hey are the effect of water, which, cutting for itself a new route, has
denuded the valleys, the strata being of different kinds, some soft,
some hard. The winds and waters disintegrate the one, but leave the
other intact. Most of the eminences of the earth have had this latter
origin. It would require a long period of time for all such changes to
be accomplished, during which the mountains themselves might be somewhat
diminished in size. But that water has been the main cause of these
effects is proved by the existence of fossil remains of aquatic and
other animals on many mountains." Avicenna also explains the nature of
petrifying or incrusting waters, and mentions aerolites, out of one of
which a sword-blade was made, but he adds that the metal was too brittle
to be of any use. A mere catalogue of some of the works of Avicenna will
indicate the condition of Arabian attainment. 1. On the Utility and
Advantage of Science; 2. Of Health and Remedies; 3. Canons of Physic; 4.
On Astronomical Observations; 5. Mathematical Theorems; 6. On the Arabic
Language and its Properties; 7. On the Origin of the Soul and
Resurrection of the Body; 8. Demonstration of Collateral Lines on the
Sphere; 9. An Abridgment of Euclid; 10. On Finity and Infinity; 11. On
Physics and Metaphysics; 12. An Encyclopaedia of Human Knowledge, in 20
vols., etc., etc. The perusal of such a catalogue is sufficient to
excite profound attention when we remember the contemporaneous state of
Europe.

[Sidenote: Effect of the search for the elixir on practical medicine.]

The pursuit of the elixir made a well-marked impression upon Arab
experimental science, confirming it in its medical application. At the
foundation of this application lay the principle that it is possible to
relieve the diseases of the human body by purely material means. As the
science advanced it gradually shook off its fetichisms, the spiritual
receding into insignificance, the material coming into bolder relief.
Not, however, without great difficulty was a way forced for the great
doctrine that the influence of substances on the constitution of man is
altogether of a material kind, and not at all due to any indwelling or
animating spirit; that it is of no kind of use to practise incantations
over drugs, or to repeat prayers over the mortar in which medicines are
being compounded, since the effect will be the same, whether this has
been done or not; that there is no kind of efficacy in amul