Leyden Jar
2 of the 7 encyclopedias on this shelf carry an entry for Leyden Jar. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a well known piece of electrical apparatus. It was invented in 1746 by Cuneus, a professor in the University of Leyden, Holland. The jar is simply a condenser. It consists essentially of a jar coated within and without with tin foil for about two-thirds of the height. A brass rod passes inside, through a stopper, a chain connects the inner end of the rod with the inner coating. The outer end of the rod terminates in a knob. The jar may be charged by bringing one of the coatings into connection with the conductor of an electrical machine and connecting the other coating with the ground. The coats will become charged with opposite kinds of electricity which attract each other but are kept apart by the glass wall of the jar. If the knob be connected with the outer coating the charges leap together. If the outer coating be touched with one hand and the knob with the other, the charge will pass through the body, imparting a shock, which, in the case of a large jar powerfully charged, is sufficient to cause death. The ordinary strokes of lightning are discharges of a similar nature. The earth and a cloud are the coatings; the air which separates takes the place of the glass of the jar. The bolt of lightning is the discharge.
Collier's New Encyclopedia (1921)
a glass bottle having its interior coated with tin foil or filled with thin leaves of copper or of gold per or leaf. The outside is also coated with tin costed foil up to a certain distance from the tance neck. The neck has a cork, through cork which passes a brass rod terminating at one end in a knob, and communicating The inwith the metal in the interior. ner coating is called the internal, and the outer one the external armature or coating. It is charged by connecting one of the armatures with the ground and the other with the source of electricity. If the hand grasps the external coating while the knob is presented to the conductor of the machine, positive electricity accumulates on the inner, and negapart of the tive electricity on the outer coating. If, ty of peace on the contrary, the jar be held by the = knob and the outer coating be presented fer elibation. to the machine, positive electricity is acxii: 174). Lib cumulated on the outer, and negative on the mixed ed wine ( inner. etimes of