Page:Works of the Late Doctor Benjamin Franklin (1793).djvu/113

103 contained no more electricity than before, but that as much was taken from one ſide as was thrown on the other; and that, to diſcharge it, nothing was neceſſary but to make a communication between the two ſides, by which the equilibrium might be reſtored, and that then no ſigns of electricity would remain. He afterwards demonſtrated, by experiments, that the electricity did not reſide in the coating, as had been ſuppoſed, but in the pores of the glaſs itſelf. After a phial was charged, he removed the coating, and found that upon applying a new coating the ſhock might ſtill be received. In the year 1749, he firſt ſuggeſted his idea of explaining the phenomena of thunder-guſts, and of the aurora borealis, upon electrical principles. He points out many particulars in which lightning and electricity agree; and he adduces many facts, and reaſoning from facts, in ſupport of his poſitions. In the ſame year he conceived the aſtoniſhingly bold and grand idea of aſcertaining the truth of his doctrine, by actually drawing down the forked lightning, by means of ſharp-pointed iron rods raiſed into the region of the clouds. Even in this uncertain ſtate, his paſſion to be uſeful to mankind diſplays itſelf in a powerful manner. Admitting the identity of electricity and lightning, and knowing the power of points in repelling bodies charged with electricity, and in conducting their fire ſilently and imperceptibly, he ſuggeſts the idea of ſecuring houſes, ſhips, &c. from being damaged by lightning, by erecting pointed iron rods, which ſhould riſe ſome feet above the moſt elevated part, and deſcend ſome feet into the ground or the water. The effect of theſe, he concluded, would be either to prevent a ſtroke by repelling the cloud beyond the ſtriking diſtance, or by drawing off the electrical fire