PLAYFAIR, JOHK. 



PLAYFAIR, LYON. 



1827, by Cotter. There { an excellent translation by Bonnd Thorn. 

 ton. 'The Comedies of PUutos translated into familiar Blank Verse,' 

 2 Tola. 8vo, 1-ouil., 1767. It was continued by Hichard Warner, 

 Tola. iii. and IT., STO, Lond., 1772 ; rol. v., 8vo, Lnnil., 1774. 



PI.AYK A IK, JOHN, was born at Brnvie in Forfarshire, on the 10th 

 of March 174S. His father wai minister of the united parishes of 

 Uff and Bcnrie, and to htm he was indebted for his education till he 

 attained the age of fourteen, when he wai vent to the University of 

 St. Andrew. Here he icon became remarkable for his love of study, 

 bat more particularly for the rapid progress which he made in mathe- 

 matics and natural philosophy. So great indeed was his early pro- 

 ficiency that, very few yoan after his matriculation, Dr. Wilkie, the 

 professor of natural philosophy, finding himself, through indisposition, 

 unable to discharge the duties of his office, delegated them to Playfair. 

 In 1766, when eighteen years old, ho distinguished himself as a candi- 

 date for the professorship of mathematics in Horischal College, Aber- 

 deen. The examination was a strict one, and lasted eleven days, 

 some say fourteen. The candidates were six in number, of whom two 

 only were judged to have excelled him, namely, the Rev. Dr. Trail, on 

 whom the appointment was conferred, and who attributed his success 

 solely to the disparity of years, and Dr. Hamilton, who subsequently 

 filled the same appointment with much credit. 



Upon tbe death of Dr. Wilkie in 1772 Mr. Playfair offered himself 

 as his successor, but wan again unsuccessful. The same year the 

 responsibility of providing for the support ' of his mother and her 

 family having devolved upon him by the decease of his father, he 

 considered it his duty to adopt the clerical profession, notwithstanding 

 his intense and growing predilection for scientific pursuits. Having 

 accordingly applied for and obtained the living of Liff and Ben vie, he 

 entered in 1773 upon the duties of his ministry, in the discharge of 

 which and in the education of his younger brothers his time was 

 chiefly occupied during tho following nine years. Such a mode of life 

 was not unfavourable to the prosecution of those researches in which 

 be bad already engaged with BO much avidity. The first fruit of his 

 leisure hours in this respect was a paper communicated to the Royal 

 Society of London, and inserted in their ' Transactions ' for the year 

 1779, 'On the Arithmetic of Impossible Quantities,' which evinced a 

 greater taste for purely analytical investigation than can be conceded 

 to the generality of British mathematicians of that day. A subject 

 involving difficulties of a higher order had some years previously 

 engaged his attention, while on a visit at Schehallion to witness the 

 experiments of Dr. Maskelyne on the attraction of the mountains in 

 that district, on which occasion he made the acquaintance and acquired 

 the friendship of that astronomer. Hia investigations upon this subject 

 are contained in his 'Account of the Lithological Survey of Schehallion,' 

 published in the 'London Philosophical Transactions for 1811. 



He resigned his living in 1782 to superintend the education of the 

 sons of Mr. Ferguson of Raith ; and in 1786 he was appointed professor 

 of mathematics, jointly with Dr. Adam Ferguson, in the University of 

 Edinburgh, an appointment previously held by Dugald Stewart. In 

 1789 be succeeded Dr. Gregory as secretary to the physical class of the 

 Edinburgh Royal Society ; and about the same time, owing to the 

 illness of Dr. Robison, the duties of general secretary and the labour 

 of arranging the society's memoirs for publication devolved chiefly 

 upon him ; but the nominal appointment of general secretary was not 

 conferred upon htm till the death of Dr. Robiaon in 1805, whom ho 

 likewise succeeded as professor of natural philosophy in the University 

 of Edinburgh. This obliged him to resign the chair of mathematics, 

 on which occasion tbe mathematical class expressed their sense of 

 the obligation they were under for his past exertions in their behalf 

 by presenting him with a valuable astronomical circle, now in the 

 observatory of the Astronomical Institution. The dispute which 

 followed the nomination of Mr. Leslie to the vacant chair has been 

 already noticed under LESLIE, SIB JOIIN (the date of whose appoint- 

 ment to the chair of natural philosophy was 1819, and not 1809, as is 

 there incorrectly stated). The extreme illibcrality of the measures 

 adopted by Mr. Leslie's opponents, and the manifest desiro of tho 

 clergy to cripple scientific emulation by restricting to their own class 

 appointment* totally unconnected with theology, and hitherto filled 

 by laymen with honour and advantage, roused the indignation of Mr. 

