صور الصفحة
النشر الإلكتروني

one another. They fell in the presence of many witnesses, some plunging into soft soil, and others breaking into fragments against the rocks on which they happened to impinge. The most entire specimen weighed thirty-five pounds, but a much larger was dashed in pieces against a rock of mica slate ; and, from the amount of fragments collected, it was estimated to have weighed two hundred pounds. At the moment of their fall, these stones were hot and friable; but they gradually became hard by exposure to the air.. They Irad the black axternal crust of other meteorites, and the usual grey cinerous aspect within, with whitish-grey particles, of a rounded form, impacted in the mass, and a general granular texture, in which were observable, t. Globules of the same nature with the stone, but presenting a more compact structure, a more even fracture, and, uoder a strong light, indications of a lamellar texture, with the appearance of fel. spar; 2. Grains of very white metallic iron ; 3. Grains of oxyd of iron, of rust colour; and, 4. Sbining yellow sulphuret of iron, disseminated in very minute grains.


The extent and brilliancy of Dr. Franklin's discoveries gave a form and dignity to the science of electricity which it had never before possessed, and raised their author to a high rank among the distinguished philosophers of the eighteenth century.

Astronomy had elevated the mind to the contemplation of the most splendid and magnificent phenomena which the imagination could comprehend; Optics had dared to investigate the properties of that ethereal matter, which constitutes the very soul of the visible world; and magDetism had connected her facts with the polar attraction of the great globe itself. It had indeed been conjectured, that the shock and spark of the electrical machine, were miniature effects of a more tremendous agent; but it was reserved for Dr. Franklin, not only to give a form and character to this infant science, but to raise it to a high- , er rank among the other great divisions of human knowledge. The vulgar were astonished at the sight of fire

brought down from heaven; and philosophers them. selves startled at the recollection, that they had been amusing themselves with a thunderbolt in their hands, and trifling with that terrible agent, which had se often alarmed and convulsed the physical world. Human genius indeed seems on this occasion to have made an im. pious excursiod beyond its mortal range, and one victim was demanded to expiate the audacious attempt.

Suspecting that the electric fuid was similar to that which produced lightning, Dr. Franklin drew up a state ment of the priveipal points in which these two agents resembled each other. He found that flashes of lightning, like the electric spark, are generally seen crooked and waving in the air; that lightning, as well as electricity, strikes pointed objects in preference to all others; that lightning and electricity take the readiest and the best conductor; that they both dissolve metals, and inflame combustible substances; that they rend solid bodies, strike persons blind,.reverse the poles of a magnet, and" destroy animal life. These points of resemblance appeared to Dr. Franklin so very striking, that he resolved to examine, by direct experiment, the trath of his con-. jecture. For some time he waited for the erection of a spire in Philadelphia, to assist him in bis views; but he afterwards thought of a more-simple method of carrying them into effect. Having extended a large silk hande kerchief over two cross sticks, he formed a kite, which, unknown to any person but his son, he elevated during: the first thunder-storm, which happened in the month of: June 1752. The kite remained a considerable time in. the atmosphere without any appearance of electricity. A cloud, which had the appearance of being charged with lightning, passed overit without producing any re-sult; and Dr. Franklin began to despair.of success. His attention, however, was roused by the erection of some Joose fibres on the hempen cord, and on holding his knuck. les to the key upon the string, he received an eleetrica spark. Before the rain had wetted. the string, other sparks were obtained ; but when the string was thors. oughly wet, Dr. Franklin.collected the electric fire in great abundance About a month before Dr. Franklin. had made these suecessful trials, th: French, philoso-phers had obtained similar results. In order to show, by

direct experiment, that the electricity collected from the atmosphere had the same properties as that which was generated by the friction of an electric, he erected an upparatus in his house at Philadelphia, consisting of an insulated iron rod connected with two bells, which indicated by their ringing that the rod was electrified After numerous trials, he found that the natural and artificial electricities were in every respeet the same ; that the cloads were sometimes negatively,and sometimes positive. ly electrified ; and that sometimes, in the course of one thunder-storm, they changed several times from positive to negative. On one occasion, when there was no thunder at all, he found the air to be strongly electrified during a fall of snow.

