sink into the minds of men; and as
scientific progress was vastly slower then than it is now, we find not
only all priests but even some astronomers one hundred years afterwards
still imagining the earth to be at rest. And among them was a very
eminent one, Tycho Brahe.

It is interesting to note, moreover, that the argument about the motion
of the earth being contrary to Scripture appealed not only to
ecclesiastics in those days, but to scientific men also; and Tycho
Brahe, being a man of great piety, and highly superstitious also, was so
much influenced by it, that he endeavoured to devise some scheme by
which the chief practical advantages of the Copernican system could be
retained, and yet the earth be kept still at the centre of the whole.
This was done by making all the celestial sphere, with stars and
everything, rotate round the earth once a day, as in the Ptolemaic
scheme; and then besides this making all the planets revolve round the
sun, and this to revolve round the earth. Such is the Tychonic system.

So far as _relative_ motion is concerned it comes to the same thing;
just as when you drop a book you may say either that the earth rises to
meet the book, or that the book falls to meet the earth. Or when a fly
buzzes round your head, you may say that you are revolving round the
fly. But the absurdity of making the whole gigantic system of sun and
planets and stars revolve round our insignificant earth was too great to
be swallowed by other astronomers after they had once had a taste of the
Copernican theory; and accordingly the Tychonic system died a speedy and
an easy death at the same time as its inventor.

Wherein then lay the magnitude of the man?--not in his theories, which
were puerile, but in his observations, which were magnificent. He was
the first observational astronomer, the founder of the splendid system
of practical astronomy which has culminated in the present Greenwich
Observatory.

[Illustration: FIG. 16.--Tychonic system showing the sun with all the
planets revolving round the earth.]

Up to Tycho the only astronomical measurements had been of the rudest
kind. Copernicus even improved upon what had gone before, with measuring
rules made with his own hands. Ptolemy's observations could never be
trusted to half a degree. Tycho introduced accuracy before undreamed of,
and though his measurements, reckoned by modern ideas, are of course
almost ludicrously rough (remember no such thing as a