If the wires within the tube be pointed, the illumination will be the same; but it seems not so strong in this as in the other case. _The electric Light flashing between two metallic Plates._ Let two persons (one standing upon an insulated stool communicating with the prime-conductor, and the other upon the floor,) each hold in his hand a polished metallic plate, in such a manner that their surfaces may be parallel, and about two inches asunder. Upon turning the cylinder, you will see the flashes of light between the two plates, so dense and frequent, that you can easily perceive any thing in the room. By this experiment the electric light is exhibited in a very copious and beautiful manner, and bears a strong resemblance to lightning. _The spiral Tube._ This instrument is composed of two glass tubes, one within the other, and furnished with a metallic ball at each end. The innermost tube has a spiral row of small round pieces of tin-foil, stuck upon its outside surface, and lying at the distance of one thirteenth of an inch apart. Now if the tube be held by one of its extremities, while the other is presented to the prime-conductor, every spark that is received from the conductor, will cause small sparks to appear between all the round pieces of tin-foil upon the inner tube, which in the dark appears encompassed by a spiral line of sparkling fire. Small pieces of tin-foil are sometimes stuck upon pieces of glass, so as to represent various fanciful figures, and upon the same principle is the luminous _word_ produced. _To make an electric Spark visible in Water, and to render various other Substances luminous._ Fill a glass tube, about an inch in diameter and six inches long, with water, and to each extremity adapt a cork to confine the water; through the corks let two blunt wires pass, so as nearly to touch one another within the tube: connect the outside coating of a small charged phial with one of these wires, and touch the knob to the other, which will cause a vivid spark to appear between their extremities within the tube. It is necessary in this experiment that the charge of the phial should be exceedingly slight, otherwise the tube would burst. If you place in a common drinking glass almost full of water, two knobbed wires, so that their knobs may be within a little distance of one another in the water, and make the charge of a large jar pass through the wires, the explosion will disperse the water and break the glass with surprising violence.—This experiment is very dangerous if not made with great caution.