third series
of experimental magnetical discoveries extends throughout Book III.

[86] PAGE 31, LINE 30. Page 31, line 25. _verticem._--The context and the
heading of the Chapter appear to require _verticitatem_. All editions,
however, read _verticem_.

[87] PAGE 32, LINE 12. Page 32, line 9. _Gartias ab horto._--The passage
from Gartias ab Horto runs as follows in the Italian edition of 1616,
_Dell' Historia dei Semplici Aromati._... di Don Garzia dall' Horto, Medico
Portughese, ... Venezia MDCXVI., p. 208.

"Ne meno e questa pietra velenosa, si come molti hanno tenuto; imperoche le
genti di queste bande dicono che la Calamita presa per bocca, pero in poca
{28} quantita, conserva la gioventu. La onde si racconta, che il Re di
Zeilan il vecchio' s'haveva fatto fare tutti i vasi, dove si cocevano le
vivade per lui, di Calamita. Et questo lo disse a me colui proprio, che fu
a questo officio destinato."

[88] PAGE 32, LINE 29. Page 32, line 29. _Plutarchus & C. Ptolemaeus._--The
garlick myth has already been referred to in the note to p. 1. The
originals are Plutarch, _Quaestiones Platonicae_, lib. vii., cap. 7, s. 1;
C. Ptolemaeus, _Opus Quadripartitum,_ bk. i., cap. 3. The English
translation of the latter, by Whalley (London, 1701), p. 10, runs: "For if
the _Loadstone_ be _Rubbed_ with _Garlick_, the _Iron will not be drawn by
it_."

[89] PAGE 32, LINE 32. Page 32, line 33. _Medici nonnulli._--This is
apparently a reference to the followers of Rhazes and Paracelsus. The
argument of Gilbert as to the inefficacy of powdered loadstones is
reproduced more fully by William Barlowe in his _Magneticall
Aduertisements_ (1616, p. 7), as follows:

"It is the goodnesse of the _Loadstone_ ioyned with a fit forme that will
shew great force. For as a very good forme with base substance can doe but
very litle, so the substance of the _Loadstone_ bee it neuer so excellent,
except it haue some conuenient forme, is not auaileable. For example, an
excellent _loadstone_ of a pound waight and of a good fashion, being vsed
artificially, may take vp foure pounds of Iron; beate it into small pouder,
and it shall bee of no force to take vp one ounce of Iron; yea I am very
well assured that halfe an ounce of a Loadstone of good fashion, and of
like vertue will take vp more then that pound will doe being beaten into
powder. Whence (to adde this by the way) it appeareth manifestly, that it
is a great error of those Physitions and Surgeons, w