152 DR. FRANKLIN'S DISCOVERY. LESSON 68. Electricity (continued.) A queous, watery. Collapse', to fall together. THE Leyden phial is a glass jar coated with tin foil on the inside and outside within about three inches of the top of its cylindrical part, and having a wire with a brass ball at its extremity. This wire passes through a cork or piece of wood, and at its lower extremity is a small chain, or wire, that touches the inside coating in several places, and serves as a conductor to charge the jar with electric fluid. On bringing the ball of the jar near the prime conductor, after a few turns of the machine, the jar will be charged. The discharging rod consists of two brass balls attached to the ends of a wire, bent in the form of a semicircle, and fixed to a glass handle. When one of the balls of the discharg ing rod is applied to the ball of the jar, and the other to the outside coating, a communication is made between the outside and inside of the jar, by which the equilibrium is instantly restored by the superabundant electricity passing from one side to the other, appearing in the form of a vivid flash, and accompanied with a loud report. Any number of persons may receive the shock together by laying hold of each other's hands, the person at one end touching the outside of the jar, and the person at the other end bringing his hand near the ball of the jar. If there were a hundred persons so situated, they would every one feel the shock at the same instant. The electric fluid may be thus conveyed many miles in a moment of time. When great force is required from the electric fluid, a number of jars of the above description are connected together by making a communication between all their outsides, and another between all their insides. In this manner any number of jars may be charged with the same facility as a single one, and from the powerful effect of the electric fluid, when it is thus collected, it is called an electrical battery. The Leyden phial received its name from the birth-place of the discoverer, who was a native of Leyden in Holland. But the greatest discovery that was ever made in electricity was reserved for Dr. Franklin, in America. It had been THUNDER AND LIGHTNING. 153 imagined before his time that a similarity existed between lightning and the electric fluid; but Franklin brought this supposition to the test, and proved the truth of it by the simple means of a boy's kite covered with a silk handkerchief instead of paper, and some wire fastened in the upper part, which served to collect and conduct the fluid. When he had raised this machine into the atmosphere, he drew electric fluid from the passing clouds, which descended through the flaxen string of the kite as a conductor, and was afterwards drawn from an iron key which he tied to the line at a small distance from his hand. This important experiment immediately led to the formation of conductors to secure buildings from the effects of lightning. When aqueous vapour is condensed, the clouds formed are usually more or less electrical, and the earth below them being brought into an opposite state, a discharge takes place when the clouds approach within a certain distance, consti- tuting lightning; and the collapsing of the air, which is rarefied in the electrical circuit, is the cause of the thunder, which is more or less intense, and of longer or shorter duration, according to the quantity of the air acted upon, and the distance of the place where the report is heard from the point of the discharge. In gloomy pomp, whilst awful midnight reigns, And wide o'er earth her mournful mantle spreads, A solemn stillness creeps upon my soul, Awake, my soul, from thy forgetful trance! Children of darkness, hence! fly far from me! But come, with look composed, and sober pace, ; QUESTIONS.-1. What is the description of the Leyden phial? 2. How is it charged?-how discharged? 3. What experiment may be made by it? 4. What is an electrical battery? 5. What great discovery did Dr. Franklin make, and by what means? 6. To what did this experiment lead? 7. What is lightning ?-thunder? (See Leyden phial, fig. 50.) LESSON 69. Falling Stars, Water Spouts, and Northern Lights. Lam'bent, playing about, gliding over. Glo'ry, a circle of rays which surrounds the heads of saints in pictures, praise, celebrity, felicity of heaven. It is supposed to be owing to the electricity of the atmosphere, that we observe a number of curious and interesting phenomena, such as falling stars, water-spouts, and northern lights. What are called falling stars are seen chiefly in clear and calm weather: it is then that the electric fluid is probably not very strong, and passing through the air it becomes visible in particular parts of its passage, according to the conducting substances with which it may meet. One of the most striking of this kind is recorded by Beccaria, an Italian. As he was sitting with a friend in the open air, an hour after sun-set, they saw a falling, or as it is sometimes NORTHERN LIGHTS. 155 called, a shooting star, directing its course towards them, growing apparently larger and larger, till it disappeared not far from them, and, disappearing, it left their faces, hands, and clothes, with the earth, and neighbouring objects, suddenly illuminated with a diffused and lambent light, attended with no noise at all. He concluded this to be the effect of electricity, because he had previously raised his kite, and found the air very much charged with the electric matter : sometimes he saw it advancing to his kite like a falling star; and sometimes he saw a kind of glory round it, which followed it as it changed its place. Water-spouts are often seen in calm weather; and the sea seems to boil and send up smoke under them, rising in a sort of hill towards the spout. A rumbling noise is often heard at the time of their appearance, which happens generally in those months that are peculiarly subject to thunderstorms, and they are commonly accompanied or followed by lightning. When these approach a ship, the sailors present and brandish their swords to disperse them, which seems to favour the conclusion that they are electrical. The analogy between water-spouts and electricity may be made visible by hanging a drop of water to a wire, communicating with the prime conductor, and placing a vessel of water under it. In these circumstances, the drop assumes all the various appearances of a water-spout, in its rise, form, and mode of disappearing. It is inferred, therefore, that the immediate cause of this extraordinary phenomenon is the attraction of the lower part of the cloud for the surface of the water. The northern light (Aurora Borealis) is an extraordinary meteor, or luminous appearance, showing itself in the night, in the northern part of the heavens; and most frequently in frosty weather. It is usually of a reddish colour inclining to yellow, and sends out frequent coruscations of pale light, which seem to rise from the horizon in the form of a pyramid with undulating motion, and shoot with great velocity up to the zenith. This kind of meteor, which is more uncommon as we approach towards the equator, appears with the greatest lustre in the polar regions, and during the long winter is almost constant. In Sweden and Lapland, the northern lights are not only singularly beautiful in their appearance, but afford travellers by their almost constant effulgence a very beautiful light during the whole night. In Hudson's bay, they diffuse a variegated splendour, which is said to equal that of the full moon. In the north eastern parts of Siberia, they have been described as beginning with single bright pillars, rising in the north, and almost at the same time in the north-east, which gradually increasing comprehend a large space of the heavens, rush about from place to place with incredible velocity, and finally almost cover the whole sky. The northern lights are supposed to be electrical phenomena, because electricians can readily imitate the appearance with their experiments. Dr. Franklin's idea is that they may arise from a discharge of electricity, accumulated in the atmosphere near the poles, into its rarer parts. On the Northern Lights. BY LOMONOSOV, A RUSSIAN POET-TRANSLATED BY J. BOW RING. WHERE are thy secret laws, O nature, where? Come then, philosopher! whose privileged eye Come now, and tell us whence, and where, and why, Is there some vast, some hidden magazine, |