VIII.] HIS PARALLELS OF LATITUDE. l6l
61°, the northernmost of the Shetlands1. But here we are met by
the difficulty—how did Pytheas arrive at these results ? If they
were derived in each case from personal observation of the longest
day, his voyage must have extended over something like five
years—a supposition which is extremely improbable. If, on the
other hand, they were obtained from reports furnished by the
natives (which seems much more likely), such estimates would be
very untrustworthy, considering how vague the ideas of such
persons could not fail to be concerning the divisions of rime. It
is, no doubt, in favour of Pytheas' statements that they were
adopted by Hipparchus, because it shews that the great astronomer
had confidence in them ; and in order to facilitate our acceptance of
them it has been suggested, that only certain elementary observa-
tions are to be attributed to Pytheas, while the deductions from
them—among which the statements about the length of the
longest days in summer, and the greatest height to which the sun
rose above the horizon in winter, are to be included—should be
credited to Hipparchus. " It was sufficient for Hipparchus," it is
said, "if Pytheas declared that in a certain place and on a certain
day he had observed the sun at midday to be at a certain elevation
above the horizon. From these data Hipparchus could discover
the elevation of the sun at that spot at the winter solstice, and
could thence determine the latitude of the place8. This view of
the parts to be assigned to the earlier and the later astronomer
respectively would deliver us from the necessity of attributing to
Pytheas a greater amount of astronomical knowledge than he
probably possessed, and would also get rid of the difficulty
involved in the extreme length of time supposed to be occupied
by the expedition, if the observations which Strabo mentions were
made by him. Such a hypothesis deserves respectful attention,
but it cannot be said to receive any support from the authorities
which we possess. On the whole, when we take into account the
doubts which hang around the evidence for these observations,
and the small means of checking it which now exist, it seems safer
1 See Sir Clements Markham's paper on Pytheas in the Geographical
Journal^ vol. x. (1893) p. 518.
* Berger, Geschichte der Erdkundt, Pt. 3, p. 15.
T. II