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HKLMONT, JOHN T BAPTIST . 



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IIKLIOGABALUS. [BbUUBAin.1 



H KI.L, M A X I M I LI AN. * diitinguiabed astronomer and member of 

 the orterof JuiU, wu born May 15, 1780. atSehemnitz in Hungary, 

 and muiteted, at an early age, a decided taste for tho study of natural 

 philoeopby and astronomy. At twenty-are year* of age he was 

 employed aa an aatistant in an observatory belonging to the Jesuit* 

 at Vienna, and be was at (be same time keeper of tho museum of 

 experimental philosophy which bad just then been formed in that 

 city. In 1746 be was made rector of an academy at Leutaohau in 

 Hungary ; but this post he held only one year, when he returned to 

 Vienna. Here he completed his theological studies, and received a 

 small number of pupils, whom he instructed in mathematics. He 

 took orders in 1751, and after throe years obtained the rank of 

 doctor, with an appointment to the professorship of mathematics at 

 Clausenburg in Transylvania. Having continued in this situation 

 four yrars, he again returned to Vienna, where he was established in 

 an observatory which bad been built in conformity to his own direc- 

 tions ; and be held the appointment during the remainder of his life. 

 Besides the duty of making celestial observations, he was charged 

 with that of giving lessons in mechanics ; as, in England, about eighty 

 yean earlier, the first astronomer royal was required to teach the use 

 of nautical instruments to two boys from Christ's Hospital : the 

 German astronomer however gave the lesions only during one year, 

 his time afterwards being fully occupkd in performing services more 

 important to science. 



Through the mediation of Count Bachoff, who was sent from Copen- 

 hagen for the purpose of making the proposal, he accepted an invita- 

 tion from the court of Denmark to undertake a journey to Wardhuys 

 in Lapland, in order to observe there the transit of Venus over the 

 eun's disc. Accordingly he set out from Vienna in 1768; and, after 

 staying a short time at Copenhagen, he proceeded to the place of his 

 destination : he was absent about two years and a half on that 

 uiisrion, when having fully succeeded in its object, he returned to 

 Vienna. Besides observing the transit, Holl took advantage of hia 

 residence in Lapland to study the geography, the natural history, and 

 the climate of die country ; the history, language and religion of the 

 people, with the state of tho arts among them : he made also nume- 

 rous observations on terrestrial magnetism, on the phenomena of the 

 tides and winds, and on the variations of the barometrical column ; 

 and be measured the heights of the principal mountains. After his 

 return he prepared a work containing a full account of his researches, 

 which was to have been published in three volumes, 4 to, but it never 

 appeared. 



Hell was very fortunate in the sky being favourable, on the day 

 (June 3, 1769) that the transit took place, so that he was enabled to 

 observe the interior contact at the commencement, and both the 

 interior and exterior contacts at the termination of the phenomenon ; 

 and it is a proof of the accuracy of his observations that the value of 

 the sun's parallax, which he deduced by comparing them with the 

 corresponding observations at certain other places, agreed, within one- 

 fifth of a second, with the value afterwards determined from compa- 

 risons with all the best observations which were made. 



On accepting the engagement, Hell was enjoined by the Danish 

 ministry to abstain from publishing any account of his observations 

 till his return to Copenhagen, and till he had made all the requisite 

 computations. The delay which, in consequence of this injunction, 

 took place in makiag Hell's observations public, gave otfeuco to 

 Lalande, who had, by letters addressed to the different governments 

 of Europe, greatly promoted the measure of observing tho phenome- 

 non at different places on the earth's surface ; the two astronomers 

 were however soon reconciled, and they continued to correspond with 

 each other as before. Hell drew up a memoir relating to the transit, 

 which was read before the Academy of Science? of Copenhagen, 

 November 24, 1769. 



The principal work published by this astronomer wag a scries of 

 Ephemerides in thirty-five volumes, 8vo, the collection being entitled 

 ' Kpheinoridea Anni 1757 - 1791 ad Meridianum Vindoboneusem 

 Calculi* definite.' With the exception of two volumes, these contain 

 appendixes on astronomical subjects by himself or other scion ti lie men, 

 chiefly by I'ilgram and Trieanecker; the former of whom edited the 

 work during the absence of Hell in Lapland. The rest of his publica- 

 tions on astronomical subjects are as follow : ' Tabula; Solares Nicol. 

 Ludov. do la Caille cum Supplemento Reliquarum Tabularum,' 1763 ; 

 ' Tabulaj Lururca Tub. Mayer cum Supplemento, etc.,' 1763 ; ' Do 

 Satellite Veneris,' 1765; 'De Transitu Vencris ante Discum Soils die 

 3Jun., 17t>9, Wardochusii observato,' 1770; 'De Parallaxi Solis ex 

 Obeenrationibus Transitus Venerii, anni 1769,' 1773; and 'Methodus 

 Astronomica sine Usu Quadrantis, etc.,' 1775. He also edited a col- 

 lection, which had been made' by Hallersteiu, of the astronomical 

 observations made by the Jeiuits at I'ekin from 1717 to 1752; this 

 wu published at Vienna, in 2 vols. 4to, iu 1768. 



Besides these works he published ' Klemcnta Algebra) J. Crivellii,' 

 f^vo, 1745; 'Adjumentum Mcmorico Manualo Chronologico-Genealogico- 

 Hintoricum,' Iflino, 1750; 'Klementa Arithmetics! Numeric;*: ct Lite- 

 ralis,' 8vo, 1763 ; also a tract on tho true magnitudes of the aun and 

 moon when seen by the naked oje, 1775 ; and one on a ' New Theory 

 of the Aurora Borealis,' 1776. 



