Scarcely inferior to him in reputation was John Torrey. It was to
Torrey that Gray owed his first lessons in botany, and if the pupil
afterwards surpassed the master, it was because he was able to build on
the foundations which the master laid. John Torrey, born in New York
City in 1796, was the son of a Revolutionary soldier, and in early life
determined to become a machinist, but afterwards studied medicine and
began to practice in New York, taking up the study of botany as an
avocation. He found the profession of medicine uncongenial, and finally
abandoned it altogether for science, serving for many years as professor
of chemistry and botany at the College of Physicians and Surgeons in New
York City. The succeeding years brought him many honors, and saw many
works of importance issue from his hands.

The progress of the last century in the various branches of science is
an interesting study, and America has made no inconsiderable
contributions to every one of them. In astronomy, six names are worthy
of mention here. The first of these, John William Draper, was noted for
his devotion to many other lines of science, especially to photography,
and was the first person in the world to take a photograph of a human
being. His service to astronomy was in the application of photography to
that science. In 1840, he took the first photograph ever made of the
moon, and a few years later published his "Production of Light by Heat,"
an early and exceedingly important contribution to the subject of
spectrum analysis.

His work in astronomy and more especially in physics was carried
on most worthily by his son, Henry Draper, who, at his home at
Hastings-on-the-Hudson, built himself an observatory, mounting in it a
reflecting telescope, which he also made. His description of the
processes of grinding, polishing, silvering, testing and mounting it has
remained the standard work on the subject. With this telescope he took a
photograph of the moon which remains one of the best that has ever been
made. Among his other noteworthy achievements were his spectrum
photographs of 1872 and 1873, and in 1880 his photograph of the great
nebula in Orion, the first photograph of a nebula ever secured. Perhaps
the most brilliant discovery ever made in physical science by an
American was that by Draper in 1877, when he demonstrated the presence
of oxygen in the sun so conclusively that it could not be disputed. It
was a sort of _tour de force_ t