. There are
several earlier references, however, to the use of the directive
properties of loadstone, mainly for use in navigation, but these
earliest texts have a long history of erroneous interpretation which is
only recently being cleared away. We know now that the famous passages
in the _De naturis rerum_ and _De utensilibus_ of Alexander Neckham[43]
(_ca._ 1187) and a text by Hugues de Berze[44] (after _ca._ 1204) refer
to nothing more than a floating magnet without pivot or scale, but using
a pointer at right angles to the magnet, so that it pointed to the east,
rather than the north or south. A similar method is described (_ca._
1200) in a poem by Guyot de Provins, and in a history of Jerusalem by
Jacques de Vitry (1215).[45] It is of the greatest interest that, once
more, all the evidence seems to be concentrated in France (Neckham was
teaching in Paris) though at an earlier period than that for the
protoclocks.

The date might suggest the time of the first great wave of transmissal
of learning from Islam, but it is clear that in this instance, peculiar
for that reason, that Islam learned of the magnetic compass only after
it was already known in the West. In the earliest Persian record, some
anecdotes compiled by al-'Awfi[=i] _ca._ 1230,[46] the instrument used
by the captain during a storm at sea has the form of a piece of hollow
iron, shaped like a fish and made to float on the water after
magnetization by rubbing with a loadstone; the fishlike form is very
significant, for this is distinctly Chinese practice. In a second Muslim
reference, that of Bailak al-Qab[=a]jaq[=i] (_ca._ 1282), the ordinary
wet-compass is termed "al-konbas," another indication that it was
foreign to that language and culture.[47]

Chronological Chart

------------------------------------------------------------------------

CHINA

4th C., B.C. Power gearing

CLASSICAL EUROPE

3rd C., B.C. Archimedes planetarium
2nd C., B.C. Hipparchus Stereographic Projection
1st C., B.C. Vitruvius hodometer and water clocks
65, B.C. (_ca._) Antikythera machine
1st C., A.D. Hero hodometer and water clocks
2nd C., A.D. Salzburg and Vosges anaphoric clocks

CHINA

2nd C., A.D. Chang Heng animated globe hodometer
Continuing tradition of animated astronomical models
725 Invention of Chinese escapement by I-Hsing and Liang Ling-tsan

ISLAM

807 Harun-al-Rashid
850 (_ca._) Earliest extant astrolabes