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southerly regions of Europe as Ultima Thule—the ice-bound northern
limit of the world. Speculation has identified the island as Iceland, but
Iceland was unpopulated until early medieval times. Many historians now
believe that Pytheas was in Norwegian waters (though some have identi-
fied Thule with the Estonian island of Saaremaa, in the Baltic). The nights
at this latitude, he noted, were of only two or three hours' duration. He
traveled still further north, where the sea was frozen. His description is of
pancake ice at the edge of drift ice, amid sea, slush, and fog, so common in
polar regions. Strabo, a Greek geographer writing some 300 years later,
noted that Pytheas spoke ''about Thule and about those regions in which
there was no longer either land properly so-called, or sea, or air, but a kind
of substance concreted from all these elements, resembling a sea-lungs—
a thing in which, he says, the earth, the sea, and all the elements are held in
suspension; and this is a sort of bond to hold all together, which you can
neither walk nor sail upon.''
11
The journey home was probably via the English Channel. Pytheas was a
true explorer. We can sense his amazement at what he found at the end of
the world. He must have felt very far from home amid that pancake ice. He
was knowledgeable about maritime navigation; he knew about Polaris and
was familiar with the gnomon, so he could determine latitude by day or
night, weather permitting. (At one point in his life he made an estimate of
the latitude of Massilia, with an error of only 5 minutes of arc.)
Clearly, there was more to Pytheas's voyage than trade considerations. I
get the impression that he was a skilled negotiator, not just because of the
trade goods he brought home but also because there is no mention of any
hostility from the Celtic and Germanic tribes he encountered. He wrote an
influential account of his expedition in a book entitled
On the Ocean
, of
which only fragments remain. However, many of the classical writers,
including Strabo and Pliny the Elder, must have had access to his work
because it is through them that we know about Pytheas of Massilia.
Letting Go of the Shore
Through the centuries, knowledge of navigation accumulated in fits and
starts. Knowledge of lead lines was gained and then lost in some parts of
the world. They were reinvented in Europe in the thirteenth century for
11. Strabo,
Geographica
, 2.4.1. Translation available online at
http://penelope.uchicago
