142 BIOGRAPHICAL SKETCHES.
most powerful speakers in favour of the accused-was not concluded till about
midnight of the second day, when his opponents were outvoted by ninety-six to
eighty-four.
Mr. Leslie now took possession of the Mathematical chair without further
opposition. Finding the class apparatus very deficient, he immediately set about
remedying the defect, by making extensive collections and adding several instruments
of his own invention ; and throughout the whole period of his professorship,
much of his leisure was devoted to the accomplishment of still further
improvements. In 1810, by the aid of the hygrometer-one of his ingenious
contrivances-he arrived at the discovery of artificial congelation, or the mode
of converting water and mercury into, ice, which has been characterised as a
process “ singularly beautiful.” In 181 9, on the death of Professor Playfair, he
obtained the chair of Natural Philosophy, and thereby found his sphere of usefulness
extended, and a wider field for the display of his talents.
The various works produced by Mr. Leslie are as follow :-In 1809, “ Elements
of Geometry,” which immediately became a class book-1813, an “Account
of Experiments and Instruments depending on the relation of Air to Heat
and Moisture ”-1817, “ Philosophy of Arithmetic, exhibiting a progressive
view of the Theory and Progress of Calculation”-l821, “ Geometrical Analysis,
and Geometry of Curve Lines, being volume second of a course of Mathematics,
and designed as an Introduction to the Study of Natural Philosophy,” for the
use of his class, of which only one volume appeared-1828, “Rudiments of
Geometry,” a small octavo, designed for popular use. Besides these, he wrote
many articles in the Edinburgh Review ; in Nicholson’s Philosophical Journal ; in \
the Transactions of the Royal Society of Edinburgh ; and furnished several valuable
treatises on different branches of physics in the Supplement to the Emyclopledia
Britannica. In the seventh edition of that work, begun in 1829, he-wrote
a “ Discourse on the History of Mathematics and Physical Science during the
Eighteenth Century,” which is allowed to be the most pleasing and faultless of
all his writings.
In 1832, on the recommendation of Lord Brougham, then Lord Chancellor,
Mr. Leslie was created a Knight of the Guelphic Order, and a similar honour
was conferred on Herschel, Bell, Ivory, Rrewster, South, Nicholas, and other
iudividuals equally eminent for their attainments ; but he did not long enjoy
the honour conferred on him. He had purchased an estate, called Coates, near
his native place, where, by exposing himself to wet while superintending some
improvements, he caught a severe cold, which terminated in his death on the
3d November 1832.
All
have admired the invqntive fertility of his genius-his extensive knowledge
and vigorous mind. As a writer, however, his style has been criticised ; and
he has been accused as somewhat illiberal in his estimate of kindred merit,
while he is represented to have been credulous in matters of common life, and
sceptical in science. “ His faults,” says his biographer, ‘‘ were far more than
.
The character of Sir John has been subject to some littls stricture.