est mortuum vel extioctum, scilicet quod solet fieri artisiciose, scilicet quod in calamos funditur vel in alia vasa. Eligendum autem est pro medicina uiuum, colore et resplendens, perlucidum, et fine lapide album vel veride, quod missum in ignem, colorem facit vitidem atque pinguem.  Virtutem habet dissoluendi, consumendi, attrahendi, subtilandi, attenuandi, reformandi vel recuperandi. Et ideo tussim prohibet, epilepticos iuuat, scabie purgat, venenis obuiat, lethargicos excitat, arteticos, podagricos, paralyticos iuuat, si modo debito medicinaliter ipsius remedio quis utatur, ut dicit Auicenna et Dioscor, et Plato et alii autores.