oyal Society, and was "a
kind of register of all new improvements in mathematics." His office
brought him into correspondence with all of the English scientists, and he
was influential in the publication of various important works, including
Branker's translation of the algebra by Rhonius, with notes by Pell, which
was the first work to contain the present English-American symbol of
division. He also helped in the publication of editions of Archimedes and
Apollonius, of Kersey's Algebra, and of the works of Wallis. His profession
was that of accountant and civil engineer, and he wrote three unimportant
works on mathematics (one published posthumously, and the others in 1652
and 1658).

Heinrich Christian Schumacher (1780-1850) was professor of astronomy at
Copenhagen and director of the observatory at Altona. His translation of
Carnot's _Geometrie de position_ (1807) brought him into personal relations
with Gauss, and the friendship was helpful to Schumacher. He was a member
of many learned societies and had a large circle of acquaintances. He
published numerous monographs and works on astronomy.

Gassendi (1592-1655) might well have been included by De Morgan in the
group, since he knew and was a friend of most of the important
mathematicians of his day. Like Mersenne, he was a minorite, but he was a
friend of Galileo and Kepler, and wrote a work under the title _Institutio
astronomica, juxta hypotheses Copernici, Tychonis-Brahaei et Ptolemaei_
(1645). He taught philosophy at Aix, and was later professor of mathematics
at the College Royal at Paris.

Burnet is the Bishop Gilbert Burnet (1643-1715) who was so strongly
anti-Romanistic that he left England during the reign of James II and
joined the ranks of the Prince of Orange. William made him bishop of
Salisbury.

[191] There is some substantial basis for De Morgan's doubts as to the
connection of that _mirandula_ of his age, Sir Kenelm Digby (1603-1665),
with the famous _poudre de sympathie_. It is true that he was just the one
to prepare such a powder. A dilletante in everything,--learning, war,
diplomacy, religion, letters, and science--he was the one to exploit a
fraud of this nature. He was an astrologer, an alchemist, and a fabricator
of tales, and well did Henry Stubbes characterize him as "the very Pliny of
our age for lying." He first speaks of the powder in a lecture given at
Montpellier in 1658, and in the same year he published the address at Paris
und