ROB 



excellent mathematician of the 17th century, was born at 

 Roberval, a feignory belonging to his family, in the diocefe 

 of Beauvais, in the year 1602. In the courfe ot his educa- 

 tion he difcovered a ftrong inclination towards the ftudy of 

 the mathematics, with which lie made himfelf very conver- 

 fant. When he was 30 years of age he obtained the pro- 

 fefforfhip of mathematics in the college of Gervais, at Paris ; 

 and afterwards he contefted, with other candidates, the fuc- 

 cefiion to the vacant chair of Ramus, which he gained by the 

 fuperiority of his powers in difputation. He fucceeded Marin 

 as mathematical profeffor at the college-royal, the duties of 

 which office he performed with high reputation fo long as In- 

 lived. He was chofen a member of the Royal Academy of 

 Sciences in 1666, and communicated to that body lomc cu- 

 rious experiments on the Torricellian vacuum, which he made 

 in the years 1647 and 1648. He invented two new kinds 

 of balances, one of which was adapted to the weighing of 

 air. Roberval died in 1675, at the age of 73. His chief 

 works are " A Treatife on Mechanics," inferted in Mer- 

 fenne's " Univerfal Harmony." A treatife " On the Mun- 

 dane Syftem," written in Latin, attributed to Ariftarchus of 

 Samos, but generally believed to be his own production. 

 Befides thefe he contributed feveral papers to the Memoirs 

 of the Academy of Sciences : fuch as " Experiments con- 

 cerning the PrefTure of the Air ;" " Obfervations on the 

 Compofition of Motion, and on the Tangents ot Curve 

 Lines ;" "The Geometrical Reiolution of Plane and Cubic 

 Equations ;" " A Treatife on Indivifibles ;" at the end of 

 which he has explained a new method for the transformation 

 of figures, to which Torricelli gave the name of " Rober- 

 vallian Lines." 



ROBERVALLIAN Lints, a name given to certain 

 lines, ufed for the transformation of figures : thus called 

 from their inventor M. de Roberval. 



Thefe lines bound fpaces infinitely extended in length, 

 which are neverthelefs equal to other (paces terminated on 

 all fides. 



The abbot Gallois, in the Memoirs of the Royal Aca- 

 demy, anno 1693, obferves, that the method of transforming 

 figures, explained at the latter end of M.de Roberval's 

 Treatife of Indivifibles, is the fame with that fince publifhed 

 by Mr. James Gregory, in his Univerfal Geometry, and 

 afterwards by Barrow, in his Lectiones Geometricse ; and 

 that, by a letter of Torricelli, it appear.^ that Roberval was 

 the inventor of this manner of transforming figures, by 

 means of certain lines, which Torricelli therefore called 

 Robervallian lints. 



He adds, that it is highly probable, that J. Gregory firft 

 learned the method in the journey he made to Padua in 

 1668 ; the method itfelf having been known in Italy from 

 the year 1646, though the book was not publiflicd till the 

 year 1692. 



This account Dr. David Gregory has endeavoured to 

 refute, in vindication of his brother. His anfwer is inferted 

 in the Phil. Tranf. an. 1694, and the abbot has rejoined 

 in the French Memoirs of the Academy. 



ROBESON, in Geography, a county of North Carolina, 

 ia Fayette diltrift, bounded S. by the itatc of South Caro- 

 lina. It contains 7528 inhabitants. The chief town is 

 Lamberton. — Alfo, a townfhip of Lancaller county, 

 Penniylvania ; containing 1807 inhabitants. 



ROBESPIERRE, Maximii.iam Isidork, in Biogra- 

 phy, was born at Arras in 1759. His father, a barrillcr, 

 having ruined himfelf by his prodigality, left France before 

 the revolution, eftablifhed a fchool at Cologne, where, how- 

 ever, he did not remain long, and he went from thence into 

 England, and afterward* to America. Uefcrtcd by his fa- 



Vot XXX. 



