_Origin of Laws, Arts, and Sciences_, Vol. III, Book III, Chap. II, Article IV. Footnote 4: Bayle in Vita Aristot. Footnote 5: Gilbert, De Magnete. Lib. 2, Cap. 2. Footnote 6: Philos. Trans. abridged, Vol. 7, page 18. Footnote 7: The author of the article Electricity in the Encyclopædia, ascribes the merit of this discovery (if any merit can arise from a discovery made by accident) to Mr. Van Kleist, dean of the cathedral of Camin. On what authority he does this, we are unable to state. The following (he says) is the account of it, which the dean, on the 4th of November 1745, sent to Dr. Leiberkulm at Berlin, “When a nail, or a piece of thick brass wire, &c. is put into a small apothecary’s phial, and electrified, remarkable effects follow: but the phial must be very dry, or warm. I commonly rub it over before-hand with a finger, on which I put some pounded chalk.—If a little mercury or a few drops of spirit of wine are put into it, the experiment succeeds the better. As soon as this phial and nail are removed from the electrifying glass, or the prime-conductor to which it hath been exposed is taken away, it throws out a pencil of flame so long, that with this burning machine in my hand, I have taken above sixty steps in walking about my room. When it is electrified strongly, I can take it into another room, and there fire spirits of wine with it. If while it is electrifying I put my finger, or a piece of gold which I hold in my hand, to the nail, I receive a shock which stuns my arms and shoulders.” “A tin tube, or a man, placed upon electrics, is electrified much stronger by this means, than in the common way.—When I present this phial and nail to a tin tube, which I have, fifteen inches long, nothing but experience can make a person believe how strongly it is electrified. Two thin glasses have been broken by the shock of it.” Footnote 8: Such is the statement usually given. It may perhaps deserve consideration whether _the cause_ of this luminous spark or stream, should not, strictly speaking, be considered as the true electricity. Footnote 9: Tourmaline is a species of silicious earth. Its colour is generally a blackish brown, though the tourmaline of Brazil is blue, green, red, or yellow. It is a compound substance, consisting of argill, silex, calcareous earth, and iron in different proportions; but argill and silex are always the chief ingredients. It is found in Ceylon, Brazil, and Tyrol; and it is also found in large quantities in the neighbourhood of Philadelphia, attached to masses of quartz. Footnote 10: It is very remarkable that the focus of a burning glass is not a conductor of electricity. Footnote 11: We do not wish to be understood that _two different_ fluids may be produced, but merely, that the prime conductor may be electrified _positively_ or _negatively_. Footnote 12: For the proper cement, see appendix NO. I.