737 



STOKES, GEORGE GABRIEL. 



STOLBERG, LEOPOLD FRIEDRICH. 



733 



fessor of mathematics in the university of tbat city; and, according to 

 Melcbior Adam, ho died of a contagious malady at Blaubeuren, 

 February 16, in the following year, being seventy-nine years of age. 



According to the practice of astronomers in that age, Stoffler spent 

 much of his time in the computation of ephemerides, and he appears 

 to have been first brought into notice by continuing the series which 

 Miiller (Reiomontanus) had commenced. He constructed an astro- 

 labe, which was intended to be used as an instrument for making 

 celestial observations, and on the plane of which were projected the 

 circles of the sphere: an account of the astrolabe was given by him in 

 a tract which was published at Tubingen in 1513 ; and in the same 

 tract there is given an account of an instrument for determining the 

 hour of the day by an observed altitude of the sun. 



Stonier employed himself on the subject of reforming the Julian 

 Calendar, and it is stated that he was the first who proposed to 

 rectify the error of that calendar by the omission of ten days in one 

 year, in order to make the succeeding days of the year correspond, as 

 at first, to the place of the suu in the ecliptic. It is said also that 

 Stoiilor offered his project to the Lateran council, and that it was not 

 accepted. Besides the ephemerides, and the above-mentioned tract 

 on the use of the astrolabe, Stoffler published astronomical tables 

 (Tubingen, 1500) ; a tract on the calendar (Oppenheim, 1518) ; and a 

 commentary on the Sphere of Proclus (Tubingen, 1531). 



* STOKES, GEORGE GABRIEL, M.A., D.C.L., F.R.S., who has 

 taken a very high rank among mathematicians and physicists of the 

 age, is of Irish origin, but was educated at the school of Christ's 

 Hospital, London, whence he was sent to Pembroke College, Cam- 

 bridge, where, as senior wrangler, he took the degree of B.A. in 1841, 

 and became a fellow of his college. He succeeded Dr. King as Lucasian 

 Professor of Mathematics in the University in the year 1849. 



On the 5th of June 1851, he became a Fellow of the Royal Society, 

 and received the Rumford Medal by an award of the Council of that 

 body in the following year, for his capital "discovery of the change in 

 the refrangibility of light." The researches of which this discovery 

 was the principal, though by no means the only result, originated in a 

 consideration by Professor Stokes of the very remarkable phenomenon 

 discovered by Sir Johu Herschel in a solution of sulphate of quinine, 

 which, though it appears to be perfectly transparent and colourless 

 like water, when viewed by transmitted light, exhibits nevertheless, 

 in certain aspects, and under certain incidences of the light, a beautiful 

 celestial blue colour. This had been shown by Sir David Brewster to 

 be a particular case of the general phenomenon of the chromatic dis- 

 persion of light within the substance of transparent bodies; whether 

 solid or liquid. But Professor Stokes determined that in the phe- 

 nomenon of internal dispersion so called the refrangibility of light is 

 changed, incident light of definite refrangibility giving rise to dispersed 

 light of various retrangibilities ; also that the colour of light is in 

 general changed by internal dispersion, the new colour always 

 corresponding to the new refrangibility ; and it being a matter of 

 perfect indifference whether the incident rays belong to the visible or 

 invisible part of the spectrum. And further, that the phenomena of 

 internal dispersion are perfectly conformable to the supposition that 

 the production of light, of chemical changes (attributed to a special 

 radiation termed actinic), and of phosphorescence (when excited by 

 the previous action of light,) are merely different effects of the same 

 cause. The experiments and inductions on which these conclusions 

 are founded are detailed in a paper in the ' Philosophical Transactions' 

 for 1852, of which it occupies 100 pages. An abstract will be found 

 in the 'Proceedings of the Royal Society,' vol. vi., p. 195, and in the 

 'Philosophical Magazine' for November 1852. The subject is con- 

 tinued in a shorter memoir in the 'Philosophical Transactions' for the 

 following year. Having in his first paper suggested the term 

 fluorescence (from fluor-spar, which exhibits the same phenomenon), 

 to denote the general appearance of a solution of sulphate of quinine, 

 as already described, and of similar media, the author now substitutes 

 that term, a single word not implying the adoption of any theory, for 

 that of internal dispersion, which ho shows to be inconvenient, even 

 if not untrue. 



At the anniversary meeting of the Royal Society in 1854, Professor 

 Stokes was elected, one of the two secretaries, to which office he has 

 been annually re-elected, and which he now holds (June 1857). 



Professor Stokes has instituted a series of experiments for the pur- 

 pose of determining the index of friction in different gases, which ar3 

 in progress, under his direction, at the Physical Observatory of the 

 British Association for the Advancement of Science at Kew, near 

 London. To defray the expenses of these experiments 175. was 

 appropriated in 1851 from the annual grant of IQOQl. to the Royal 

 Society by the government, to be employed in aiding the promotion 

 of science in the United Kingdom. He is the author of papers on 

 various subjects of mathematical physics in the ' Transactions of the 

 Cambridge Philosophical Society/ and in the third and fourth series 

 of the 'Philosophical Magazine; ' in vols. xxi. and xxii. of the third, 

 for the years 1842 and 1843, he discusses the analytical condition of 

 the rectilinear motion of fluids, with his colleague Professor Challis, 

 with whom he has in the same work discussed various other subjects. 

 In recent volumes will be found supplementary papers on the change 

 of the refrangibility of light and on fluorescence. 



