The principal work published by this astronomer was a series of Ephemerides in thirty-five volumes, 8vo, the collectiou being entitled Ephemerides Anni 1757 -1791 ad Meridianum Vindoboneusem Calculis definitse.' With the exception of two volumes, these contain appendixes on astronomical subjects by himself or other scientific men, chiefly by Pilgram and Triesnocker; the former of whom edited the work during the absence of hell in Lapland. The rest of his publica tions ou astronomical subjects are as follow :—'Tabules Solares NicoL Ludov. do Is Caille cum Supplemento Reliquarum Tabularum,' 1763; ' Tabula) Lunares Tob. Mayer cum Supplemento, etc.,' 1763; De Satellite Veneris,' 1765; 'Do Transits' Vcneris ante Discum Solis die 3 Jun., 1769, Wardochneli observato,' 1770; ' De l'arallaxi Solis ex Obeervationibus Trausitfis Veoeris, anni I769,' 1773 ; and Methodue Astronomica sine Usu Quadmntis, etc.,' 1775. lIe also edited a col lectloo, which had been made' by Hallerstein, of the astronomical observations made by the Jesuits at l'ekin from 1717 to 1752; this was published at Vienna, in 2 vols. 4to, iu 1768.
Besides these works he published 'Elements Algebras J. Crivellii,' 8vo, 1745; 'Adjumentum Memories Manualo Chronologico-Genealogico Ilistoricum; 10mo, 1750; ' Elements Arithineticto Numeric:is et Lite rails; 8vo, 1763 ; also a tract on the true magnitudes of the sun aud moon when seen by the naked oye, 1775; and one on a' New Theory of the Aurora Borealis,' 1770.
All his works were published at Vienna; and he died in that city, April 14, 1792, being seventy-two years of age. A brother of Hell was a distinguished inechauiolan at Schemnitz, and the inventor of a sort of siphon for draining mines: this is described in the ' Mdmoirea de l'Aead6mio doe Sciences de Paris' for the year 1760.
(Biographic (Aim-relic ; Delambro, Kist. de 1 'ct stronomie au Di.c huitittne &Mc.) lIELLA'NICUS, one of tho early Greek prose writers, was born at Mitylene in the Island of Lesbos, me. (' Gell.,' xv. 23). According to Lucian (' Macrob.,' c. 22) he lived to the age of eighty-five. Suidas &aye that ho lived at the court of Amyntas, king of Macedon, together with Herodetus; but this statement is inaccurate, since there was no king of Macedon of the name of Amyntas during the lives of Hella nicus or Hcrodotus.
He wrote several works, which are frequently quoted by ancient writers ; of which the most important appear to have been, a 'History of Argos,' arranged in chronological order, according to the successive priestesses of the temple of Hera in that city ; a ' History of Attica, Cyprus, fEolia, mud Lesbos ;' an account of Plmenicia, Persia, Scythia, aud other Eastern nations, and some geographical pieces. Hellanicus is mentioned by Thueydides (i. 97).
The fragments which remain of the writings of Hellanieue were published by Sturz, 8vo, Leip., 1787; 2nd edition, 1523; and in the Museum Criticum,' voL ii., pp. 90-107, Camb., 1826.