stone. And this turning of the cusp (that is, of the end
touched by that pole) as well as of the cross-end, at a greater distance,
takes place with an iron globe interposed, which would not happen at all if
* the space were empty, because the magnetick virtue is passed on and
continued through magnetick bodies.

[Illustration]

A is a terrella, B an iron globe; between the two bodies is F, a versorium
whose point has been excited by the pole C. In the other figure A is a
terrella, C its pole, B an iron globe; where the versorium tends towards C,
the pole of the terrella, through the iron globe. So a versorium placed
between a terrella and an iron globe vibrates more forcibly towards the
pole of the terrella; because the loadstone sends an instantaneous
verticity into the opposite globe. There is the same efficiency in the
earth, produced from the same cause. For if a revolvable needle is shut up
in a rather thick gold box (this metal indeed excels all others in density)
or a glass or stone box, nevertheless that magnetick needle has its forces
connected and united with the influences of the earth, and the iron will
turn freely and readily (unhindered by its prison) to its desired points,
North and South. * It even does this when shut up in iron caverns, if they
are sufficiently spacious. Whatever bodies are produced among us, or are
artificially forged from things which are produced, consist of matter of
the terrestrial globe; nor do those bodies hinder the prime forces of
nature which are derived from their primary form, nor can they resist them
except by contrary forms. But no forms of mixed bodies are inimical to the
primary implanted earth-nature, although some often do not agree[169] with
one another. But in the case of all those substances which have a material
cause for their inclining (as amber, {86} jet, sulphur), their action is
impeded by the interposition of a body (as paper, leaves, glass, or the
like) when that way is impeded and obstructed, so that that which
exhales[170] cannot reach the corpuscle to be allured. Terrestrial and
magnetick coition and motion, when corporeal impediments are interposed, is
demonstrated also by the efficiencies of other chief bodies due to their
primary form. The moon (more than all the stars) agrees with internal parts
of the earth on account of its nearness and similarity in form. The moon
produces the movements of the waters and the tides of the sea; twice it
fills up the