overthrow of Stahl's famous theory and the establishment of
modern chemistry, we must review the work of another great
chemist, Karl Wilhelm Scheele (1742-1786), of Sweden, who
discovered oxygen quite independently, although later than
Priestley. In the matter of brilliant discoveries in a brief
space of time Scheele probably eclipsed all his great
contemporaries. He had a veritable genius for interpreting
chemical reactions and discovering new substances, in this
respect rivalling Priestley himself. Unlike Priestley, however,
he planned all his experiments along the lines of definite
theories from the beginning, the results obtained being the
logical outcome of a predetermined plan.

Scheele was the son of a merchant of Stralsund, Pomerania, which
then belonged to Sweden. As a boy in school he showed so little
aptitude for the study of languages that he was apprenticed to an
apothecary at the age of fourteen. In this work he became at
once greatly interested, and, when not attending to his duties in
the dispensary, he was busy day and night making experiments or
studying books on chemistry. In 1775, still employed as an
apothecary, he moved to Stockholm, and soon after he sent to
Bergman, the leading chemist of Sweden, his first discovery--that
of tartaric acid, which he had isolated from cream of tartar.
This was the beginning of his career of discovery, and from that
time on until his death he sent forth accounts of new discoveries
almost uninterruptedly. Meanwhile he was performing the duties of
an ordinary apothecary, and struggling against poverty. His
treatise upon Air and Fire appeared in 1777. In this remarkable
book he tells of his discovery of oxygen--"empyreal" or
"fire-air," as he calls it--which he seems to have made