All his works were published at Vienna ; and ho died in that city, 



April 14, 1782, being seventy-two years of age, A brother of Hell 

 was a distinguished mechanician at SchemniU, and the inventor of a 

 sort of siphon for draining mines : this is described in the ' Mduioires 

 de 1' Academic des Sciences de Paris ' for the year 1760. 



(Jlioyrajihie IfnivertelU; Delambre, llttt. de fAttronomie an Die- 

 huilifme SMe.) 



HELLA'NICUS, one of tho early Greek prose writers, was bora at 

 Mitylene in the island of Lesbos, ii.c. 49$ (' QelL,' xv. 23). According 

 to Lucian (' Macrob.,' c. 22) he lived to the age of eighty-five. Suidas 

 says that he lived at the court of Amyntas, king of Macedon, together 

 with Herodotus ; but this statement is inaccurate, since there was no 

 king of Macedon of the name of Amyntas during the lives of Hella- 

 nicus or Herodotus. 



He wrote several works, which are frequently quoted by ancient 

 writen ; of which the most important appear to have been, a 

 ' History of Argoa,' arranged in chronological order, according to the 

 successive priestesses of the temple of Hera in that city ; a ' History 

 of Attica, Cyprus, yEolia, and Lesbos;' an account of Phoenicia, 

 Persia, Scythia, and oth-r Kaatern nations, and some geographical 

 pieces. Hellanicua is mentioned by Thucydides (i. 97). 



The fragments which remain of the writings of Hellanicua were 

 published by Sturz, 8vo, Leip., 1787 ; 2nd edition, 182*3 ; and iu the 

 ' Museum Critioum,' voL ii., pp. 90-107, Camb., 1826. 



H ELMERS, JAN FREDliRIK, a popular Dutch poet, one of 

 whose works is still frequently reprinted and much read in Holland. 

 He was born at Amsterdam in 1767, was educated for commerce, but 

 after the success of an ' Ode to Night' and of a poem in three cantos 

 entitled ' Socrates,' gave himself up to literature, and published his 

 principal poem, ' De Hollandsche Natie,' or ' The Dutch Nation,' not 

 long before his death, which took place on the 26th of February 1813. 

 The work is divided into six cantos, the first treating of morality, the 

 second of heroism by land, the third of heroism at sea, the fourth of 

 navigation, the fifth of sciences, and the sixth of fine arts, in all of 

 which the ' Dutch nation' is represented as leaving all other nations 

 immeasurably in the rear. In the sixth canto we are gravely told 

 that "no Briton, no Gaul, no German, no Italian" will be admitted 

 by the poet to excel hia countrymen in the domain of the fine arts, 

 but he condescends to add that there was one race " that even more 

 than equalled it," and allows that the Greeks surpassed the Dutch. 

 In another passage he calls attention to the fact that hia countrymen 

 could boast of a Vondel, when the barbarism of Shakspcre still 

 sounded beautiful to British ears. The only excuse for the hyper- 

 bolicil laudation of his countrymen which pervades the poem is that 

 it was published at a period when Holland was lying crushed beneath 

 tho feet of Napoleon, and when a patriot might naturally revolt at 

 the contempt with which he saw the real glories of his country treated. 

 But though the poem contains passages of considerable merit, its 

 continued popularity is not creditable to the fine feelings of tustc, 

 which in one passage tho poet asserts is born with every Dutchman. 



HELMONT, JOHN BAPTIST VAN, was born at Brussels iu 1577, 

 the youngest son of a noble family, who derived their name from an 

 estate and castle in Brabant He has left an account of himself 

 prefixed to his ' Ortus Jledicinoo,' published at Amsterdam in 1015, 

 from which we learn that he was educated at the university of 

 Louvain, and intended for the church ; but was so dissatisfied with 

 the course of study there that he refused to take a degree when only 

 seventeen. He says he had studied Euclid and Copernicus, but had 

 no relish for them. He next tried metaphysics, which suited him (us 

 little. At length he applied to the medical sciences, particularly 

 botany and chemistry. He read he says Galen, Hippocratea, Avicenna. 

 and Greek, Arabian, and modern authors, to the number of aix 

 hundred, and after ten years study took a medical degree at Louvain ; 

 after which, being then married, he retired to Vilvorde in 1609. 

 There he employed himself in chemical investigations, and studied 

 Paracelsus, but says he found only obscurity and error iu him. His 

 memoir is a curious mixture of devotion and insanity. He had 

 arrived at the conclusion that all his books and hia acquired know- 

 ledge were a " mass of stuff," and ho prayed for and behaved he had 

 acquired spiritual help. He nevertheless effected some rcmarknblo 

 cures, particularly during a season of plague. For these he was arrested 

 by the inquisition as a sorcerer, but successfully cleared himself; 

 and to avoid a similar inconvenience he removed to Holland. He 

 has been reckoned among the alchemists, and no doubt many of his 

 experiments were in that direction ; but he also effected some service 

 in chemistry. It was he who first used the term gas to denote all 

 clastic fluids which differ from atmospheric air ; and he noticed some 

 of the properties of what ho called gas sylvestre, or carbonic acid gas. 

 Ho stated that it ia invisible, and fixed iu bodies; and he attributed 

 the phenomena of the Grotto del Cane to its presence. Hu died 

 December 30, 1644. He bad published several works iu his life time; 

 among them were 'De Magnetica Vulnerum Naturali ct Legitima 

 Curatioue,' 1621 ; ' Tho Ternary of Paradoxes ; the Magnetic Cure of 

 Wounds, the Nativity of Tartar in Wino, and the Image of God in 

 Man,' 4to, translated by W. Charleton in 1650. He likewise left a 

 considerable number of his writings, which he strictly enjoined his son 

 to have published in the state in which he left them. They were 

 issued in folio in 1618, and arc a continuous attack on tho Ualenists, 

 but of very little value. 



