PRODICUS. 



FRONT, GASPARD-CLAIR-FRANCOIS DE. 



was. In this passage Sempronius Proculus sends greeting to his 

 grandson, and asks him his opinion about a legacy. "Proculus 

 respondit," Proculus gave his opiuion, and therefore the grandson and 

 Proculus are the same person ; and, as Zimmern remarks, Proculus 

 the jurist might be the son of the daughter of Sempronius Proculus 

 the grandfather, in which case his name would not be Sempronius. 

 It has been conjectured that Proculus the jurist is the Liciniua Procu- 

 lus whom Otho made Pnefectus pnetorio (Tacitus, ' Hist.,' i. 46, 82, 

 67 ; ii. 39, 40, 44, 60). Proculus is often cited in the 'Digest,' and he 

 is specially mentioned in a Rescript of the Divi Fratres as an eminent 

 authority (' Dig.,' 37, tit. 14, s. 17). There are thirty-seven excerpts 

 in the ' Digest ' from a work of Proculus, entitled 'Epistolae,' of which 

 there were at least eleven books ('Dig.,' 18, tit. 1, s. 69), though the 

 Florentine Index mentions only eight. One of the excerpts (' Dig.,' 

 33, tit. 6, s. 1 6) has the title ' Proculus, libro iii. ex Posterioribus 

 Labeonis,' which appears to be a separate work or commentary on the 

 ' Posteriora ' of Labeo. But as Javolenus wrote on the ' Posterior* ' of 

 Labeo (' Dig.,' 33, tit. 7, B. 4), it is conjectured that the title of s. 16 

 (' Dig.,' 33, tit. 6) should be 'Javolenus.' 



PKO'DICUS, a native of Cos, or, aa some think, of Chios, flourished 

 B.C. 435. He was a disciple of Protagoras, became a celebrated 

 Sophist, and had among his followers Socrates, Euripides, Isocrates, 

 and Xenophon. Prodicus travelled through Greece from town to 

 town, to deliver his lectures, for which he demanded payment of his 

 hearer?, sometimes to an extravagant amount. Several ancient writers 

 refer to these lectures, or harangues, as worthy of a philosopher. Pro- 

 flicus however is reported to have been put to death by the Athenians, 

 because they thought that he corrupted the youth by his teaching ; 

 and it is further remarkable that he is numbered among the atheists 

 by Cicero. (' De Nat. Deorum,' i 42.) None of the writings of Pro- 

 dicus are extant except a beautiful episode preserved by Xenophon 

 ('Mem.,' ii. 1), usually called 'The Choice of Hercules.' This has 

 been paraphrased in English verse by Sheustone and by Bishop Lowth, 

 and there is a prose translation in the ' Tattler.' Three others of this 

 name are noticed by Fabricius, but very little concerning them is 

 known. (Fabricius, Jiibliotheca Grceca.) 



PROK.OPHIEV, IVAN PKOKOPHIEVITCH, an eminent Russian 

 artist, was born at St. Petersburg, on the 25th of January 1758. At 

 the age of twelve he began to study sculpture under Gilet, one of the 

 professors at the Academy of Fine Arts, and during the eight following 

 years obtained medals and prizes for various bas-reliefs, to which 

 branch of the art he afterwards more especially applied himself. 

