“From the instances which now and then occur of houses being struck with lightning, that are furnished with metallic conductors, and the frequent instances of these conductors having their tops melted off by a stroke of lightning, it appears that this admirable contrivance for guarding houses against the dangerous effects of lightning is, in some degree, still imperfect. Some improvement seems yet to be wanting at both extremities of the rod—at the upper extremity, to secure it against the accident of being melted, which renders it afterwards unfit to answer its original intention, viz. drawing off the electricity, or lightning, from the passing cloud, in a silent imperceptible manner, for it is only _pointed_ conductors that possess this property—and at the lower extremity, to afford a more ready passage for the fluid into the surrounding earth. The first of these intentions, would I am persuaded, be effectually answered by inserting in the top of the rod a piece of _black lead_, of about two inches long, taken out of a good pencil, and terminating in a fine point, projecting but a very little above its metallic socket; so that if the black lead point should happen to be broken off by any accident, of which however I think there can be but little danger, still the point of the rod would be left sharp enough to answer the purpose of a metallic conductor. This substance is well known to be infusible, by the greatest heat, and hence its use in making crucibles; nor is it evaporable as remarked by Cronstedt, in his mineralogy, Sect. 231, except in a slow calcining heat, to which it could never be exposed at the top of a lightning rod. At the same time its power as a conductor of electricity is perhaps equal, or but little inferior, to that of any of the metals. A line drawn on a piece of paper by a black lead pencil, will as I have often experienced, conduct an electric explosion seemingly as well as a similar line of gilding would do, and that without ever loosing its conducting power, which is not the case with gilding. The second intention is, to facilitate the escape of the electric fluid from the lower part of the rod into the surrounding earth.