I made the following experiment, having placed a very large Jar in contact with my prime conductor, I fixed to the outer coating of it an Iron Chain 10 or 12 Inches long which I also connected with a plate of Metal on which I intended to make the discharge, with my discharging Rod. This done I hooked another chain much longer and of Brass to the side of the Jar, and brought the end of it within 8½ Inches of the Metal plate. In contact with this end I laid a small Oak-stick 8 Inches long which I cover’d with Sawdust of Fir wood. On making the discharge upon the plate, both the chains were luminous through their whole lengths, as was also the sawdust which was cover’d by a streak of Light near an Inch diameter making a very pleasing appearance. I repeated the experiment several times. Perhaps if I had used a Bar of Iron instead of the Chain (first spoken of,) there might have been no appearance of light in the second Chain or upon the sawdust; especially as the electricity had full ½ Inch of air to pass through, before it reached the point of the stick. But from this experiment may I think be inferred the necessity of making the Conductors erected as a security to Buildings from the damage of Lightning, both of the best materials, and of a very sufficient substance; and, for this purpose, perhaps nothing will be found so proper as lead, which will remain in the earth many centuries without any considerable decay; and the tops of chimneys being covered with it, and furnished with a long, sharp-pointed rod of copper, or iron pointed with copper, which I think should extend at least five, or six feet, above the top of the chimney, or highest part of the building; a communication should be made from it by plates of lead, eight, or ten inches broad, with the lead, on the ridges, and gutters, and with the pipes which carry down the rain-water; which pipes should be continued to the bottom of the building, and there made to communicate, by means of other leaden pipe, or a plate of it, as before-mentioned, with the water in a well, the moist earth, or the main pipe which serves the house with water.