 Having gone through the course of studies at the academy, he was 

 sent, at its expense, in September 1779, to perfect himself under 

 Julien at Paris, where, in the following year, he executed a bust in 

 marble of Prince Gagarin, and a relief in terra-cotta representing 

 Motes, which last, and a similar one of Morpheus, are in the Academy 

 at St. Petersburg. Having passed a few months at Berlin and Stettin, 

 on his way home, he returned to St. Petersburg in the summer of 

 1784 ; and from that time till within a few years preceding his death 

 he continued to practise his art most industriously. His productions 

 are so numerous that even a mere list of them would extend to a 

 considerable length; but the majority were certainly not of the kind 

 to excite much public attention, aa they consisted chiefly of bas-reliefs, 

 medallions, and works of that class, on a comparatively small scale, 

 and executed for private individuals. Many of them besides were 

 only in terra-cotta. Taken generally however they are allowed to dis- 

 play considerable powers of invention and ability in composition." In 

 tlie Imperial Library at St. Petersburg there are sixteen small carya- 

 tides and twenty-eiuht bas-reliefs by him. His last work was a bust 

 of the Polish poet Treinbecki ; soon after the completion of it he was 

 attacked by a complaint that deprived him of the use of his right 

 hand, at least rendered him incapable of employing it either in model- 

 ling or designing. He died at St. Petersburg, on the 10th of February 

 1828, in his seven ty-firnt year. 



The earlier productions of this artist have, with much beauty, 

 somewhat also of the French mannerism of that day in sculpture, 

 caught, no doubt, from bin instructor Julien ; but he afterwards com- 

 pletely corrected that fault, and his later works display a more 

 classical style. 



PROMO'TUS, JELIUS, an Alexandrian physician, whose data is not 

 exactly known. Villoison ('Anecd. Gr.,' torn, ii., p. 179, not. 1) says 

 that he lived after the time of Pompey the Great; but Passeviu 

 ('Bibl. Select.,' p. 17), and Ant. Bongiovanui, in his letter to Giov. 

 della Bona (lo. a Bona, 'Tract de Scorbuto,' 4to, Veronse, 1781), 

 consider him to be much more ancient. He is probably the person 

 mentioned by Galen ('De Compos. Medicam. sec. Loca,' lib. iv., cap. 6), 

 and he is the author of several Greek medical works, which are still in 

 manuscript in different European libraries. The prologue to one of 

 these, entitled $vva/ifpbi>, i.e., ' Congeries Medicaminum secundum 

 Loo,' together with some extracts from it, is to be found in Bona's 

 treatise quoted above, and ia reprinted by Kiihn, in his ' Additam. ad 

 Klench. Modicor. Vet. a lo. A. Fabricio exhibit,' 4to, Lips., 1826. The 

 extracts consist of recipes for different diseases. The work exists in 

 manuscript in St. Mark's Library at Venice, No. ccxcv., -Ho. (Morell, 

 ' Iliiil. Iu.it.. cum Grtec. turn Latin.,' i. 170.) Fabricius mentions 

 another of his works, entitled iWpiicA, QvaiKa, xdl ivrmaffrirtKii, which 

 xista in manuscript at Leydeu among the books belonging to Voss. 



Schneider says (' Prsefat. in Nicand. Alexipharrn.,' p. 19) that, judging 

 from an extract sent him by Ruhnken, the work is so full of absurdities 

 as not to deserve to be published. Another of his works, entitled irepl 

 io@o\n>v Kal BrjATjTjjpiW $ap/idKtav, is to be found in the libraries at 

 Rome and at Paris. Mercuriali has inserted a few fragments in his 

 ' Varise Lectiones ' (lib. iii., cap. 4), and several times quotes it in his 

 work ' De Venenis, et Morbis Veneuosis,' lib. i,, cap. 16 ; lib. ii., cap. 2), 

 from which it appears (lib. iii., cap. 4) that he agreed with ^Elian (' De 

 Nat. Aniin.,' lib. vi., cap. 20), Apollodorus (ap. Plin., ' Hist. Nat.,' 

 lib. xi., cap. 30), and Nicander ('Ther.,' v. 769, &c.), in dividing 

 scorpions into nine species. 



PRONY, GASPARD-CLAIR-FRANCOIS-MARIE-RICHE DE, was 

 born at Chamelet, in the department of the Rhone, July 22, 1755. 

 His father was a member of the ' parliament,' 1 or chief civil court of 

 the ancient principality of Dombes ; and at the College of Thoisaey 

 in that principality Prony received his education xintil 1776, when he 

 entered the ' Ecole des Fonts et Chausse'es.' Here his assiduity was 

 such as to lead Perronnet to foretel that he would one day occupy his 

 onn position, that of head of the establishment. He first became 

 known as an author by an essay on the ' Thrust of Arches,' published 

 in 1783, about which time he began to be employed under Perronnet 

 upon several public works, among which may be mentioned the 

 restoration of the port of Dunkirk (1783), and the erection of the 

 bridge of Louis XVI. (1787-90), of which last the engineering plan is 

 said to have been drawn up and its execution superintended by Prony. 



