LICHTENBERG

lichtenberg, georg christoph (1742-1799), german physicist and satirical writer, was born at oberramstadt, near darmstadt, on the 1st of july 1742. in 1763 he entered gottingen university, where in 1769 he became extraordinary professor of physics, and six years later ordinary professor. this post he held till his death on the 24th of february 1799. as a physicist he is best known for his investigations in electricity, more especially as to the so-called lichtenberg figures, which are fully described in two memoirs _super nova methodo motum ac naturam fluidi electrici investigandi_ (gottingen, 1777-1778). these figures, originally studied on account of the light they were supposed to throw on the nature of the electric fluid or fluids, have reference to the distribution of electricity over the surface of non-conductors. they are produced as follows: a sharp-pointed needle is placed perpendicular to a non-conducting plate, such as of resin, ebonite or glass, with its point very near to or in contact with the plate, and a leyden jar is discharged into the needle. the electrification of the plate is now tested by sifting over it a mixture of flowers of sulphur and red lead. the negatively electrified sulphur is seen to attach itself to the positively electrified parts of the plate, and the positively electrified red lead to the negatively electrified parts. in addition to the distribution of colour thereby produced, there is a marked difference in the _form_ of the figure, according to the nature of the electricity originally communicated to the plate. if it be positive, a widely extending patch is seen on the plate, consisting of a dense nucleus, from which branches radiate in all directions; if negative the patch is much smaller and has a sharp circular boundary entirely devoid of branches. if the plate receives a mixed charge, as, for example, from an induction coil, a "mixed" figure results, consisting of a large red central nucleus, corresponding to the negative charge, surrounded by yellow rays, corresponding to the positive charge. the difference between the positive and negative figures seems to depend on the presence of the air; for the difference tends to disappear when the experiment is conducted in vacuo. riess explains it by the negative electrification of the plate caused by the friction of the water vapour, &c., driven along the surface by the explosion which accompanies the disruptive discharge at the point. this electrification would favour the spread of a positive, but hinder that of a negative discharge. there is, in all probability, a connexion between this phenomenon and the peculiarities of positive and negative brush and other discharge in air. as a satirist and humorist lichtenberg takes high rank among the german writers of the 18th century. his biting wit involved him in many controversies with well-known contemporaries, such as lavater, whose science of physiognomy he ridiculed, and voss, whose views on greek pronunciation called forth a powerful satire, _uber die pronunciation der schopse des alten griechenlandes_ (1782). in 1769 and again in 1774 he resided for some time in england and his _briefe aus england_ (1776-1778), with admirable descriptions of garrick's acting, are the most attractive of his writings. he contributed to the _gottinger taschenkalender_ from 1778 onwards, and to the _gottingisches magazin der literatur und wissenschaft_, which he edited for three years (1780-1782) with j. g. a. forster. he also published in 1794-1799 an _ausfuhrliche erklarung der hogarthschen kupferstiche_. lichtenberg's _vermischte schriften_ were published by f. kries in 9 vols. (1800-1805); new editions in 8 vols. (1844-1846 and 1867). selections by e. grisebach, _lichtenbergs gedanken und maximen_ (1871); by f. robertag (in kurschner's _deutsche nationalliteratur_ (vol. 141, 1886); and by a. wilbrandt (1893). lichtenberg's _briefe_ have been published in 3 vols, by c. schuddekopf and a. leitzmann (1900-1902); his _aphorismen_ by a. leitzmann (3 vols., 1902-1906). see also r. m. meyer, _swift und lichtenberg_ (1886); f. lauchert, _lichtenbergs schriftstellerische tatigkeit_ (1893); and a. leitzmann, _aus lichtenbergs nachlass_ (1899).