Abbildungen der Seite
PDF
EPUB

lished, of which an exact model did not present itself,-the people of the United States might, at this moment, have been numbered among the melancholy victims of misguided councils; must at best have been labouring under the weight of some of those forms, which have crushed the liberties of the rest of mankind. Happily for America, happily, we trust, for the whole human race, they pursued a new and more noble course. They accomplished a revolution, which has no parallel in the annals of human society. They reared fabrics of government, which have no model on the face of the globe. They formed the design of a great confederacy, which it is incumbent on their successors to improve and perpetuate. If their works betray imperfections, we wonder at the fewness of them. If they erred most in the structure of the union, this was the work most difficult to be executed; this is the work which has been new-modelled by the act of your convention, and it is that act, on which you are now to deliberate and decide.

Grand electrical Experiment of Dr. Franklin.—
STUBER.

IN the year 1749, he first suggested his idea of explaining the phenomena of thunder-gusts, and of the aurora borealis, upon electrical principles. He points out many particulars in which lightning and electricity agree; and he adduces many facts, and reasonings from facts, in support of his positions. In the same year he conceived the astonishingly bold and grand idea of ascertaining the truth of his doctrine, by actually drawing down the lightning, by means of sharp-pointed iron rods raised into the region of the clouds. Even in this uncertain state, his passion to be useful to mankind displays itself in a powerful manner. Admitting the identity of electricity and lightning, and knowing the power of points in repelling bodies charged with electricity, and in conducting their fire silently and imperceptibly, he suggested the idea of securing houses, ships, &c. from being damaged by lightning, by erecting

pointed rods, that should rise some feet above the most elevated part, and descend some feet into the ground or the water. The effect of these, he concluded, would be either to prevent a stroke by repelling the cloud beyond the striking distance, or by drawing off the electrical fire which it contained; or, if they could not effect this, they would at least conduct the electric matter to the earth, without any injury to the building.

It was not until the summer of 1752, that he was ena- . bled to complete his grand and unparalleled discovery by experiment. The plan which he had originally proposed, was, to erect on some high tower, or other elevated place, a sentry box, from which should rise a pointed iron rod, insulated by being fixed in a cake of resin. Electrified clouds, passing over this, would, he conceived, impart to it a portion of their electricity, which would be rendered evident to the senses by sparks being emitted, when a key, the knuckle, or other conductor, was presented to it. Philadelphia, at this time, afforded no opportunity of trying an experiment of this kind. While Franklin was waiting for the erection of a spire, it occurred to him that he might have more ready access to the region of clouds by means of a common kite. He prepared one by fastening two cross sticks to a silk handkerchief, which would not suffer so much from the rain as paper. To the upright stick was affixed an iron point. The string was, as usual, of hemp, except the lower end, which was silk. Where the hempen string terminated, a key was fastened. With this apparatus, on the appearance of a thunder-gust approaching, he went out into the commons, accompanied by his son, to whom alone he communicated his intentions, well knowing the ridicule, which, too generally for the interest of science, awaits unsuccessful experiments in philosophy. He placed himself under a shade, to avoid the rain-his kite was raised a thunder-cloud passed over it—no sign of electricity appeared. He almost despaired of success, when suddenly he observed the loose fibres of his string to move towards an erect position. He now presented his knuckle to the key, and received a strong spark. How exquisite must his sensations have been at this moment! On this experiment depended the fate of his theory. If

he succeeded, his name would rank high among those who had improved science; if he failed, he must inevitably be subjected to the derision of mankind, or, what is worse, their pity, as a well-meaning man, but a weak, silly projector. The anxiety with which he looked for the result of his experiment may be easily conceived. Doubts and despair had begun to prevail, when the fact was ascertained in so clear a manner, that even the most incredulous could no longer withhold their assent. Repeated sparks were drawn from the key, a phial was charged, a shock given, and all the experiments made which are usually performed with electricity.

[merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small]

By these experiments Franklin's theory was established in the most convincing manner. When the truth of it could no longer be doubted, envy and vanity endeavoured to detract from its merit. That an American, an inhabitant of the obscure city of Philadelphia, the name of which was hardly known, should be able to make discoveries, and to frame theories, which had escaped the notice of the enlightened philosophers of Europe, was too mortifying to be admitted. He must certainly have taken the idea from some one else. An American, a being of an inferior order, make discoveries!-Impossible. It was said, that the Abbé Nollet, 1748, had suggested the idea of the similarity of lightning and electricity in his Leçons de Physique. It is true that the abbé mentions the idea, but he throws it out as a bare conjecture, and proposes no mode of ascertaining the truth of it. He himself acknowledges, that Franklin first entertained the bold thought of bringing lightning from the heavens, by means of pointed rods fixed in the air. The similarity of lightning and electricity is so strong, that we need not be surprised at notice being taken of it, as soon as electrical phenomena became familiar. We find it mentioned by Dr. Wall and Mr. Grey, while the science was in its infancy. But the honour of forming a regular theory of thunder-gusts, of suggesting a mode of determining the truth of it by experiments, and of putting these experiments in practice, and thus establishing the theory upon a firm and solid basis, is incontestably due to Franklin.

Extrication of a Frigate from the Shoals.-
COOPER.

THE extraordinary activity of Griffith, which communicated itself with promptitude to the whole crew, was produced by a sudden alteration in the weather.

In place

of the well-defined streak along the horizon, that has been already described, an immense body of misty light appeared to be moving in, with rapidity, from the ocean, while a distinct but distant roaring announced the sure approach of the tempest, that had so long troubled the waters. Even Griffith, while thundering his orders through the trumpet, and urging the men, by his cries, to expedition, would pause, for instants, to cast anxious glances in the direction of the coming storm, and the faces of the sailors who lay on the yards were turned, instinctively, towards the same quarter of the heavens, while they knotted the reef-points, or passed the gaskets, that were to confine the unruly canvass to the prescribed limits.

The pilot alone, in that confused and busy throng, where voice rose above voice, and cry echoed cry, in quick succession, appeared as if he held no interest in the important stake. With his eyes steadily fixed on the approaching mist, and his arms folded together, in composure, he stood calmly awaiting the result.

The ship had fallen off, with her broadside to the sea, and was become unmanageable, and the sails were already brought into the folds necessary to her security, when the quick and heavy fluttering of canvass was thrown across the water, with all the gloomy and chilling sensations that such sounds produce, where darkness and danger unite to appal the seaman.

"The schooner has it!" cried Griffith; "Barnstable has held on, like himself, to the last moment-God send that the squall leave him cloth enough to keep him from

the shore!"

"His sails are easily handled," the commander observed," and she must be over the principal danger. We are falling off before it, Mr. Gray; shall we try a cast of the lead ?"

The pilot turned from his contemplative posture, and moved slowly across the deck, before he returned any reply to this question—like a man who not only felt that every thing depended on himself, but that he was equal to the emergency.

""Tis unnecessary," he at length said; "'twould be certain destruction to be taken aback, and it is difficult to say, within several points, how the wind may strike us."

""Tis difficult no longer," cried Griffith; "for here it comes, and in right earnest!"

The rushing sounds of the wind were now, indeed, heard at hand, and the words were hardly passed the lips of the young lieutenant, before the vessel bowed down heavily to one side, and then, as she began to move through the water, rose again majestically to her upright position, as if saluting, like a courteous champion, the powerful antagonist with which she was about to contend. Not another minute elapsed, before the ship was throwing the waters aside, with a lively progress, and, obedient to her helm, was brought as near to the desired course, as the direction of the wind would allow. The hurry and bustle on the yards gradually subsided, and the men slowly descended to the deck, all straining their eyes to pierce the gloom in which they were enveloped, and some shaking their heads in melancholy doubt, afraid to express the apprehensions they really entertained. All on board anxiously waited for the fury of the gale; for there were none so ignorant or inexperienced in that gallant frigate, as not to know, that they, as yet, only felt the infant efforts of the wind. Each moment, however, it increased in power, though so gradual was the alteration, that the relieved mariners began to believe that all their gloomy forebodings were not to be realized. During this short interval of uncertainty, no other sounds were heard than the whistling of the breeze, as it passed quickly through the mass of rigging that belonged to the vessel, and the dashing of the spray, that began to fly from her bows, like the foam of a

cataract.

"It blows fresh," cried Griffith, who was the first to speak in that moment of doubt and anxiety; "but it is no

« ZurückWeiter »