ROB 



ther, and his mother dying when he was only nine years old. 

 he was taken under the patronage of the bifhop of Arras, 

 M. de Conzie, who caufed him to be fent to the college of 

 Louis le Grand, where he was taken on the foundation. 

 From a very early age he was noticed for his love of inde- 

 pendence ; he was however timid, and in his temper gloomy 

 and unlociable. He was extremely afliduous in his ttudies, 

 and gave hopes of talent, that were not realized in after-life. 

 In 1775, when Lewis XVI. made his entry into Paris, he 

 was cholen by his fellow ftudents to prefent to that prince 

 the homage of their gratitude. Becoming a barrifter in the 

 council of Artois, he obtained a place in the academy of 

 Arras. In the year 1 789 he took an aftive part in all the 

 revolutionary meetings, and was appointed a deputy from 

 the province of Artois to the States-General. He manifefted 

 but little talent as an orator or legillator, but attached him- 

 ielf to Neckar, and then to Mirabeau, during the heights of 

 their popularity ; but when they became lefs carefTed by the 

 people, Robefpierre was the firft to notice the difference, 

 and delerted them for fome other leader. The firft. time 

 that he made himfelf at all remarked in the conftituent 

 afiembly, was on the 20th of July 1789, when he oppofed 

 the fcheme of martial law ; and from that period, fays his 

 biographer, " he endeavoured to legitimatize infurreftion." 

 By courting the people, and difplaying a determined hofti- 

 hty to the royal prerogatives, he laid the foundation for 

 future influence in the democratic party ; and it has been 

 confidered a very remarkable ciroumftance, in conneftion 

 with his future conduct, that the moft frequent topic of his 

 declamation was the injuftice of capital punifhment in any 

 cafe. 



After the difiblntion of the conftituent afiembly, followed 

 by the election of the legillative body, the members of 

 which being all new, Robefpierre' s chief theatre of aftion 

 was the Jacobin club, at which he was the principal fpeaker. 

 He alfo publifhed a weekly paper, entitled " Le Defenfeur 

 de la Confutation." He now took a decided part with the 

 republicans, though it does not appear that he was an aftor 

 in the infurreftion of the 10th of Auguft, or in the prifon- 

 maflacres of September. In the new afiembly, which met 

 in September 1792, he was returned a member for the city 

 of Paris, and he loon became the head of the party called 

 the Mountain, which was oppofed to the followers of Ballot, 

 who then poffefled the minifterial power. He was now 

 charged with the delire of making himfelf diftator, but his 

 party in the fenate was too powerful for his accuferto carry 

 the point, and the afiembly parted a decree to print and cir- 

 culate the fpeech which he made in jultification of himfelf. 

 By this he became ftill more popular, and his fubfequent ex- 

 ertions to bring the unfortunate king to trial, augmented his 

 influence with the democratic part of the nation. Soon after 

 the execution of Lewis, Robefpierre, aflifted by Danton and 

 Marat, gained a mo ft decided fupremacy in the national 

 convention, and the period commenced which has been em- 

 phatically, but juftly, denominated the reign of terror. The 

 Briflotines, to the number of twenty-one, were ace ufed, con- 

 demned, and guillotined. After them followed the queen, 

 the duke of Orleans, and other memb X8 oi the royal family. 

 The fcaffold daily ftreamed with the blood of nobles, priefts, 

 and all who by qhaxafter and condition could be fufpefted 

 of being attached to the ancient government. In fome of 

 the provinces, mailacrcs were perpetrated againll whole 

 orders of men, without diftindion : the levelling principle 

 was extended to all lupenorits oi feience and talent, audit 

 feemed Robeipierre's object to bring back an age of bar- 

 barifm. At length his own confederates, Danton, Def- 

 moulin;, Fabre d'Eglantine, .mJ others, were brought to the 

 3 A block. 



