Background
John Playfair was born at Benvie, near Dundee, where his father, Reverend James Playfair was a kirk minister. On the death of his father in 1772, he succeeded him in the living of Benvie.
1819
John Playfair. Line engraving by Stewart, after P. Morris.
1819
John Playfair. Stipple engraving by J. Thomson.
1843
Bust of Professor John Playfair (1748-1819), mathematician and geologist/physicist, made by Sir Francis Legatt Chantrey Benjamin Cheverton.
University of St Andrews, St Andrews, Scotland, United Kingdom
Playfair graduated from the University of St Andrews with a Master of Arts degree in 1765.
John Playfair. Stipple engraving by Holl.
John Playfair. Stipple engraving after H. Raeburn.
Royal Society of London, London, England, United Kingdom
In 1807 Playfair was elected a Fellow of the Royal Society of London.
A title page of the Huttonian Theory of the Earth by J. Playfair.
Royal Society of Edinburgh, 22–26 George Street, Edinburgh, EH2 2PQ, Scotland, United Kingdom
In 1783, Playfair became a member and co-founder of the Royal Society of Edinburgh.
St. Mary's College, St Andrews, St Andrews, Fife, Scotland, United Kingdom
Playfair undertook his theological studies at St. Mary's College, St Andrews and completed his studies in 1769.
Calton Hill, Edinburgh, scotland, United Kingdom
Monument to John Playfair on Calton Hill.
https://www.amazon.com/Works-John-Playfair-Measurements-Investigation/dp/134637404X/ref=sr_1_6?keywords=John+Playfair&qid=1580712462&sr=8-6
1825
geologist mathematician naturalist physicist scientist
John Playfair was born at Benvie, near Dundee, where his father, Reverend James Playfair was a kirk minister. On the death of his father in 1772, he succeeded him in the living of Benvie.
Playfair was educated by his father at home until the age of fourteen and was sent to the University of St. Andrews. Playfair was awarded a scholarship to the University in 1762, and there his aptitude and keenness to study gained him both the respect and friendship of his professors. His progress in the mathematical sciences was so rapid that the professor of natural philosophy, Professor Wilkie, when suffering from an illness, found him to be the person best qualified to deliver his lectures on natural philosophy. Playfair graduated from the University of St. Andrews with a Master of Arts degree in 1765.
After that, Playfair undertook his theological studies at St. Mary's College, St Andrews. On completion of his studies in 1769, he left the University, and from then on spent much of his time until 1773 in Edinburgh.
On the death of his father in 1772, Playfair succeeded him in the living of Benvie, which he resigned in 1782 to become a tutor for a private family. From 1785 to 1805 Playfair held a professorship of mathematics at the University of Edinburgh. He edited the Transactions of the Royal Society of Edinburgh for many years, and most of his papers appeared in that periodical. They were concerned almost entirely with mathematics, physics, and biographies. His Elements of Geometry was published in 1795.
Following the death in 1797 of his friend James Hutton, Playfair proceeded to make a careful analysis, clarification, and amplification of Hutton’s Theory of the Earth, which had originally been presented as a paper read in 1785 to the Royal Society of Edinburgh and was expanded into the two-volume work of 1795.
Playfair’s efforts resulted in Illustrations of the Huttonian Theory of the Earth (1802). In 1805 he became professor of natural philosophy at Edinburgh, where his lectures now embraced physics and astronomy. His Outlines of Natural Philosophy was published in 1814.
Playfair’s professional work was thus in mathematics and physics. His book on geometry is a full presentation of the first six books of Euclid, with much additional material. The formal treatment of linear parallelism requires axioms. Finding Euclid’s axioms on this matter to be unsatisfactory, Playfair proposed “that two straight lines, which intersect one another, cannot be both parallel to the same straight line.” This is what became known as “Playfair’s axiom,” as it is given in his Elements of Geometry.
Playfair lived well into this second period of activity but did not take any part in it. A project that was very much in his mind was the preparation of a comprehensive work on geology, which was to have been a greatly amplified edition of his Illustrations. The peace of 1815 enabled Playfair to make an extensive tour of France, Switzerland, and Italy, in order to extend his observations for this purpose; but although we have details of the journey, nothing of the projected work was composed.