In 1790 he published the first volume of his ' Hydraulic Architec- 

 ture.' The second appeared in 1796. Prior to this, the only work 

 of the kind accessible to the engineer was the standard work beariug 

 the same title, by Belidor, published in 1737-53 ; so that, as Delambre 

 observes, the progress which the theory of mechanics had made in the 

 hands of Euler, D'Alembert, Lagrange, and Laplace, had lain without 

 real application to the arts of construction. Prony 's work is perhaps 

 the first of an elementary character in which the directions of forces, 

 and the systems on which they act, are referred to rectangular co- 

 ordinate axes. It contains a clear exposition of the steam-engine, at a 

 time when the steam-engine was scarcely known on that side of the 

 channel ; but his empirical formulae for determining the elasticity of 

 steam, the investigation of which occupies a considerable portion of 

 the second volume, have been entirely superseded by more recent 

 researches. His method of determining the diameter of a steam-cylinder 

 Tredgold designates aa " little better than telling the artist to guess at 

 it, and correct hia guesa by an intricate formula." The same author 

 remarka that the labours of Prony in this department " afford the 

 strongest evidence that mere mathematical talent is not sufficient for 

 the promotion of mechanical science, otherwise the principle of the 

 steam-engine would not have remained to be investigated." (Tredgold 

 ' On the Steam-Engiue,' 4to, i., p. 33, Lond., 1838.) 



Among other scientific projects of the. French revolutionary govern- 

 ment at this period was tbat, suggested by Carnot and others, of 

 computing a set of mathematical tables, by which it was supposed two 

 objects would be attained the application of the decimal division of 

 moneys, weights, and measures, then recently introduced, would be 

 facilitated ; and the world astonished by the " most vast and imposing 

 monument of calculation which had ever been executed or even con- 

 ceived." The direction of this laborious undertaking was confided to 

 Prony in 1792 (year ii.), and with him were associated three or four 

 of the principal mathematicians of Paris, including Legendre. It was 

 however easy to foresee that their joint efforts, and the exclusive 

 devotion of the rest of their lives, would alone be inadequate to the 

 completion of the task they had undertaken. Occupied with this 

 discouraging reflection, Prony opened by accident a volume of Adam 

 Smith's ' Wealth of Nations,' at a part where the author is instancing 

 the manufacture of needles in illustration of the principle of the 

 division of labour. " Why," thought Prony, " should not the same 

 principle be applicable, and with equal advantage, in the manufacture 

 of logarithms ! " Pondering on the practicability of this, he retired 

 into the country, and in a few days returned with hia plan of operations 

 fully digested. He divided his assistants into three sections ; the first, 

 of which Legendre waa the president, was occupied in selecting from 

 "amongst the various analytical expressions which could be found for 

 the same function, that which was most readily adapted to simple 

 numerical calculation, by many individuals employed at the same 

 time." (Babbage, 'Economy of Manufactures,' p. 191.) These expres- 

 sions included several very elegant formulae investigated by Legeudre, 

 for determining directly the successive differences of the sines. The 

 second section " consisted of seven or eight persons of considerable 

 acquaintance with mathematics ; and their duty was to convert into 

 numbers the formulie put into their hands by the first section, an 

 operation of great labour ; and then to deliver out these formulae to 

 tlie members of the third section, and receive from them the finished 



calculations The third section, which consisted of from, sixty 



to eighty members, received certain numbers from the second section, 

 and using nothing more than simple addition and subtraction, they 

 returned to that section the tables in a finished state." (Babbage, 

 pp. 191, 192.) The whole of the calculations, which to secure greater 

 accuracy were performed in duplicate, and the two manuscripts sub- 

 sequently collated with care, were completed in the short space of two 

 yeara. They occupy seventeen " enormous' " folios, and consist of 



