agnete_, many points came up for discussion, requiring critical
consideration, and the examination of the writings of contemporary or
earlier authorities. Discrepancies between the texts of the three known
editions--the London folio of 1600, and the two Stettin quartos of 1628 and
1633 respectively--demanded investigation. Passages relating to astrology,
to pharmacy, to alchemy, to geography, and to navigation, required to be
referred to persons acquainted with the early literature of those branches.
Phrases of non-classical Latin, presenting some obscurity, needed
explanation by scholars of mediaeval writings. Descriptions of magnetical
experiments needed to be interpreted by persons whose knowledge of
magnetism enabled them to infer the correct meaning to be assigned to the
words in the text. In this wise a large amount of miscellaneous criticism
has been brought to bear, and forms the basis for the following notes. To
make them available to all students of Gilbert, the references are given to
page and line both of the Latin folio of 1600 and of the English edition of
1900. S. P. T.

[1] _THE GLOSSARY:_

Gilbert's glossary is practically an apology for the introduction into the
Latin language of certain new words, such as the nouns _terrella_,
_versorium_, and _verticitas_, and the adjectival noun _magneticum_, which
either did not exist in classical Latin or had not the technical meaning
which he now assigns to them. His _terrella_, or [Greek: mikroge], as he
explains in detail on p. 13, is a little magnetic model of the earth, but
in the glossary he simply defines it as _magnes globosus_. Neither
_terrella_ nor _versorium_ appears in any Latin dictionary. No older writer
had used either word, though Peter Peregrinus (_De Magnete_, Augsburg,
1558) had described experiments with globular loadstones, and pivotted
magnetic needles suitable for use in a compass had been known for nearly
three centuries. Yet the pivotted needle was not denominated _versorium_.
Blondo (_De Ventis_, Venice, 1546) does not use the term. Norman (_The Newe
Attractiue_, London, 1581) speaks of the "needle or compasse," and of the
"wyre." Barlowe (_The Navigators Supply_, London, 1597) speaks of {2} the
"flie," or the "wier." The term _versorium_ (literally, the _turn-about_)
is Gilbert's own invention. It was at once adopted into the science, and
appears in the treatises of Cabeus, _Philosophia Magnetica_ (Ferrara,
1629), and of Kircher, _Magne