HELMOLD
212
HELMONT
ad meridianum Vindobonensem", which he began in
1757 and continued for many j'ears. These contain
a large number of valuable observations and data. He
was invited by the King of Denmark to undertake at
Vardohuus, Norway, the observations of the transit
of Venus of 1769. The transit observations were suc-
cessful, and after spending some months at Copen-
hagen preparing his results for the press, he returned to
Vienna in 1770. Owing to delays in publication Hell
was afterwards suspected of manipulating his data to
make them fit in with others taken elsewhere. The
suspicion was strengthened by Littrow when director
of the Vienna Observatory, after a study of the original
manuscripts (cf. Hell's "Reise nach Wardo u. seine
Beobachtung des Venus-Durchgangs in Jahre 1769",
Vienna, 18.35). It was not until 1890 that Father
Hell's reputation was cleared of the stain of forgery by
Prof. Simon Newcomb, who made a critical study of
the journal in question and showed conclusively that
Littrow's inferences were entirely at fault. The latter,
it appears, had originally been led into error by a de-
fect in his sense of colour. Father Hell was of a gentle
disposition and simple in his tastes. His devotion to
the Church and to his order often cost him much
persecution. Besides the " Ephemerides", he was also
the author of " Elementa algebra? Joannis Crivelli
raagis illustrata" (Vienna, 1745); " Adjumentum mem-
oris manuale chronologico-genealogico-historicum"
(Vienna, 1750) ; " De la celebration de la Paque" (ibid.,
1761); Elementa arithmetical numericae et litteralis"
(ibid., 176.3); "De satelhte Veneris" (ibid., 1765);
"De Transitu Veneris" (Copenhagen, 1770), etc.
ScHLlciiTEGROLL, Nekroloa. (Gotha, 1792), I, 282; Sommer- VOGEL, Bibl. de la C. de J., IV, 238; Wolf, Geschichle der Astronomic (Munich, 1877), 64.5; Newcomb, Month. Notices Royal Astron. Soc, XLIII, 371; Idem, Heminiscences of an Astronomer (Boston, 1903); Woodstock Letters, XXI, i, 70.
Henry M. Brock.
Helmold, historian, b. in the first half of the twelfth century; d. about 1177. He was a native of, or at least he grew up in, Holstein (Germany), and received his instruction in Brunswick from Ceroid, the future Bishop of Oldenburg. Later he came under the direction of the saintly Vicelinus, the Apostle of the Wends, first in the Augustinian monastery of Fal- dera, afterwards known as Neumiinster. He finally became a parish-priest at Bosow on Plcine See. He wrote, at Gerold's suggestion, a chronicle of the Wends (" Chronica Slavorum " or " Annales Slavorum "), the purpose of this chronicle was to demonstrate how Christianity and German nationality gradually suc- ceeded in gaining a footing among the Wends, especi- ally in the eastern portion of Holstein. As an eye- witness he gives a clear de.scription in fluent Latin of Vicelinus's self-sacrificing missionary labours, of the founding of the bishopric in Oldenburg, of the transfer of this bishopric to Liibeck when German commerce at the latter place had become more important than in the former city, of the spread of German influence among the Wends, of the merciless subjugation and extermi- nation of these, and of the summoning to their lands of foreign settlers, principally Westphalian and Dutch. The work is divided into two parts: the first covers a period closing with the year 1168, while the second continues to the year 1171. This second part, how- ever, was written subsequently to 1172. He drew his knowledge of the earliest period from the church history of .\dam of Bremen and the Saxon records bearing on Henry IV, besides the life of Willehadus, the list of .\nsgarius, and perhaps also a life of Viceli- nus, but the summaries which he made of these records are unreliable. He is, however, our most important source of information for the historj' of his own period, his accoimt of which rests on the verba! information of Vicelinus and of Ceroid. His fund of information becomes noticeably meagre after the latter's death in 1163. His trustworthiness has been very seriously
questioned in recent times (see particularly Schirren,
" Beitrage zur Kritik holsteinischer Ceschichtsquel-
len", Leipzig, 1876) owing to his antagonism towards
the archbishops of Bremen and his partiality for the
Oldenburg-Lubeck bishopric, but it shoulcl not be
supposed that he was guilty of an intentionaJ falsifi-
cation of facts [cf. with vSchirren's observations and
conclusions Wigger, " Ueber die neueste Kritik des
Helmold" in "Jahrbiicher des Vereins fiir Mecklen-
burgische Geschichte", XLII (1877), 21-63]. The
chronicle was first publi-shed in 1556 at Frankfort on
the Main, and finally in " Mon. Germ. Hist.: Script. ",
XXI (1868), 11-99, and in "Script, rer. Germ."
VVattenbach, DeulsMandsGrsrhichtsqurUm, II (IS94), 338- 41; PoTTHAST, Bibliotheva historiea, 1 (1S96). 576.
Patkicius Schlageb.
Hehnont, Jan Baptist.*, v.vn; b. at Brussels, 1577; d. near Vilvorde, 30 December, 1644. This scientist, distinguished in the early annals of chemistry, be- longed to a good Flemish family. He was brought up by his uncle, and studied humanities at Louvain, but refused to take his degree of Master of Arts, on the theory that it was a source of priile. The .Jesuit order attracted him, but he did not enter it. He investigated the Stoic school of philosophy, and, to practise the evangelical counsel of poverty, he conveyed all his property to his sister. Urged on by a desire to relieve human suffering, he began to study medicine. He was appointed to the chair of surgery at Louvain. The course of his studies was interfered with by a sickness, scabies, which affected him. The tialenists treated him with purgatives, not recognizing that it was a parasitical disease. This disgusted him with the Galenists; and he began his travels through Eng- land, France, Switzerland, and Italy, for the purpose of investigating the practice of medicine in these different countries. Eventually he was healed by an Italian charlatan, who used sulphur and mercury. He practised as a physician and, instead of using plants, prepared his medicines in the laljoratory of the ilay, in which the furnace, crucible, and retort were most largely employed ; this made him known as the medicus per ignem. He departed somewhat from the counsel of poverty by marrying Margaret van Ranst, an heiress of Brabant, and settled down at Vih'orde. He had now acquired a wide repvitation in medicine, and had received his doctor's degree at Louvain as early as 1599. Yet he failed in the treatment of his own family; and, in spite of his remedies, death carried off one of its members when att;icked by scabies, the very disease of which he had been cureil. His celeb- rity was now very great, and it is s;iid that he was suspected of diabolism. \ fantastic element ai)pears in his work, largely due to the age in which he live<l; but his scientific work is of a high order of merit. He investigated gases, notably carbon dioxide, which he discovereil in various sources, and it was he who first applied the name gas (gei.il) to this family of sub- stances. He applietl the balance in his investigations. He discovered sulphuretted hydrogen in the Imman system, made hj'drochloric gas, which he called gas of salt, explained the explosion of gun-powder on the theory of the expansion of gases, discovered or inves- tigated sulphuric acid, nitric acid, and nitrogen oxitie. He was one of the first to recognize the role played by acid in the gastric juice, attributing disease to an excess of the same. Like all other chemists of the time, he studied the transmutation of metals, naming his son Mercury, believing that he had succeeded in getting gold from mercury. His various books were
Cubhsheil from 1622 to 16.52, In 164S a collection of is works was published posthumously under the au- spices of his son.
Poui.TiER d' Helmoth, AUmoires 8ur van Hetmont et aea (n-its (Brussels, 1847); Rommelaere, Eludes sur Ilelmont (Brussels, 1868).
T. O'Connor Sloane.
