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states that “Every river appears to consist of a
main trunk, fed from a variety of branches, each
running in a valley proportioned to its size, and all of
them together forming a system of vallies, communicating
with one another, and having such a nice
adjustment of their declivities that none of them join
the principal valley on too high or too low a level,--a
circumstance which would be infinitely improbable if
each of these vallies were not the work of the stream
that flows in it.”
BIBLIOGRAPHY
I. ORIGINAL WORKS.
Playfair's chief writings are
Elements of Geometry (Edinburgh, 1795); Illustrations of
the Huttonian Theory of the Earth (Edinburgh, 1802);
Outlines of Natural Philosophy (Edinburgh, 1814); and
A General View of the Progress of Mathematical and
Physical Science Since the Revival of Letters in Europe,
vols. II and IV of Encyclopaedia Britannica, supp. (1816).
In The Works of John Playfair, James G. Playfair, ed.,
4 vols. (Edinburgh, 1822), “are contained all the publications
to which Mr. Playfair affixed his name, with the
exception of the Elements of Geometry, and of the Outlines
of Natural Philosophy, which were intended only for the use
of students, and although excellently adapted to their
object, would possess but little interest for the general
reader.” Vol. I contains a biographical memoir (see below)
and Illustrations of the Huttonian Theory; vol. II, the
Progress of Mathematical and Physical Science; vol. III,
various papers on mathematics and physics, plus a
“lithological survey of Schehallien” (in Scotland), all
of which had appeared either in Transactions of the Royal
Society or Transactions of the Royal Society of Edinburgh;
and vol. IV, various biographical accounts and reviews,
a biography of James Hutton being particularly important.
His works are listed in the British Museum General
Catalogue of Printed Books, CXCI, cols. 378-379.
II. SECONDARY LITERATURE.
The source for details of
the life of Playfair is F. Jeffrey, “Biographical Account
of the Late Professor Playfair,” prefixed to J. G. Playfair's
ed. of the Works (see above). See also B. B. Woodward,
in Dictionary of National Biography, XLV (1896), 413-414.
In reviewing Hutton's theory, Playfair's Illustrations is
nearly always referred to, since it is an essential part of
the authoritative exposition of Hutton's principles. See
particularly A. Geikie, The Founders of Geology (London,
1905), 280-316; and “Lamarck and Playfair,” in Geological
Magazine, 43 (1906), 145-153, 193-202; C. C. Gillispie,
Genesis and Geology (New York, 1951; repr. 1959), passim;
and R. J. Chorley et al., The History of the Study of
Landforms (London, 1964), 57-68. Playfair's original
contributions to geological knowledge are reviewed in
J. Challinor, “The Early Progress of British Geology--III,”
in Annals of Science, 10 (1954), 107-148, see 137-143.
JOHN CHALLINOR
PLAYFAIR, LYON (b. Chunar, India, 21 May 1818;
d. London, England, 29 May 1898), chemistry.
The son of a medical officer in the East India
Company, Playfair was brought up by relatives in
Scotland. In 1835 he became a medical student at the
Andersonian Institution, Glasgow, where Thomas
Graham awakened his interest in chemistry. Playfair
finished his medical studies at Edinburgh but had to
give up a medical career because of eczema. A
mercantile career in India was also abandoned after a
brief trial, and he returned to London to become
Graham's assistant.
Playfair spent 1839-1841 in Liebig's laboratory at
Giessen, where he did outstanding work on myristic
acid and caryophyllene; he increased his reputation by
translating Liebig's Die organische Chemie in ihre
Anwendung auf Agricultur und Physiologie into English.
After leaving Germany, Playfair became chemical
manager at the Primrose Mill, near Clitheroe,
Lancashire; but, sensing a decline in trade, he left in
the autumn of 1842 to become professor of chemistry
at the Royal Institution, Manchester. During
his three years there, Playfair collaborated with
Joule on laborious but ultimately fruitless work on
the atomic volumes of substances in solution; he also
worked with Bunsen on the analysis of blast-furnace
gases.
In 1842 Playfair's application for a chair in
chemistry at Toronto had elicited the unprecedented
intervention of the prime minister (Sir Robert Peel),
who offered Playfair an important post if he would
stay in Britain. This offer could not be implemented
until 1845, when he became chemist to the Geological
Survey and professor of chemistry at the new School
of Mines. Meanwhile, however, he was much in
governmental favor, and served on important Royal
Commissions on the Health of Towns and on the Irish
Potato Famine. In 1848 Playfair was elected a fellow
of the Royal Society and was subsequently Prince
Albert's chief adviser on the Great Exhibition of 1851.
While holding the post of inspector of schools of
science in London (1850-1858) he made his most
important discovery, the nitroprussides.
In 1858 Playfair accepted the chair of chemistry at
Edinburgh with high hopes, although in his eleven
years there he achieved little. In 1868, as a Liberal
party candidate, he was elected member of Parliament
for the universities of Edinburgh and St. Andrews, and
the rest of his life was spent in politics. He was active
in the cause of universal compulsory education (1870)
and took a prominent part in the reform of the Civil
Service; he was briefly postmaster general (1873-1874)
under Gladstone and deputy speaker of the House of
Commons (1880-1883). He was knighted on retirement