 Playfair, who exposed "the new-iprung zeal for orthodoxy" in n 

 satirical pamphlet published at Edinburgh in 1800, under tbe title of 

 a ' Letter to the Author of the Examination of Mr. Stewart's Short 

 Statement of Facts relative to the Election of Professor Leslie.' 



Hia intimacy with Dr. James Mutton led to his becoming a strenu- 

 ous supporter of tbe doctors geological theory, and to his writing 

 ' illustrations of the Huttonian Theory of the Earth,' Edin , 1802, 

 8vo (' Work*,' vol. I). Of tho necessity of more extensive observa- 

 tion Mr. Playfair was fully aware ; and, besides many journeys under- 

 taken for the purpose of examining the geological features of his own 

 country, immediately after the restoration of peace, in 1815, be set 

 out upon a geolo.ical tour through France, Switzerland, and Italy, in 

 arch of material for an enlarged edition of his ' Illustrations,' which 

 however other occupations prevented him from maturing for the press. 

 He died at Edinburgh on the 19th of July 1819. Francis Jeffrey, in 

 an elaborate notice of him, which appeared in tbe ' Annual Biography' 

 for 1820, says very truly, that "he poeMved in tbe highest degree 

 all the characteristics both of a fine and powerful understanding ; at 



once penetrating and vigilant, but more distinguished perhaps by the 

 caution and nuccets of its march than by tbe brilliancy or rapidity of 

 its movements :" . . . and that " as a teacher he took care to 

 imbue tbe minds of his pupils, from the very commencement of their 

 study, with that relish for the truths it disclosed, and that high sense 

 of tbe majesty with which they were inverted, that predominated in 

 bis own bosom . . . and formed them betimes to that clear, 

 masculine, and direct method of investigation by which, with the 

 least labour, tho greatest advance* might be accomplished." 



From the year 1804 he was a frequent contributor to the ' Edinburgh 

 Review,' and most of his articles in that periodical still possess con- 

 siderable value. They are 1, Review of Mudge'i ' Trigonometrical 

 Survey,' v., 1805; 2, Review of Mecbain and Delambre, 'Base du 

 Systcme'Metrique Decimate,' ix., 1807; 3, Review of Laplace, 'Trait<5 

 de Mechanique Celeste,' xi., 1808; 4, Review of ' Le Comptc rendu 

 par I'lnstitut de France, xv., 1 809 ; 5, Review of Lambton s ' Indian 

 Survey,' xxl, 1818; 6, Review of Laplace, ' Essai philosophique sur 

 Ics Probabilitos,' xxiii, 1814 ; 7, Review of Baron de Zach, Attrac- 

 tion des Montaigne*,' xxvi., 1816 ; 8, Review of ' Kater on the Pendu- 

 lum,' xxx., 1818. The whole of these are reprinted in tbe fourth 

 volume of the collected edition of his works, published at Edinburgh 

 in 1822, in 4 vols. 8vo, to which is prefixed a memoir of the author 

 by Dr. James O. Playfair. To the ' Encyclopaedia Britannica ' he 

 contributed the articles ' -iKpinus ' and ' Physical Astronomy,' and an 

 incomplete 'Dissertation on tho Progress of Mathematical and Physical 

 Science since the Revival of Letters in Europe* ('Works,' vul. ii). 

