But Mr. Cavallo with all his caution could not avoid danger in making experiments on atmospheric electricity, as appears from the following account of his observations on the 13th of October 1773. “After having rained a great deal in the morning and the night before, the weather became a little clear in the afternoon, the clouds appearing separated and pretty well defined; the wind was west and pretty strong; the atmosphere was in a temperate degree of heat. In these circumstances, at three o’clock P. M. I raised my electrical kite, with 360 feet of string. After the end of the string was insulated, and a leather ball coated with tin foil, hung to it, I tried the power and quality of the electricity, which appeared to be positive and pretty strong; in a short time a small cloud passing over, the electricity increased a little; but the cloud being gone it returned pretty soon to its former degree. The string of the kite was now fastened by a silk string to a post in the yard of the house; I was repeatedly charging two phials, and giving shocks with them: while I was so doing, the electricity, which was still positive, began to decrease, and in two or three minutes it became so weak, that it could hardly be perceived, with a very sensible cork ball electrometer.—Observing at the same time that a large black cloud approaching the zenith, (which no doubt caused the decrease of electricity) indicated rain, I introduced the end of the string through the window on the first floor, where I fastened it by the silk to an old chair.—The quadrant electrometer was set upon the same window, and was, by means of a wire, connected to the string of the kite. Being now three quarters of an hour after three, the electricity was actually imperceptible, however in about three minutes it returned, but now upon examination, it was found to be negative, which was evidently occasioned by the approach of the cloud, which by this time had reached the zenith of the kite; the rain also began to fall in large drops. The cloud came farther on, the rain increased and the electricity keeping pace with it, the electrometer soon arrived at 15°. Seeing now that the electricity was strong, I began again to charge the phials and to give shocks with them; but the phials had not been charged more than three or four times, before I perceived that the index of the electrometer was arrived at 35°, and was still rising. The shocks now being very smart, I desisted from charging the phials, and considering the rapid advance of the electricity, thought to take off the insulation of the string, that if it should farther increase it might be conducted silently to the earth, without occasioning any bad accident.