52 ESSEX WORTHIES.
William Gilbert, a clergyman, who bore the same arms ; presumably,
therefore, a descendant of the same family. The Gilbert family still
exists, scattered chiefly over the county of Norfolk.
It is stated by Hervey that Gilbert expended upon his magnetic
researches no less considerable a sum than £5,000. His experi-
ments with loadstones lasted for many years, and he possessed a
remarkable collection of them. He also had many instruments,
some of which are figured in his book. He himself devised
some forms of instruments for navigation, which are described in a
subsequent work by Thomas Blundeville. His charts, globes,
magnets, instruments and manuscripts he bequeathed at his death to
the possession of the Royal College of Physicians. He received a
pension from Queen Elizabeth, by whom he was much esteemed.
It is said, I know not on what authority, that he was the only man to
whom she left anything in her will. You have also a tradition
amongst you, doubtless derived from reliable sources, that Queen
Elizabeth once visited the Doctor at his house in Colchester.
To estimate the magnitude of his achievements in science it is
requisite briefly to review the state of knowledge with respect to
magnetism and electricity before the appearance of his epoch-
making work.
The property of the loadstone to attract pieces of iron, or other
loadstones, was a fact known to antiquity, and explained as usual by
the ascription of magical or occult powers. Pliny mentions that a
ring of iron hung to a loadstone can attract a second, and the
second a third, until a chain of rings hangs from the stone; an
experiment also described in poetry by Lucretius. Lucretius also was
aware that magnetic forces are not screened off by the interposition
of other metals; for he mentions the attraction of iron toward a
brazen vase within which a magnet was enclosed. Nothing more
appears to have been known about the magnet until about the
eleventh century, when the directive power of the loadstone became
known. This discovery, so important in the history of navigation, is
variously attributed to the Chinese, the Arabians, and to an Italian
named Flavio Goia, who lived at Amalfi, in the thirteenth century.
Gilbert himself states that the mariners' compass was first brought to
Italy from China, in 1260, by the famous traveller, Marco Polo. On
the other hand, in the Icelandic chronicle of Are Frode, which was
written about the end of the eleventh century, there is a distinct
record of the use of the loadstone for directing the seaman.