s Character--His
Astrological Writings and Opinions considered--His Character as an
Astronomer and a Philosopher--The Splendour of his
Discoveries--Account of his Methods of Investigating Truth._

Although the labours of Kepler were frequently interrupted by severe and
long-continued indisposition, as well as by the pecuniary embarrassments
in which he was constantly involved, yet the ardour and power of his
mind enabled him to surmount all the difficulties of his position. Not
only did he bring to a successful completion the leading inquiries
which he had begun, but he found leisure for composing an immense number
of works more or less connected with the subject of his studies. Between
1594, when he published his Kalendar at Gratz, and 1630, the year of his
death, he published no fewer than _thirty-three_ separate works; and he
left behind him _twenty-two_ volumes of manuscripts, _seven_ of which
contain his epistolary correspondence.

The celebrated astronomer Hevelius, who was a cotemporary of Louis
Kepler, purchased all these manuscripts from Kepler's representatives.
At the death of Hevelius they were bought by M. Gottlieb Hansch, a
zealous mathematician, who was desirous of giving them to the world. For
this purpose he issued a prospectus in 1714 for publishing them by
subscription, in 22 volumes folio; but this plan having failed, he was
introduced to Charles VI., who liberally obtained for him 1000 ducats to
defray the expense of the publication, and an annual pension of 300
florins. With such encouragement, Hansch published in 1718, in one
volume folio, the correspondence of Kepler, entitled "_Epistolae ad
Joannem Keplerum, insertis ad easdem responsionibus Keplerianis,
quidquid hactenus reperiri potuerunt, opus novum, et cum Jo. Kepleri
vita._"

The expenses of this volume unfortunately exhausted the 1000 ducats
which had been granted by the Emperor, and, instead of being able to
publish the rest of the MSS., Hansch was under the necessity of pledging
them for 828 florins. Under these difficulties he addressed himself in
vain to the celebrated Wolfius, to the Royal Society of London, and to
other bodies that were likely to interest themselves in such a subject.
In 1761, when M. De Murr of Nuremberg was in London, he made great
exertions to obtain the MSS., and Dr Bradley is said to have been on the
eve of purchasing them. The competition probably raised the demands of
the proprietor, in who