DOLOMIEU, DEODAT-GUY-SILVAIN. 



DOMAT, JEAN. 



622 



menced a series of experiments on the dispersion of light, and other 

 subjects connected with the improvement of optical instruments, and 

 especially of telescopes and microscopes, the results of which were 

 communicated to the Royal Society in a series of papers. Three of 

 them were printed in the 'Philosophical Transactions' for 1753, one 

 in 1754, and the last in 1758, the titles of which are given below. It 

 was about 1755 that he entered upon a systematic course of experi- 

 ments on dispersion, aud after, to use his own words, 'a resolute 

 perseverance' for more than a year and a half, he made the decisive 

 experiment which showed the error of Newton's conclusions on this 

 subject The memoir in which the series of investigations was 

 detailed appeared in the 'Philosophical Transactions,' and was the 

 last which he gave to the world. It was rewarded by the council of 

 the Royal Society with the Copley medal 



It was the lot of Dollond to undergo considerable annoyance on 

 account of the claims set up for this discovery in favour of others, 

 especially of Euler ; but there is not a shadow of a doubt of Dol- 

 lond's priority as well as originality, in this very important discovery, 

 left 011 the minds of the scientific world. The discrepancies which 

 followed the application of Newton's doctrine to the varied cases that 

 presented themselves in the course of different experiments might, in 

 minds, have created a suspicion of the accuracy of that 

 doctrine ; yet there does not appear to have been the least hesitation 

 among scientific men iu attributing these discrepancies to errors of 

 observation exclusively, and consequently not the least ground for 

 honestly attempting to deprive Dollond of the honour of the 

 discovery. 



In the beginning of the year 1761 Dollond was elected a Fellow of 

 the Royal Society, and appointed optician to the king. "He did not 

 long survive to enjoy the honour or advantages of his discoveries ; a 1 ! 

 on the 80th of September of that year, he was attacked by a fit of 

 apoplexy, brought on by a too close and long continued application to 

 a paper which he was studying. This attack immediately deprived 

 him of speech, and in a few hours of life itself. 



Besides his eldest son Peter, already mentioned (who survived him 

 till 1820, when he died age^ ninety), he left another son John, and 

 three daughter?. The two sons carried on the business jointly with 

 great reputation and success; and upon the death of the younger in 

 1804, Peter Dollond took into partnership a nephew, George Hugging, 

 who assumed the name of Dollond, and who continued the busi- 

 ness without diminution of the high character attached to the name 

 of Dollond, till his death in May 1832. Mr. George Dollond trans- 

 mitted the now famous business to a nephew of his, also named 

 George Huggins, and he in his turn obtained the royal permission to 

 assume the surname of Dollond instead of Huggins. 



The following U the list of John Dollond's published papers : 1, 

 'A Letter to Mr. James Short, F.R.S., concerning an Improvement 

 in Reflecting Telescopes;' ' Phil. Trans.,' 1753, p. 103. 2, 'Letter to 

 James Sho'rt, A.M., F.R.S., concerning a mistake in Mr. Euler's Theo- 

 rem for correcting the Aberration iu the Object Glasses of Refracting 

 Telescopes;' 'Phil. Trans.,' 1753, p. 287. 3, 'A Description of a 

 Contrivance for measuring Small Angles; ' ' Phil. Trans.,' 1753, p. 173. 

 4, ' An Explanation of an Instrument for measuring Small Angles ; ' 

 'Phil. Tran.,' 1754, p. 551. 5, 'An account of some Experiments 

 concerning the different Refrangibility of Light;' 'Phil. Trans.,' 175S, 

 p. 733. 



DOLOMIEU, DEODAT-GUY-SILVAIN TANCREDE GRATET 

 DE, was born at Grenoble on the 24th of June 1750. In early youth 

 he was admitted a member of the religious order of Malta, but in 

 consequence of a quarrel with one of his companions which ended in 

 a duel fatal to his adversary he received sentence of death, but after 

 imprisonment he was pardoned, and went to France. After somo 

 hesitation whether he should devote himself to classical literature or 

 to natural history, he decided in favour of the latter. While at Metz 

 with the regiment of carbineers, in which he had obtained a eomrniH.-iou, 

 he formed an acquaintance with the celebrated La Rochefoucault, which 

 ceased but with his existence. Dolomicu was soon afterwards elected 

 a corresponding member of the Academy of Sciences, and quitted the 

 military profession. 



At the age of twenty-six Dolomieu went to Sicily, and his first 

 labour was an examination of the environs and strata of yl'-tna. He 

 next visited Vesuvius, the Apennines, and the Alps, and in 1783 

 published an account of his visit to the Lipari Islands. Ho returned 

 to France at the commencement of the revolution, and early ranged 

 It on the popular side. He had however no public employment 

 until the third year of the republic, when he was iucluiled in the Ecole 

 <lu Mines, then <\<t.iMishcd ; and he was one of the original members 

 of the National Institute, founded about the same time. He was 

 indefatigable in the pursuit of geological and miueralogical science, and 

 in ICH.S Jian three years he published twenty-seven original memoirs, 

 among which were those on the nature of Leucite, Peridot, Anthracite, 

 Pyroxene, 4c. 



When lionaparte undertook the conquest of Egypt, Dolomieu accom- 

 pruiifiil the expedition. He visited Alexandria, the Delta, Cairo, the 

 I'yrmai'l", and a part of thn mountains which bound the valley of the 

 Nil 1 ); and he proposed also to explore the more interesting parts of 

 the country, but before h '<>uM carry bin plan into execution his 

 health became so deranged that he was compelled to return to Europe. 