 The proofs of this were under revisal at the time of his death. His 

 contributions to the ' Transactions of the Edinburgh Royal Society ' 

 are: 1, 'On the Causes which affect the Accuracy of Barometrical 

 Measurement,' L, 1788 ('Works,' vol. iii); 2, 'Life of Matthew 

 Stewart,' i., 1788 ('Workii,' iv.) ; 8, 'Remarks on tho Astronomy of 

 the Brahmins,' ii., 1790 (' Works,' iii.); 4, 'On tho Origin and Inves- 

 tigation of Poriams,' iii., 1794 (' Works,' Hi.); 5, ' On the Trigonometry 

 of tho Brahmins,' iv., 1798 ('Works,' iii.) ; 6, ' Theorems relative to 

 the figure of tbe Earth,' v., 1805 ('Works,' iii.); 7, ' Biograpliic.il 

 Account of the late Dr. James Button,' v., 1805 ('Works,' iv.); 8, 

 ' On the Solids of greatest Attraction,' vi, 1S09 (' Works,' iii.) ; i', On 

 the Progress of Heat in Spherical Bodies,' vi., 1812 (' Works,' iii.) ; 

 10, ' Biographical Account of Dr. John Robison,' viiL, 1815 (' Works,' 

 iv.); 11, ' On the Naval Tactics of the late John Clerk, Esq.,'!*.. 

 (' Works,' iii). His separate works not already mentioned are : 1, 

 ' Elements of Geometry,' Edin. 1795, Svo ; it contains tbe first six 

 books of Euclid, the elements of plane and spherical trigonometry, and 

 a supplement on the geometry of solids and the quadrature of the 

 circle, and has passed through four editions since it ceased to be used 

 as a text book in the university of Edinburgh. 2, ' Outlines of 

 Natural Philosophy,' Edin., 1812 and 1816, 2 vols. Svo. This con- 

 tains the heads of lectures delivered by the author at tho university 

 of Edinburgh. Merely the enunciations of the several propositions 

 and the formula; as adapted to practical application arc given, but 

 reference is made to other works, where the demonstrations will I c 

 found. The first volume comprises statics, dynamics, hydrostatics, 

 hydraulics, and pneumatics ; the second refers wholly to astronomy ; 

 a tliird volume was contemplated to comprise optics, electricity, and 

 magnetism, but was never executed. 



* PLAYFAIR, LYON, distinguished as a chemist. He is the son of 

 Dr. George Playfair, and was born at Bengal, in tbo East lu 

 1819. Hia father's family resided at St Andrews, in Scotland, to the 

 university of which place he was sent to receive his early education. 

 Here he evinced an inclination for chemistry, which led his friends in 

 1834 to send him to Glasgow, where he studied chemistry under Pro- 

 fessor Graham, the present Matter of the Mint. In 1835 be went out 

 to India, and during his short stay found time to cultivate his favourite 

 science, and give to the world some chemical analyses. On returning 

 to England he again studied under bis old teacher, Professor Graham, 

 who was now professor of chemistry in University College, London. 

 The fame of Liebig however attracted him to Giesseu, where he com- 

 menced the study of organic chemistry in 1838. In Liebig's laboratory 

 he successfully cultivated original analysis, and was the discoverer of 

 several new compounds. He took the degree of Doctor .if 1'liilosophy 

 in the University of Giessen. On his return to England he made 

 himself known as the translator of Liebig's ' Reports on the Progress 

 of Organic Chemistry' to the British Association. [LiEBio.] His first 

 position in England was that of chemical director of tho large calico 

 works of the Messrs. Thompson at CUtheroe. In 1843 he accepted the 

 post of Professor of Chemistry at tbe Royal Institution of Manchester. 

 In this position ho became a successful popular teacher, and in con- 

 junction with Dr. Smith and Mr. Joule prosecuted many original 

 chemical researches. During this period he was placed on the com- 

 mission for investigating the state of health of the large towns of 

 England. He was a very active commissioner, and several of the reports 

 of tho Health of Towns Commission were drawn up by him. He was 

 subsequently appointed chemist to the Museum of Economic Geology, 

 then in Craig's-court. The laboratory of the present builiiiug in 

 Jermyn-street waa constructed under his direction. In conjunction 

 with Sir Henry de la IJtche ho investigated tbe combustible properties 

 of the various kinds of coal. Ho analysed tho qualities of the gas 

 given off by burning coals, and the result* of his labour* on these sub- 



