3 Which she had gathered in a shady glade 4 Of the Riphaean hills, to her revealed
Riphaean hills > {The mountains in Scythia, i.e. northern Europe and
Asiatic Russia}
5 By errant sprites, but from all men concealed:
errant > wandering
6 The same she tempered with fine mercury,
tempered > blended mercury > (Formerly numbered among the five elementary "principles" of which all matter was said to be composed; also called "spirit". According to Paracelsus, mercury is one of three basic components of man. Mercury was also a symbol of sprightliness, volatility, and inconstancy)
7 And virgin wax, that never yet was sealed,
sealed > [used for sealing]
8 And mingled them with perfect vermilion,
vermilion > {Cinnabar, red crystalline mercuric sulphide, used in the manufacture of red sealing-wax: it is the ore from which most of the world's mercury is derived}