ows a nice
appreciation of words and their use, and a knowledge of style. One finds
occasionally direct quotations from, and overt references to, the classic
authors, as in the references to Plato and Aristotle on page 1, and in the
passage from the Georgics of Vergil on p. 21. But here and there one finds
other traces of unmistakable scholarship, as in the reference to goat's
wool on p. 35, or in the use, on p. 210, of the word _perplacet_, which
occurs in the letter of Cicero _ad Atticum_, or in that of _commonstrabit_,
occurring on p. 203, and found only in Cicero, Terence and Plautus; whilst
the phrase on p. 3, in which Gilbert rallies the smatterers on having lost
both their oil and their pains, has a delightfully classical echo. {3} The
term _orbis virtutis_, defined by Gilbert in the glossary, and illustrated
by the cuts on pages 76, 77, and 96, might be effectively translated by
_sphere of influence_, or _orbit within which there is sensible
attraction_. It has been preferred, however, to translate it literally as
the _orbe of virtue_, or _orbe of magnetick virtue_. This choice has been
determined by the desire to adopt such an English phrase as Gilbert would
himself have used had he been writing English. T. Hood, writing in 1592 in
his book _The Vse of both the Globes_, in using the word _orbe_, says that
the word _globe_ signifies a solid body, while a _sphere_ is hollow, like
two "dishes joyned by the brimme"; "The Latines properly call _Orbis_ an
Orbe"; "Moreouer the word _Sphaera_ signifieth that instrument made of
brasen hoopes (wee call it commonly a ringed Sphere) wherewith the
Astronomers deliuer unto the nouices of that Science the vnderstanding of
things which they imagine in the heauen." Further, Dr. Marke Ridley in his
_Treatise of Magneticall Bodies and Motions_ (1613), has a chapter (XIIII)
"Of the distance and Orbe of the Magnets vertue," throughout which the term
Orbe is retained. Sir Thomas Browne also writes of "the orb of their
activities."

The word _Coitio_, used by Gilbert for the mutual force between magnet and
iron, has been retained in its English form, _coition_. Gilbert evidently
adopted this term after much thought. The Newtonian conception of action
and reaction being necessarily equal had not dawned upon the mediaeval
philosophers. The term _attraction_ had been used in a limited sense to
connote an action in which a force was conceived of as being exerted on one
side only. Diogenes