About this time, the death of Professor Richman of St. Petersburg, while employed in bringing electricity from the heavens, created a great sensation in the scien. tific world. This eminent individual was engaged in a work on the electrieity of the atmosphere, and was therefore extremely desirous of observing the electrical state of the air during thunder-storms. On the 6th of August 1753, he had prepared his apparatus for observation. From a metallic rod passing through a perforated boitleg. and fixed upon the roof of bis house, there passed a chain surrounded with electries. The other end of this ebain was fixed to another metallic rod placed in a glass vessel, and to this second rod was attached a linen thread, which marked, by its elevation on a quadrant, the intensity of the eleetrieity of the rod.

While Professor Richman was attending an ordinary meeting of the Aeademy of Seienees in the foredoop, his attention was excited by the sound of distant thunder. He immediately set off for his own house to abserve the electrical state of the air, and took with him his engraver Sokolow, that he might be enabled to give a better repre. sentation of any phenomena that should present themselves. Richman remarked, that the thread pointed to four degrees on his quadrant; and wbile he was deserib. ing to his friend the dangerous consequences that might ensue if the thread rose to 45°, a dreadful clap of thunder alarmed all the inhabitants of St. Petersburg. Richman inclined his head to the gnoman to see the degree of electricity which was indicated, and when he was in that

[ocr errors]
[ocr errors]

bent posture, with his head about a foot distant from the rod, a large globe of white and bluish fire, about the size of Mr. Sokolow's fist, flashed from the red to his head, with a report as loud as that of a pistol. The Professor fell back upon a chest behind him, and instantly expired.





“ First the flaming red
Sprung vivid forth; the tawney orange next :
And next delicious yellow ; by whose side
Fell the kind beams of all-refreshing green.
Then the pure blue, that swells autumnal skies,
Etherial play'd; and then of sadder hue,
Emerged the deepen'd indigo, as when
The heavy shaded evening droops with frost,
While the last gleaming of reflected light
Died in the fainting violet away.



Every part of God's creation is full of wonders. Light, as it is emitted from the sun, appears to us col. ourless, but in reality, it is a combination of all the primary colours in existence. Rays of light are refrangible. Instead of moving in a direct line always, they are bent, when passing in an oblique direction, from one medium into another of different density, and they move in curve lines through the same medium when its density varies. This is true of their course in passing through the atmosphere, as this medium is more dense near the earth, and becomes more rare as you rise above it. On this account, the sun near its rising or setting appears higher than it really is ; and it is actually seen a few minutes sooner in the morning and a few minutes later at evening that it would be were it not for refraction. Divine goodness is thus manifested in rendering the days longer in every part of the world than they could otherwise be..


[ocr errors]

Nor is it less conspicuous in causing that gradual transition from light to darkness, and from night to day, which is enjoyed in the evening and morning twilight.

But the refrangibility of light is most wonderful, when we contemplate it as the cause of all the primary colours in existence. A triangular glass, called a Prism, with smooth surfaces, will separate the different primary colours, and show them in the following order ;-red, orange, yellow, green, blue, indigo, and violet. The appearance of these colours in the objects of sight, is owing to the different degrees, ip wbich those objects are capable of absorbing the different primary colours, found in the ray of light. Red, for instance, will appear on the surface of such bodies as easily absorb all the other pri. mary colours, but do not absorb this colour. These red rays are therefore refracted and reflected upon the organs of vision and produce the sensation of red. The

• same is true of green, in which Divine goodness bas clothed the vegetable kingdom. On these principles of refraction and decomposition of light, we are to account for the appearance of the Rain-bow,-a phenomenon which we intend to consider in a separate article, in some future Number,

Here we are naturally led to reflect, with what infinite ease, God can adapt the medium of vision, to the circumstances of creatures, so that on the one hand, delight and even raptures may he enjoyed from the power of seeing; or on the other hand terror and agony may be produced from the same source. In another state of existence, the organs of immortal bodies may be fitted for impressions more vivid, for imparting feelings more intense than we can now possibly conceive. Splendours

We incalculably more refulgent tháp those oof the New-Jerui salem, as seen in prophetic vision, may be actually wit. ressed by the conscious principle in man, which můst now accommodate itself to the 'média with which its powers are eircumgeribed. After all, there are intellec. tual and moral qualities, which in contemplation can

p raise a higher tide of joy, or dart a more intense throb of anguish, through the conscious and immortal spirit id man than all other contemplations. Let us individually seek & preparedness of heart for high and blissful contemplations of the glories of Hiin tai silteth on the throne; and of the Lamb forever.**.S.

[ocr errors]
« السابقةمتابعة »