res.]

The introduction of a silk manufacture at Palermo, by Roger Guiscard in
1148, gave perhaps the earliest impulse to the industry of Italy. Nearly
about the same time the Genoese plundered two Moorish cities of Spain,
from which they derived the same art. In the next age this became a
staple manufacture of the Lombard and Tuscan republics, and the
cultivation of mulberries was enforced by their laws.[609] Woollen
stuffs, though the trade was perhaps less conspicuous than that of
Flanders, and though many of the coarser kinds were imported from
thence, employed a multitude of workmen in Italy, Catalonia, and the
south of France.[610] Among the trading companies into which the
middling ranks were distributed, those concerned in silk and woollens
were most numerous and honourable.[611]

[Sidenote: Invention of the mariner's compass.]

A property of a natural substance, long overlooked even though it
attracted observation by a different peculiarity, has influenced by its
accidental discovery the fortunes of mankind more than all the
deductions of philosophy. It is, perhaps, impossible to ascertain the
epoch when the polarity of the magnet was first known in Europe. The
common opinion, which ascribes its discovery to a citizen of Amalfi in
the fourteenth century, is undoubtedly erroneous. Guiot de Provins, a
French poet, who lived about the year 1200, or, at the latest, under St.
Louis, describes it in the most unequivocal language. James de Vitry, a
bishop in Palestine, before the middle of the thirteenth century, and
Guido Guinizzelli, an Italian poet of the same time, are equally
explicit. The French, as well as Italians, claim the discovery as their
own; but whether it were due to either of these nations, or rather
learned from their intercourse with the Saracens, is not easily to be
ascertained.[612] For some time, perhaps, even this wonderful
improvement in the art of navigation might not be universally adopted by
vessels sailing within the Mediterranean, and accustomed to their old
system of observations. But when it became more established, it
naturally inspired a more fearless spirit of adventure. It was not, as
has been mentioned, till the beginning of the fourteenth century that
the Genoese and other nations around that inland sea steered into the
Atlantic Ocean towards England and Flanders. This intercourse with the
northern countries enlivened their trade with the Levant by the exchange
of productions wh