It is important to notice here the remarkable view in fact, a dis- 

 Bioct, DIV. VOL. v. 



covery in itself which the theory of transversal vibrations has led 

 Professor Stokes to take, of what it is not incorrect to term, in one 

 respect, the physical nature of the luminiferous ether. While con- 

 ceiving it to be a fluid, as regards the motion of the earth and planets 

 through it, he finds that it must be regarded as an elastic solid in 

 treating of the vibrations of light. 'This conclusion is one of the 

 highest importance in connection with the philosophy of the nature of 

 matter, and the relations to space and to each other of different orders 

 of matter. We may hope, from the sagacity of the mind which has 

 arrived at it, much further progress in the same direction. Nor is the 

 fact that it is an independent re-discovery of a result long previously 

 attained by Young [YOUNG, THOMAS] any diminution of the merit of 

 its second discoverer. 



In his own University Professor Stokes gives annually a course of 

 lectures on the sciences of Hydrostatics, Mechanics, and Optics, which 

 is both theoretical and practical, and has particular reference to the 

 physical theory of light. By the admirable provision of the late Sir 

 Henry de la Beche, he has for several years past delivered lectures on 

 general physics, elementary and practical, to the students of the 

 Metropolitan School of Science applied to Mining and the Arts, at the 

 Museum of Practical Geology in London. 



STOLBERG, CHRISTIAN, COUNT, was the son of Count Christian 

 Gunther, a branch of the house of Stolberg-Stolberg, one of the most 

 ancient families in Germany, but who had accepted an office in the 

 household of Sophia Magdalena, the widow of Christian VI., king of 

 Denmark. Christian was born in Hamburg on October 15, 1748, and 

 was educated at the University of Gottingen, where, with his brother, 

 he soon distinguished himself by his love of literature, and by his 

 poetical talents. His works were published in connection with those 

 of his brother, and may be best mentioned with them, but we may 

 say here that in style he was a follower of Klopstock, and an admirer 

 and imitator of the classics. He was the author of ' Belsazer,' and 

 ' Otanes,' dramas in blank verse with lyrical unrhymed choruses ; a 

 translation of Sophocles ; and ' Gedichte aus dem Griechischen ' 

 ('Poems from the Greek'). The dramas have no great merit, and 

 were not adapted for theatrical representation. His reputation rests 

 on his miscellaneous poems, which contain interesting pictures of 

 domestic life and manners, and a pleasing expression of tender feelings, 

 which is peculiarly shown in those poems written on his brother's 

 death. After filling a few unimportant public offices he retired, on 

 his marriage in 1777 to the Countess of Reventlow, to his estate of 

 Windebye, near Eckernforde in Schleswig, and died on the 18th of 

 January 1821. 



STOLBERG, LEOPOLD FRIEDRICH, the brother of the preceding, 

 was born in November 7, 1750, at Bramstedt in Holstein. He pro- 

 secuted his studies with his elder brother, and like him became early 

 associated with the band of poets, Burger, Voss, and Holty, then 

 flourishing. Like his brother, he was an ardent admirer of the Greek 

 poets, and his first literary production was a translation of the Iliad, 

 which, though not rendered with scrupulous accuracy, reproduces 

 much of the fire and vigour of the original. He then with his brother 

 made a tour in Switzerland, a part of which was performed on foot in 

 company with Gothe and Lavater, and having visited Milan, Piedmont, 

 and Savoy, they returned to Copenhagen. In 1777, soon after their 

 return, the prince-bishop of Liibeck constituted Friedrich his minister 

 plenipotentiary at the Danish court, and the marriage of Christian in the 

 same year having separated the brothers for a time, Friedrich employed 

 himself on his translations of four of the dramas of ^Eschylus, which 

 contain the same defects and the same merits as his translation of the 

 Iliad. He also composed his dramas of ' Theseus ' and ' Der Siiug- 

 ling,' both formed upon classical models ; the latter containing some 

 vigorous passages expressive of a mother's grief for the loss of an 

 infant. In 1782 he married Agnes von Witzleben, a lady whom he had 

 celebrated in some of his poeins, and whose death in 1788 he comme- 

 morated in others. During their union, in 1785, he was entrusted 

 with an important mission from the court of Denmark to that of 

 Russia, which having fulfilled, he retired to Neuenburg, in Prussia, 

 where he wrote ' Der Island,' a novel as it is called, but of which only 

 a slight fiction of plot is used to introduce his own and his brother's 

 family with a few young friends, and the rest is entirely dialogue on 

 all sorts of subjects, containing many sound observations on morals 

 and manners, vivid recommendations of religion and virtue, pleasing 

 descriptions of scenery occasionally, and literary judgments on various 

 authors. Among these the admiration of the Greek authors is warmly 

 expressed, and to Ossian, whom he subsequently translated, is assigned 

 a very high rank. On the death of his wife Friedrich went to reside 

 with his brother in Holstein, and in the spring of 1789 he was again 

 selected as minister from Denmark, then menaced by an invasion from 

 Prussia, to the court of Berlin to divert the impending storm. He 

 was successful, and he continued to reside at Berlin, where in 1790 he 

 married the Countess Sophie von Redern, with whom he set out on an 

 extensive tour, comprising a considerable part of Germany, Switzer- 

 land, and Italy, including Sicily, an account of which was published 

 in 1794 under the title of 'Reise durch Deutschland, die Schweiz, 

 Italien, und Sicilien,' in 4 v.olumes. It contains some well-painted 

 descriptions, and much poetical enthusiasm, but is extremely discursive. 

 In it are inserted his poetical epistles to Ebert which he denominated 

 ' Hesperides.' After an absence of eighteen months, he returned, and 



3s 



