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444
MODERN TIMES.
the present day has been established on the abundance of
newly-discovered facts which have enriched the natural
sciences during the nineteenth century, and in the knowledge
of their mutual relationships and common laws,
which has rendered possible a simplified view of the life of
nature.
In bringing forward certain facts from the history of the
various natural sciences I desire only to indicate the course
of their development in a few words.
Already in the eighteenth century attempts had been
made to classify minerals on a rational basis. Their external
characteristics and resemblances formed the foundation of
the arrangements of LlNN^US and WALLERIUS. On the
other hand AXEL F. CRONSTEDT, the Swede, regarded their
chemical constitution as all-important; ABRAHAM GOTTLOB
WERNER, the Saxon counsellor of mines, then made a
classification of them, founded both upon their chemical
and physical peculiarities, and upon their external form.
To him is due the credit of having defined the limits of
oryktology and geognosy and of having founded the latter
science.
The improvement of the science of crystallography* was
commenced by ROME DE L'ISLE and HAUY and was successfully
carried on by WEISS and MOHS. Others studied
the chemical, optical, and electrical properties of certain
minerals, and also the phosphorescence and phenomena of
polarization observed in them. The appreciation of the
value of chemistry as an aid to mineralogy led to the
intimate association of these two sciences, which proved to
be suggestive and advantageous in many ways.
LEOPOLD VON BUCH did the work of a pioneer in the
subjects of geognosy and geology. At the same time, too,
the subject of the formation of fossils, to which
SCHEUCHZER was the first to direct attention, was
* CUVIER: Geschichte der Fortschritte in den Naturwissenschaften seit 1789,
Deutsche Ubers, Leipzig, 1828, 4 Bde. ;f