By the end of the eighteenth century the rocks of Britain had been classified into two main groups, the Primary (at first called “Primitive”) and the Secondary. This division was based on observed superposition, particular attention being paid to unconformities and, as the names show, on the consequently inferred relative ages. The grouping is, in fact, a natural twofold occurrence in many regions, but the stratigraphical (time) gap is not everywhere at the same part of the general succession; for instance, over much of Scotland, it is below the Old Red Sandstone, in northwest England below the Carboniferous, and in south Wales and southwest England below the Permo-Triassic or the Lias.
This discrepancy was not known at the time, and long after the end of the eighteenth century the Devonian and Carboniferous rocks of Devon and Cornwall were thought to be equivalent in age to rocks below the Old Red Sandstone elsewhere. As for the igneous rocks, the large granite masses were generally believed to be among the most ancient; but since their intrusive nature had been demonstrated, this assumption was found to rest on no very secure basis. They had not, however, yet been discovered as being intrusive into any but Primary rocks. The smaller intrusions, dikes, and sills, found among Secondary rocks, were necessarily accepted as being comparatively young. In fact, the logical position had been reached of preliminary classification of rocks, regardless of age, into the two lithological groups: igneous and sedimentary.
It is not surprising that no classification of the Primary rocks had been attempted. Particular rocks were simply described by such lithological or mining terms as schistus, slate, killas, and clay-slate, which had no very precise meaning. Within the Secondary group, a very rough succession from the Coal Measures to the Chalk had been given by John Strachey (1725), and John Michell (1788) had offered a more accurate succession of the same range of strata. In those regions where the Carboniferous succession had been observed - in Scotland (by John Williams, 1789) and, particularly, in Derbyshire (by John Whitehurst, 1778) - the Limestone was found to underlie the Coal Measures, with Millstone Grit (if present) intermediate. It does not seem that the stratigraphic relation of the Old Red Sandstone (the equivalent in age to the marine Devonian) to the Carboniferous rocks had been observed.
The question arises of the extent to which a geological map of Britain could have been constructed from the observations recorded up to 1802. The map would have been very sketchy; and no one made any serious attempt at such a compilation, although William George Maton drew a very inaccurate “mineralogical map” of southwest England in 1797. The geological researches of William Smith had begun about 1790. In 1801 he colored geologically a small map of England and Wales, and in 1815 his great map of England and Wales was published.
(Volume 2)
1819(Volume 1)
1819(Volume 3)
1822(Volume 4)
1822(Volume 2)
1814Playfair's father was a Church of Scotland minister and educated him at home until the age of fourteen, with the purpose to send him to the University of St Andrews to study for a general degree with the aim of entering the Church. Consequently, John Playfair was licensed to preach by Dundee Presbytery in 1770.
Playfair's views were strongly influenced by luminaries of the Scottish Enlightenment, part of which he became after his graduation from St Mary's College and after moving to Edinburgh. Later in the course of his scientific career, his views were divided by two eras in the history of geological investigation. His own observations, inferences, and expressions were the final contributions to the first era and can be classed under three heads.
First, Playfair realized the importance of unconformity in the manifestation of the geological cycle; and he searched throughout Britain for signs of this kind of structural relation, to add to the instances already recorded by Hutton. Unconformity implies the operation of the “geological cycle” - deposition, deformation, emergence, erosion, submergence, and deposition. The concept of the geological cycle is the essence of Hutton’s theory.
Thus, Playfair observed the unconformity between the Permo-Triassic and Devonian to be seen at places on the coasts of both north and south Devonshire, and that between the Old Red Sandstone and Dalradian (“Primary schistus”) on the east and west coasts of Scotland. He graphically described the unconformity between the Carboniferous Limestone and pre-Devonian rocks in the Ingle-borough district of Yorkshire (the British region that shows this phenomenon most clearly) and gave a glimpse of the structure of the English Lake District with its rim of unconformable Carboniferous rocks.
Second, Playfair made miscellaneous observations, of which the more significant was the fossiliferous nature of the Primary Devonian limestone at Plymouth; the fractures, curiously plane without shattering, in the Old Red Sandstone conglomerate at Oban in Scotland; the general constancy of the east-northeast/west-southwest trend in the structure of the older rocks of Britain; the form of the intrusive sill at Salisbury Craigs and the metamorphism at the volcanic neck of Arthur’s Seat, in the neighborhood of Edinburgh; the small-scale folding in the Dalradian schist of Ben Lawers, which he noticed resembled that in the Alpine region; intrusive veins in Ayrshire and Arran and the contact metamorphism produced by them; the flint-gravels of southern England as the residue of dissolved flinty chalk; and the submerged forest of the Lincolnshire coast.
