DOLOMIEU  , D$ODAT

GUY SILVAIN TANCREDE GRATET DE (1750—1801), French geologist and mineralogist, was born at Dolomieu, near Tour-du-Pin,in the department of Isere in France, on the 24th of June 1750 . He was admitted in his infancy a member of the Order of Malta . In his nineteenth year he quarrelled with a knight of the galley on which he was serving, and in the duel that ensued killed him . He was condemned to death for his crime, but in consideration of his youth the grand master granted him a pardon, which, at the instance of Cardinal Torrigiani, was confirmed by Pope Clement XIII., and after nine months' imprisonment he was set at liberty . Throughout that period he had solaced himself with the study of the physical sciences, and during his subsequent residence at Metz he continued to devote himself to them . In 1775 he published his Recherches sur la pesanteur des corps d diferentes distances du centre de la terre, and two Italian translations of mineralogical treatises by A . F . Cronstedt (1702—1765) and T . O . Bergman (1735—1784) . These works gained for him the honour of election as a corresponding member of the Academie des Sciences at Paris . To obtain leisure to follow his favourite pursuits Dolomieu now threw up the commission which, since the age of fifteen, he had held in the carabineers, and in 1777 he accompanied the bailli (afterwards Cardinal L .

R . E.) de

Rohan to Portugal . In the following year he visited Spain, and in 178o and 1781 Sicily and the adjacent islands . Two months of the year 1782 were spent in examining the geological structure of the Pyrenees, and in 1783 the earth-quake of Calabria induced him to go to Italy . The scientific results of these excursions are given in his Voyage aux Iles de Lipari (1783); Memoire sur le tremblement de terre de la Calabre (1784); Memoire sur les 'Iles Ponces, et catalogue raisonne des produits de l'Etna (1788) and other works . In 1789 and 1790 he busied himself with an examination of the Alps, his observations on which form the subject of numerous memoirs published in the Journal de physique . The mineral dolomite, which was named after him, was described by Dolomieu in 1791 . He returned to France in that year, bringing with him rich collections of minerals . On the 14th of September 1792 the duc de la Rochefoucauld, with whom he had been for twenty years on terms of the closest intimacy, was assassinated at Forges, and Dolomieu retired with the widow and daughter of the duke to their estate of Roche Guyon, where he wrote several important scientific papers . The events ofthe 9th Thermidor (July 27, 1794) having restored the country to some tranquillity, Dolomieu recommenced his geological tours, and visited various parts of France with which he had been previously unacquainted . He was in 1796 appointed engineer and professor at the school of mines, and was chosen a member of the Institute at the time of its formation . At the end of 1797 he joined the scientific staff which in 1798 accompanied Bonaparte's expedition to Egypt .

He had proceeded up the

Nile as far asCairo when ill-health made his return toEurope necessary, and on the 7th of March 1799 he set sail from Alexandria . His ship proving unseaworthy put into Taranto, and as Naples was then at war with France, all the French passengers were made prisoners . On the 22nd of May they were carried by ship to Messina, whence, with the exception of Dolomieu, they embarked for the coast of France . Dolomieu had been an object of the hatred of the Neapolitan court since 1783, when he revealed to the grand master of his order its designs against Malta, and the calumnies of his enemies' on that island served now as a pretext for his detention . He was confined in a pestilential dungeon, where, clothed in rags, and having nothing but a little straw fQr a bed, he languished during twenty-one months . Dolomieu, however, did not abandon himself to despair . Deprived of writing materials, he made a piece of wood his pen, and with the smoke of his lamp for ink he wrote upon the margins of a Bible, the only book he still possessed, his treatise Sur la philosophie mineralogique et sur l'espece minerale (18o,) . Friends entreated, but in vain, for his liberty; it was with difficulty that they succeeded in furnishing him with a little assistance, and it was only by virtue of a special clause in the treaty between France and Naples that, on the 15th of March 18o1, he was released . On his arrival in France he commenced the duties of the chair of mineralogy at the museum 392 in Munich, on the 14th of January ago, at the age of ninety-one . Even in articulo mortis he refused to receive the sacraments from the parish priest at the cost of submission, but the last offices were performed by his friend Professor Friedrich . In addition to the works referred to in the foregoing sketch, we may mention The Eucharist in the First Three Centuries Mainz, 1826) ; a Church History (1836, Eng. trans . 1840); Hippolytus and Callistus (1854, Eng. trans., 1876) ; First Age of Christianity (186o) ; Lectures on the Reunion of the Churches; The Vatican Decrees; Studies in European History (tr .

M . Warre, 189o) ;

Miscellaneous Addresses (tr . M . Warre, 1894) . See Life by J . Friedrich (3 vols . 1899—1901); obituary notice in The Times, rah January 189o; L. von Kobell, 'Conversations of Dr Dellinger (tr. by K . Gould, 1892) . (J . J .