426 



CATALOGUE. — ELECTRICITY. 



Nicholson. Ph. tr. 1789. 



IVi/ke de electricitatibus contrariis. Auf- 

 satze. 8. Gott. 1790. 



Finds that the friction of a quill, in different directions, 

 produces different species of electricity. 



Lichtcnberg in Erxleben. §. 514. 



Wilson on the electricity of shavings. Nich. 



8. IV. 49. Gilb. XVII. 205. 

 Gersdorf on the electricity of powder. Gilb. 



XVII. 200. 

 Haijy on the electricity of metals. Ph. M. 



XX. 120. 



Lichtenberg's Table of Excitation, transposed. 



The marks denote the electricity of the substances under which they stand. 



Polished glass 



Hair 



Wool 



Feathers 



Paper 



Wood 



Wax 



Sealing wax 



Ground glass 



Metals 



Resin 



Silk 



Sulfur 



Polished 



glass. 







+ 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



Hair. 



Wool. Feathers. Paper. Wood. Wax. Sealing Ground Metals. Resin. Silk. Sulfur. 



wax. glass. 



+ 

 + 



+ 

 + 

 + 



+ 

 + 



o 



+ 



+ 

 + 



o 



+ 

 + 



It appears that any substance in this table, rtibbed with any of the following substances, becomes positively electric j 

 with any of the preceding, negatively. This proposition is, however, liable to some modifications, according to the mode 

 of applying friction, and the degree of heat ; the table requires also some further subdivisions. 



Mr. Henley says, that " a smooth glass mbe maybe made negative by drawing it crosswise over the back of a cat, or 

 by exciting it with a dry, warm rabbit's skin." Henley made a great number of experiments with a variety of sub- 

 stances rubbed on wool and silk : there are only two instances where the wool produced a positive and the silk negative 

 electricity, and these were probably owing to the greater heat of the wool. There were, however, very great irregularities 

 in the effects produced upon different substances of the same class ; thus a guinea, a sixpence, and a piece of tin, became 

 negative ; a piece of copper, a steel button, and a silver button, positive, at least when the cloth was warm : animal sub- 

 stances, excepting shells, generally positive : vegetables almost always negative, but the smooth skins of beans positive ; 

 common pebbles, marble, coal, and jet, negative : gems and crystals positive : glazed wares and writing paper positive; 

 tobacco pipe, clastic gum, a tallow candle, oiled silk, Indian ink, and blue vitriol, negative. Mr. Errington and Mr. 

 Cavallo extended the list to almost looo articles. 



Excitation bi/ Change of Form of Aggregation. 



Gray on melted substances. Ph. tr. 1732. 



XXXVII. 285. 

 Kinnersley. Ph. tr. 17G3. 84. 



The vapouf of electrified water did not carry up elec- 

 tricity. 



Henley on the positive electricity of cooling 

 chocolate. Ph.tr. 1777.85. 



Lavoisier and Laplace on the electricity ab- 

 sorbed by vapours. A. P. 1781. 292. 

 H. 6. 



Bennet. Ph. tr. 1787- 



Water running through a heated tobacco pipe showed a 

 strong electricity. 



Liphardt on the electricity of chocolate. 

 Roz. XXX. 434. 



