period a centre of attraction to some of the most earnest spirits of the time. Made a doctor of theology in 1475, he received a professorship at Freiburg in the following year; but his tastes began to incline him more strongly to the vocation of a preacher, while his fervour and elo- quence soon led to his receiving numerous invitations to the larger towns. Ultimately he accepted in 1478 a call to the cathedral of Strasburg, where he continued to work with few interruptions until within a short time of his death, which occurred on the 10th of March 1510. The beautiful pulpit erected for him in 1481 in the nave of the cathedral, when the chapel of St Lawrence had proved too small, still bears witness to the popularity he enjoyed as a preacher in the immediate sphere of his labours, and the testimonies of Sebastian Brandt, Beatus Renanus, Reuchlin, Melanchthon, and others who survived him, abundantly show how powerful, how healthy, and how widespread had been the influence of his personal character. His sermons—bold, incisive, abounding in quaint illustrations, nor altogether wanting in instances of what would now be called bad taste—taken down as he spoke them, and circulated (sometimes without his knowledge or consent) by his friends, told perceptibly on the German thought as well as on the German speech of
his time.
Among the many volumes published under his name only two appear to have had the benefit of his revision, namely, Der .S'celen Paradies con warm and vollcomncn Tugcndcn, and that l ntitled Das irrl'g Sclmf. Of the rest, probably the best known is a series of lectures on his friend Seb. Brandt’s well-known work the Navicula or Speculum Fatuorum, of which an edition was pub- lished at Strasburg in 1511 under the following title :—1\'avicula sz'zw speculum fatuorum prwstantz'ssimi sacrarum literarum doctoris Joannis G'eilcr Kcyscrsbcrgi-i corwiomztorz's Argentincnsis in scrmoncs jurta tumtarum scricm divisa ; suis figuris jam sz'gm'ta; atque a Jacobo Othero diligentcr collecta. C'ompcmiz'osa vita: cjusdcm dc- vcriptz'o per Bedlam Rhemmum Sclcstati'num.
See You Ammon, Geyler‘s Leben. Lehren, und l’redigten (1826); Stiiber, Essai lliflorique et Littéraire sur la Vie et les Sermons dc Geiler (1834); and C. Schmidt in llerzog‘s Real—Encycl., iv. 714 (1855).
GEISSLER, Heinrich (1811–79), a distinguished practical physicist, was born at the village of Igelshieb in Saxe-Meiningen, Germany, where he was educated as a glass-blower. After many years spent in travelling from city to city in the exercise of his craft, he settled at Bonn, where he speedily gained a high reputation, not only for his surpassing skill and ingenuity of conception in the fabrica- tion of physical apparatus, but for his comprehensive know- ledge, acquired chiefly in later life, of the natural sciences. With Pliicker, in 1852, by means of an ingeniously eon- trived instrument, in which mercury was made to compen- sate fer the expansion of the glass, he ascertained the maximum density of water to be at 38° C. He also de- termined the coefficient of expansion for ice between — 21° and — 7°, and for water freezing at 0°. In 1869, in conjunc- tion w ith Vogelsang, he proved the existence of liquid carbon dioxide in cavities in quartz and topaz, and later he obtained amorphous from ordinary phosphorus by means of the electric current. He is best known as the inventor of the sealed glass tubes which bear his name, by means of which are exhibited the phenomena accompanying the discharge of electricity through highly rarefied vapours and gases (see Electricity, vol. viii. p. 64). Among other apparatus contrived by him are his vaporimeter, mercury air-pump, balances, normal thermometer, and areometer. From the university of Bonn, on the occasion of its jubilee, he re- ceived the honorary degree of doctor of philosophy. He died on the 24th of January 1879, in the sixty-fifth year of his age. See A. W. Hofmann, Ber. d. dent. chem. Ges., 1879, p. 148.
GELA, an ancient city on the south coast of Sicily, on a river of the same name, near the site of the modern Terranuova between Girgenti and Camerina. Founded by a joint colony of Cretans and Rhodians (the latter mainly from the city of Lindus), and it soon rose to wealth and power, and by 582 b.c. it was able to become the mother-city of Agrigentum, by which it was however destined before long to be surpassed. The most important among its rulers were the foi.owiug :—Uleander, who subverted the oligarchy and made himself despot (505–498 b.c.) ; Hippocrates, his brother, who raised Gela to its highest pitch of eminence (498–491 b.c.) ; Gelon, who immediately succeeded Hippocrates, and rapidly pursued the same career of aggrandizement till in 485 b.c. he got possession of Syracuse, and gave the first blow to his native city by removing the seat of government to his new conquest; and finally llicro, the brother of Gelou, who succeeded to the sovereignty in 478 b.c. The decadent Gela was laid waste by Phalaris of Agrigentum, and in the time of Strabo it was nothing more than a heap of ruins. Aeschylus died at Gela in 450 b.c.; and it was the birthplace of Apollodorus, a comic poet of note.
GELASIUS, the name of two popes.
Gelasius I. succeeded Felix III. in 492, and confirmed the estrangement between the Eastern and Western Churches by insisting on the removal of the name of Acacius, bishop of Constantinople, from the diptychs. He was also the first decidedly to assert the supremacy of the papal over the imperial power, and the superiority of the pope to the general councils. He is the author of De duabus in C/zrislo mum-is adversus Eulyc/zen (t A'wlw-z’mn. Five of his letters have also come down to us, and he is mOst probably the author of Liber Sacrrmzento-rum, pub- lished at Rome in 1680 5 but the so-called Decrdum Gelusii dc libr-z's recipiemlis ct non rccz'piemlis is evidently a forgery. Gelasius died in 490, and was canonized, his day being the 18th November.
Gelasius II. (Giovanni da Gaeta) was of noble descent, and was born at Gaeta about 1050. He received his theological education in the abbey of Monte Casino, and afterwards held the office of chancellor under Urban II., and of cardinal-deacon under Pascal II. On the death of Pascal II. he was elected pope by the cardinals, 18th January 1118, and when his person was seized by Cencius Frangipani, a partisan of the emperor Henry V., he was almost immediately set at liberty through the general uprising of the people in his behalf. The sudden appearance of the emperor, however, compelled him to leave Rome for Gaeta, and the imperial party chose an anti-pope, Burdinus, archbishop of Braga, under the name of Gregory VIII. Gelasius, at a council held at Capua, fulminated bulls of excommunication against his ecclesiastical rival and the emperor; and under the protection of the Norman princes he was able to return to Rome, where he stayed for a time in partial concealment, but having barely escaped capture by the Frangipani while celebrating mass in the church of St Praxede, he left the city, and after wandering through various parts of Italy and France died in the abbey of Clugny, January 19, 1119.
GELATIN. When intercellular connective tissue, as met with in skin, tendons, ligaments, and the fascize of the muscles, of which it forms the basis, is treated with water, preferably hot, or in presence of dilute acids, for some time, a solution is obtained which in cooling solidifies to a jelly. The dissolved substance bears the name of Gelatin or Glulz'n.
is submitted to similar treatment, after previous removal of the lime salts by means of mineral acids. Again, when unossified cartilage, as for instance the bone-cartilages of the vertebrate foetus, is treated with water or dilute acids, a solution is obtained which also gelatinizes on cooling. The coagulation in this case, however, is due, not to gelatin,
but to a closely allied substance called chondrin. At one