uld have given him a high rank among the original
inquirers of his age; but when we consider him also as the discoverer
of the three great laws which bear his name, we must assign him a rank
next to that of Newton. The history of science does not present us with
any discoveries more truly original, or which required for their
establishment a more powerful and vigorous mind. The speculations of his
predecessors afforded him no assistance. From the cumbrous machinery
adopted by Copernicus, Kepler passed, at one step, to an elliptical
orbit, with the sun in one of its foci, and from that moment astronomy
became a demonstrative science. The splendid discoveries of Newton
sprung immediately from those of Kepler, and completed the great chain
of truths which constitute the laws of the planetary system. The
eccentricity and boldness of Kepler's powers form a striking contrast
with the calm intellect and the enduring patience of Newton. The bright
spark which the genius of the one elicited, was fostered by the sagacity
of the other into a steady and a permanent flame.

Kepler has fortunately left behind him a full account of the methods by
which he arrived at his great discoveries. What other philosophers have
studiously concealed, Kepler has openly avowed, and minutely detailed;
and we have no hesitation in considering these details as the most
valuable present that has ever been given to science, and as deserving
the careful study of all who seek to emulate his immortal achievements.
It has been asserted that Newton made his discoveries by following a
different method; but this is a mere assumption, as Newton has never
favoured the world with any account of the erroneous speculations and
the frequent failures which must have preceded his ultimate success. Had
Kepler done the same, by recording only the final steps of his
inquiries, his method of investigation would have obtained the highest
celebrity, and would have been held up to future ages as a pattern for
their imitation. But such was the candour of his mind, and such his
inordinate love of truth, that he not only recorded his wildest fancies,
but emblazoned even his greatest errors. If Newton had indulged us with
the same insight into his physical inquiries, we should have witnessed
the same processes which were employed by Kepler, modified only by the
different characters and intensities of their imaginative powers.

When Kepler directed his mind to the discovery of a