On his passage home he was with his friend Cordier, the mineralogist, 

 and many others of Ids countrymen, made prisoner after being driven 

 into the Gulf of Tarentum. His companions were soon set at liberty, 

 but the remembrance of the disputes which had existed between him 

 and the members of the Order of Malta lei to his removal and sub- 

 sequent imprisonment at Messina, wbers he was confined in a dungeon 

 lighted only by one small opening, which, with barbarous precaution, 

 was closely shut every night. The heat, and the small quantity of 

 fresh air admitted by the window of his prison, compelled him to 

 spend nearly the whole of his time iu fanning himself with the few 

 tattered remnants of his clothes, iu order to increase the circulation of 

 the air. Great exertion and urgent demands were made by the 

 scientific men of various countries to obtain his enlargement; and 

 when, after the battle of Marengo, peace was made with Naples, the 

 first article of the treaty was a stipulation for the immediate release of 

 Dolomieu. On the death of Daubenton he was appointed professor 

 of mineralogy, and soon after his return to France he delivered a 

 course of lectures on the philosophy of mineralogy at the Museum of 

 Natural History. 



In a short time Dolomieu again quitted Paris, visited the Alps, and 

 returned to Lyon by Lucerne, the glaciers of Grindelwald and Geneva, 

 and thence to Chateauneuf, to visit his sister and his brother-in-law 

 De DriSe : here he was attacked by a disorder from the effects of which 

 he died, November 26, 1801. 



Dolomieu had projected two journeys for aiiling to hia vast storo 

 of geological knowledge the first througli Germany, and the second 

 through Norway, Denmark, and Sweden. He also proposed to publish 

 a work which ho had planned in his prison at Messina ; of this there 

 was printed a fragment on ' Mineral Species,' which is a monument 

 at once of his misfortunes and his genius, being written iu his dungeon 

 iu Sicily, on the margin of a few books, with a bono sharpened against 

 his prison-walls for a pen, and the black of his lamp-smoke mixed with 

 water for ink. In this work the author proposes that the integral 

 molecule shall be regarded as the principle by which the species is to 

 be determined, and that no other specific characters should be admitted 

 than those which result from the composition or form of the integral 

 molecule. It must however be admitted as an objection to this 

 proposal that the integral molecule is not always easily ascertained or 

 characterised. 



Soon after his death was published, 'Journal du Dernier Voyage du 

 Citoyen Dolomieu dans les Alpcs,' edited by Brunn-Nelgard, Paris, 8vo, 

 1802. M. Dolomieu's numerous ' Mdmoires ' are contained in the 

 'Mdmoires do 1'Institut,' ' Journal des Mines,' ' Journal de Physique.' 

 ' llec jeil de I'AcadcSmie des Sciences,' and the 'Voyage Pittoresquo (It- 

 Naples et de Sicile ;' ho also wrote several articles for the ' Dictionnaire 

 Mindralogique," and the ' Nouvello Encyclopedic." 



Dr. Thomson, in the 'Annals of Philosophy,' vol. xii., p. 166, has 

 drawn up an elaborate summary of the " results of Dolomieu's 

 observations and the bases of his geological systems." 



DOMAT, or DOUMAT, JEAN, a distinguished French civilian, was 

 born at Clermont in Auvergne, on the 30th of November 1623. He 

 connected himself with the brilliant circle of literary recluses at the 

 Port-Royal, among whom his reputation stood high both for j'u'in- 

 prudence and ethics. He was a very modest man, and comparatively 

 little is known of his personal history. For nearly thirty years he 

 presided, with marked credit, in the lower court of judicature at 

 Clermout. He was in the confidence of Pascal, attended him on his 

 death-bed, and was intrusted with many of his papers. His great 

 systematic work on the civil law appears to have long existed and 

 been perused by his friends in manuscript before it was published. 

 Rumours of tho valuo of the work coming to Louis XIV., Domat 

 received a pension, and took up his abode iu Paris, where ha received 

 encouragement from the kindness of D'Aguesseau, then conseiller 

 d'e"tat, through whose patronage many distinguished jurists appear 

 to have found their way to notice. Domat married Mademoiselle 

 Blondel, by whom he had thirteen children a circumstance deemed 

 worthy of particular commemoration in France. He died at Paris on 

 the 14th of March 1695, and, notwithstanding his pension aud his 

 office, is said to have euded his days in extreme poverty. In his works 

 he stands pre-eminently above all jurists of his age, and acquired a 

 reputation throughout Europe that has hardly beeu subsequently 

 reached by any of his countrymen. His work, 'Les Loix Civiles dana 

 leur (Ji-dre Nature], suivies du Droit Public,' appeared anonymously 

 in 16S9, aud is said to have been for some time attributed to Delauney, 

 professor of jurisprudence in tho University of Paris a statement 

 scarcely recoucilenble with tho alleged reputation of the work while 

 in manuscript. The author's method of dividing the subject is, by 

 first treating of the rules of law in general. This branch of the work 

 is almost of an ethical character. The principle of every law, as having 

 a foundation in utility or some other reason connected with morals or 

 religion, is the main feature of the work, aud iu this it adopts the 

 system which was afterwards more elaborately carried out and applied 

 to a larger number of subjects by Montesquieu. Tho substance of 

 the law is divided into private and public. The former class is sub- 

 divided into tho law of contracts aud the law of BucceeBJon* T!i > 

 public law is divided into government, official uud executorial nr: 

 incuts, crimes, aud procedure civil and criminal. There Imv 

 several editions of the work in French, generally iu two volumes, folio. 



