tural Law in the Spiritual World_,
the argument of which was that the scientific principle of continuity
extended from the physical world to the spiritual. Before the book
issued from the press (1883), a sudden invitation from the African Lakes
Company drew Drummond away to Central Africa. Upon his return in the
following year he found himself famous. Large bodies of serious readers,
alike among the religious and the scientific classes, discovered in
_Natural Law_ the common standing-ground which they needed; and the
universality of the demand proved, if nothing more, the seasonableness
of its publication. Drummond continued to be actively interested in
missionary and other movements among the Free Church students. In 1888
he published _Tropical Africa_, a valuable digest of information. In
1890 he travelled in Australia, and in 1893 delivered the Lowell
Lectures at Boston. It had been his intention to reserve them for mature
revision, but an attempted piracy compelled him to hasten their
publication, and they appeared in 1894 under the title of _The Ascent of
Man_. Their object was to vindicate for altruism, or the disinterested
care and compassion of animals for each other, an important part in
effecting "the survival of the fittest," a thesis previously maintained
by Professor John Fiske. Drummond's health failed shortly afterwards,
and he died on the 11th of March 1897. His character was full of charm.
His writings were too nicely adapted to the needs of his own day to
justify the expectation that they would long survive it, but few men
exercised more religious influence in their own generation, especially
on young men.

DRUMMOND, THOMAS (1797-1840), British inventor and administrator, was
born at Edinburgh on the 10th of October 1797, and was educated at the
high school there. He was appointed to a cadetship at the Royal Military
Academy, Woolwich, in 1813; and in 1815 he entered the Royal Engineers.
In 1819, when meditating the renunciation of military service for the
bar, he made the acquaintance of Colonel T. F. Colby (1784-1852), from
whom in the following year he received an appointment on the
trigonometrical survey of Great Britain. During his winters in London he
attended the chemical lectures of W. T. Brande and M. Faraday at the
Royal Institution, and the mention at one of these of the brilliant
luminosity of lime when incandescent suggested to him the employment of
the lime light for making distant