y a quadrant and a sextant. Observed at Augsburg
and Wittenberg. Studied alchemy, but was recalled to astronomy by the
appearance of a new star. Overcame his aristocratic prejudices, and
delivered a course of lectures at Copenhagen, at the request of the
king. After this he married a peasant girl. Again travelled and observed
in Germany. In 1576 was sent for to Denmark by Frederick II., and
established in the island of Huen, with an endowment enabling him to
devote his life to astronomy. Built Uraniburg, furnished it with
splendid instruments, and became the founder of accurate instrumental
astronomy. His theories were poor, but his observations were admirable.
In 1592 Frederick died, and five years later, Tycho was impoverished and
practically banished. After wandering till 1599, he was invited to
Prague by the Emperor Rudolf, and there received John Kepler among other
pupils. But the sentence of exile was too severe, and he died in 1601,
aged 54 years.

A man of strong character, untiring energy, and devotion to accuracy,
his influence on astronomy has been immense.

LECTURE II

TYCHO BRAHE AND THE EARLIEST OBSERVATORY

We have seen how Copernicus placed the earth in its true position in the
solar system, making it merely one of a number of other worlds revolving
about a central luminary. And observe that there are two phenomena to be
thus accounted for and explained: first, the diurnal revolution of the
heavens; second, the annual motion of the sun among the stars.

The effect of the diurnal motion is conspicuous to every one, and
explains the rising, southing, and setting of the whole visible
firmament. The effect of the annual motion, _i.e._ of the apparent
annual motion, of the sun among the stars, is less obvious, but it may
be followed easily enough by observing the stars visible at any given
time of evening at different seasons of the year. At midnight, for
instance, the position of the sun is definite, viz. due north always,
but the constellation which at that time is due south or is rising or
setting varies with the time of year; an interval of one month producing
just the same effect on the appearance of the constellations as an
interval of two hours does (because the day contains twice as many hours
as the year contains months), _e.g._ the sky looks the same at midnight
on the 1st of October as it does at 10 p.m. on the 1st of November.

All these simple consequences of the geocentric as oppos