. The science-history of the universe . •Franklins Experiment on the Action of Points. along the wax till you touch the blade, and the ball fliesto the shot immediately. If you present the point in thedark you will see, sometimes at a foot distance and more,a light gather upon it, like that of a firefly or glowworm;the less sharp the point the nearer must you bring it toobserve the light; and at whatever distance you see thelight, you may draw off the electrical fire and destroy therepellency. If a cork ball so suspended be repelled by thetube, and a point be presented quick to it, tis surpris
. The science-history of the universe . •Franklins Experiment on the Action of Points. along the wax till you touch the blade, and the ball fliesto the shot immediately. If you present the point in thedark you will see, sometimes at a foot distance and more,a light gather upon it, like that of a firefly or glowworm;the less sharp the point the nearer must you bring it toobserve the light; and at whatever distance you see thelight, you may draw off the electrical fire and destroy therepellency. If a cork ball so suspended be repelled by thetube, and a point be presented quick to it, tis surprising to 162 ELECTRICITY see how suddenly it flies back to the tube. Points of woodwill do near as well as those of iron, provided the wood isnot dry; for perfectly dry wood will no more conductelectricity than sealing-wax. It is calculated that the density of electricity at an. Fig. 7 —Action of Points : Electric Wind. infinitesimally fine point would be infinitely great, sinceit is impossible to charge a pointed conductor in the airwith electricity; this is proved by experiment. As fast aselectrification is produced, it is given off the point intothe air and disappears. When we examine the extremityof a point in the dark, there is seen a luminous crest. If,while the point is in communication with the source ofelectrification, one places ones hand before it, a draft ELECTROSTATICS 163 is at once perceptible, arising from the motions of theparticles of air. This can be still better shown by holdinga candle-flame in front of a long-pointed conductor. Theelectric wind is sufficient to bend the flame sharply down,or even to put it out. This movement of the air at the points on electrifiedconductors has always been attributed to the accumulationof electricity, which has been compared to a fluid; but thefollowing explanation seems to us preferable, as it in-volv
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