HEINRICH

GEISSLER (1814-1879)  , German physicist, was born at the village of Igelshieb in Saxe-Meiningen on the 26th of May 1814 and was educated as a glass-blower . In 1854 he settled at Bonn, where he speedily gained a high reputation for his skill and ingenuity of conception in the fabrication of chemical and physical apparatus . With Julius Plucker, in 1852, he ascertained the maximum density of water to be at 3.8° C . He also determined the coefficient of expansion for ice between -24° and -7°, and for water freezing at o° . In 1869, in con-junction with H . P . J . 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 . Among other apparatus contrived by him were a vaporimeter, mercury air-pump, balances, normal thermometer, and areometer . From the university of Bonn, on the occasion of its jubilee in 1868, he received the honorary degree of doctor of philosophy . He died at Bonn on the 24th of January 1879 .

See A . W .

Hofmann, Der. d. deut. chem . Ges. p . 148 (1879) .