imagined that all the metals laboured under disease, with the
exception of gold, which was the only one in perfect health. He
affirmed, that the secret of the philosopher's stone had been more
than once discovered; but that the ancient and wise men who had hit
upon it, would never, by word or writing, communicate it to men,
because of their unworthiness and incredulity. [His "sum of
perfection," or instructions to students to aid them in the laborious
search for the stone and elixir, has been translated into most of the
languages of Europe. An English translation, by a great enthusiast in
alchymy, one Richard Russell, was published in London in 1686. The
preface is dated eight years previously, from the house of the
alchymist, "at the Star, in Newmarket, in Wapping, near the Dock." His
design in undertaking the translation was, as he informs us, to expose
the false pretences of the many ignorant pretenders to the science who
abounded in his day.] But the life of Geber, though spent in the
pursuit of this vain chimera, was not altogether useless. He stumbled
upon discoveries which he did not seek, and science is indebted to him
for the first mention of corrosive sublimate, the red oxide of
mercury, nitric acid, and the nitrate of silver. [Article, Geber,
"Biographie Universelle."]

For more than two hundred years after the death of Geber, the
Arabian philosophers devoted themselves to the study of alchymy,
joining with it that of astrology. Of these the most celebrated was

ALFARABI.

Alfarabi flourished at the commencement of the tenth century, and
enjoyed the reputation of being one of the most learned men of his
age. He spent his life in travelling from country to country, that