for Electrical Experiments, I afterwards repeated the Trial, and found, that in warm Weather it would retain a manifeſt power of attracting for ſeveral minutes (for it ſtirred a pois'd Needle after above 14 of an hour) after we had done rubbing it. Upon which encouragement we ſuſpended it, being first well chafed, in a Glaſs Receiver that was not great, juſt over a light Body and making haſte with our Air Pump to exhauſt the Glaſs, when the Air was withdrawn, we did by a Contrivance let down the ſuſpended Amber till it came very near the Straw or Feather, and perceived, as we expected, that in ſome Trials, upon the leaſt Contact it would lift it up, and in others, for we repeated the Experiment, the Amber would raiſe it without touching it, that is, would attract it.
You will probably be the leſs diſpos'd to believe, That Electrical Attractions muſt proceed from the Subſtantial Forms of the Attrahents, or rom the Predominancy of this or that Chymical Principle in them, if I acquaint you with ſome odd Trials wherein the Attraction of light Bo-
dies
