Porosity and passage

Meaning

In II.1.7 the earth's pores provide the routes through which rising vapour reaches a cooler or receptive condition and becomes mercurial water. The alembic-head comparison explains the movement toward condensation without identifying the earth as a literal manufactured apparatus. Porosity is thus a condition of passage and reception. The earth’s veins and rock hollows are specifically the places where coarser mucilage develops into metallic bodies; the disposition of those wombs accounts for accidental differences in metals said to share one substance.

II.3.29 makes pores the channels by which internally generated sulphurous fumes spread through the members as far as the surface, staining the complexion. The motion here is outward, not merely the admission of an external influence. The author then offers blood’s retreat to the heart as an additional account of pallor. His general ruin claim excepts gold and precious stones, perfected as far as Nature can accomplish; it does not assert that every compound is equally permeable or corruptible.