[67.] Or myrtles.) This is prepared by bruising and pressing the tender leaves of the black myrtle, and mixing their juice with an equal quantity of the oil of unripe olives, then boiling them together, and taking off whatever swims upon the top. Some thicken the oil first with pomegranate bark, cypress, &c. Dioscorid. lib. i. cap. 49.
[68.] Of roses.) This is made by boiling the juncus odoratus with water and oil, and after straining, fresh roses are infused in the oil: they are stirred frequently with the hands rubbed with honey, and squeezed. When they have stood for a night, they are pressed out. A second and third kind of rose oil is prepared, by infusing the same roses in fresh quantities of oil. Dioscorid. lib. i. cap. 54.
[69.] Bitter oil.) This has probably been prepared from the wild olive; for Pliny says, such is thin, and much more bitter than what is made from the olive. Lib. xv. cap. 7.
[70.] Made of far.) Far is a species of wheat.—Columella reckons four kinds of it. Pliny says it is the hardest of all, and firmest against winter. It was called also semen adoreum. It was the first grain the Romans used. Pliny, lib. xvii. cap. 8, et Columella, lib. ii. cap. 6.
[71.] Cyprine oil was made from the tree called cyprus in Egypt, according to Pliny—And in his time some conjectured it to be the same with the ligustrum of Italy. Plin. Nat. Hist. lib. xii. c. 24.
[72.] Oil of iris.) The oil is first inspissated by boiling it with water, and the involucrum of the fruit of the palm tree (called by Dioscorides, spatha). When this is done, an equal quantity of bruised iris is infused with this inspissated and aromatized oil, which stands for two days and two nights, and then is strongly expressed. A more fragrant kind is prepared by inspissating the oil with balsam-wood and calamus. After expression, a fresh quantity of iris may be added, if it be desired stronger. Dioscorid. lib. i. cap. 67.
[73.] Nitre.) So much has been said by modern authors concerning the nitre of the ancients, that it would be impertinent to give a particular account of it here. The greatest plenty was produced in Egypt, in the lands which the Nile had overflowed. Most naturalists believe it to have been a native alkaline salt. Pliny says, it was adulterated in Egypt by lime, but that trick was easily discovered by putting it in water, when the true nitre would dissolve, and the lime not. Plin. lib. xxxi. cap. 10. where a long account of it may be seen.