Third, Playfair’s book used many more-or-less ordinary words (arenaceous, consolidated, petrifaction) in modern geological senses, most of them probably for the first time, and introduced several highly significant terms into geological literature (geological cycle, igneous origin).
Quotations:
"Amid all the revolutions of the globe, the economy of Nature has been uniform, ... and her laws are the only things that have resisted the general movement. The rivers and the rocks, the seas and the continents, have been changed in all their parts; but the laws which direct those changes, and the rules to which they are subject, have remained invariably the same."
"Every river appears to consist of a main trunk, fed from a variety of branches, each running in a valley proportional 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."
"It is admitted, on all hands, that the Scriptures are not intended to resolve physical questions, or to explain matters in no way related to the morality of human actions; and if, in consequence of this principle, a considerable latitude of interpretation were not allowed, we should continue at this moment to believe, that the earth is flat; that the sun moves round the earth; and that the circumference of a circle is no more than three times its diameter."
"It was one thing to declare that we had not yet discovered the traces of a beginning, and another to deny that the earth ever had a beginning."
"The Author of nature has not given laws to the universe, which, like the institutions of men, carry in themselves the elements of their own destruction; he has not permitted in his works any symptom of infancy or of old age or any sign by which we may estimate either their future or their past duration. He may put an end, as he no doubt gave a beginning, to the present system at some determinate period of time; but we may rest assured, that this great catastrophe will not be brought about by the laws now existing and that it is not indicated by anything which we perceive."
"The bottom of the sea is the great laboratory, where loose materials are mineralized and formed into stone."
"The powers which tend to preserve, and those which tend to change the condition of the earth's surface, are never in equilibrio; the latter are, in all cases, the most powerful, and, in respect of the former, are like living in comparison of dead forces. Hence the law of decay is one which suffers no exception: The elements of all bodies were once loose and unconnected, and to the same state nature has appointed that they should all return... TIME performs the office of integrating the infinitesimal parts of which this progression is made up; it collects them into one sum, and produces from them an amount greater than any that can be assigned."
In 1783, Playfair became a member and co-founder of the Royal Society of Edinburgh. In 1807 Playfair was elected a Fellow of the Royal Society of London.
Playfair's amicable character made him a popular personality. According to the opinion of his friend and colleagues, "he possessed a cordial combination of the two aristocracies of rank and of letters." Lord Henry Cockburn wrote that "Playfair was admired by all men, and beloved by all women, of whose virtues and intellect he was always champion, society felt itself the happier and the more respectable from his presence."
His nephew wrote the following: "... though the most social of human beings, and the most disposed to encourage and sympathize with the gaiety and joviality of others, his own spirits were in general rather cheerful than gay, or at least never rose to any turbulence or tumult of merriment... His own satisfaction might generally be traced in the slow and temperate smile, gradually mantling over his benevolent and intelligent features, and lighting up the countenance of the Sage with the expression of the mildest and most genuine philanthropy."
Physical Characteristics: Towards the end of his life, Playfair suffered from rheumatism and had a severe attack during the early part of 1797.
Quotes from others about the person
Archibald Geikie remarked (1905): “How different would geological literature be to-day if men had tried to think and write like Playfair!”
James George Playfair (his nephew), who edited The Works of John Playfair in 1822 wrote: "... we believe we hazard nothing in saying that he was one of the most learned mathematicians of his age, and among the first, if not the very first, who introduced the beautiful discoveries of the later continental geometers to the knowledge of his countrymen, and gave their just value and true place, in the scheme of European knowledge, to those important improvements by which the whole aspect of the abstract sciences has been renovated since the days of our illustrious Newton... He possessed, indeed, in the highest degree, all characteristics both of a fine and powerful understanding, at once penetrating and vigilant, but more distinguished, perhaps, for the caution on sureness of its march, than for the brilliancy or rapidity of its movements, and guided and adorned through all its progress by the most genuine enthusiasm for all that is grand, and the justest taste for all that is beautiful in the Truth or the Intellectual Energy with which he was habitually conversant."
Playfair's brothers were architect James Playfair, solicitor Robert Playfair, and engineer William Playfair. His nephew, William Henry Playfair (1790–1857) was an eminent architect in Scotland. In later life, he admired and proposed to the wealthy widow Jane Apreece, but she turned him down and married Sir Humphry Davy.