[12]. For the proper cement, see appendix NO. I.
[13]. See appendix NO. II.
[14]. See appendix NO. III.
[15]. This consists of two small balls of cork or pith, fastened to the ends of a thread or piece of silk. When it is to be used the thread or silk must be held by the middle so that the balls may hang close to one another.
[16]. Mr. Richman, professor at Petersburg, was killed on the 6th of August, 1753, by the lightning which he had drawn into his room, for the purpose of making experiments. The circumstances of this interesting and instructive occurrence were the following.
He had provided himself with an instrument for measuring the quantity of electricity communicated to his apparatus, and as he stood with his head inclined towards it, Mr. Solokow, an engraver, who was near him, observed a globe of blue fire as large as his fist, jump from the instrument, which was about a foot distant, to Mr. Richman’s head. The professor was instantly dead, and Mr. Solokow much hurt. The latter however could not give any particular account of the way in which he was affected; for at the time when he was struck, there arose a sort of steam or vapour, which entirely benumbed him, and made him sink to the floor; he did not even remember to have heard the clap of thunder, which was very loud.—The globe of fire was attended with an explosion like that of a pistol; the instrument for measuring the electricity (called by the professor the electrical gnomon) was broken to pieces, and the fragments scattered about the room. Upon examining the effects of the lightning in the chamber, the door-case was split half through, and the door torn off the hinges, and thrown into the room.
They opened a vein in the body twice, but no blood followed; after which they endeavoured to recover life by violent friction, but in vain: upon turning the corpse with the face downwards, during the friction, a quantity of blood ran from the mouth. There appeared a red spot upon the forehead, from which spirted a few drops of blood from the pores, without wounding the skin; the shoe of the left foot was torn open, and upon uncovering the part, a blue mark was found; from which it was concluded, that the electric matter having entered at the head, made its way out again at the foot. Upon the body, particularly on the left side, were several red and blue spots, resembling leather shrunk by being burnt. Many more also became visible over the whole body, and especially over the back.—That on the forehead changed to a brownish red, but the hair of the head was not singed.
In the place where the shoe was unripped, the stocking was entire, as was the coat every where; the waistcoat being only singed at the fore flap where it joined the hinder; but on Mr. Solokow’s coat there appeared long narrow stripes, as if the nap had been burnt off by red hot wires. These could not be accounted for.
[17]. This looks something like a contradiction: but we suppose Mr. Cavallo intended to say, that though the coat of paint does not prevent the shock from passing down the mast, it prevented the mast from being injured by the shock.
[18]. For proper cement, see Appendix to electricity, No. I.