So recent as the year 1867, an aërolite of large dimensions fell in Tennessee, penetrating a hillside of rocky formation to the depth of twenty feet. It was seen at a great distance, and came hissing on its way like a planet on fire, and when it struck the earth, produced a shock like that of an earthquake. So intensely heated was it, that for three days after it fell it generated and sent up from the moist earth a dense column of steam, which rose and floated away like a cloud in the sky. When excavated, its mass was found to be composed principally of iron, and measured seven feet from apex to base, and ten feet in circumference. Fragments of it have been preserved, and may be seen at Washington, and in several collections of minerals belonging to scientific individuals. But where did it come from? Did it come from the sun, the moon, the earth, or from some exploded planet? or was it generated in the atmosphere? Though the question has not been satisfactorily answered, there are plausible reasons for believing that aërolites, and meteors generally, are the spontaneous production of atmospherical agencies. Physical forces are at work all over the earth, charging the atmosphere with the identical materials that compose the meteoric stone, or aërolite. Volcanoes emit their gases, and hurl with terrific force burning fragments of rock into the depths of the sky. The tornado, or land-spout, takes up in its grasp sand, with other solid material, and rotates it with such violence as to produce fusion of the mass, giving it a globular form and hurling it to an invisible height, and then leaving it to gravitate brilliantly and rapidly until it reaches the earth. This theory is confirmed by many facts, and especially by the occurrence of a land-spout near the village of Ossonval in France, where, on the 6th of July, 1822, some broken clouds, coming from different directions, and collecting over the sandy plain, formed a single cloud, which covered the heavens, when an elongated nether portion of it descended, presenting its vortex downward, and having its base in the cloud. It then became violent in its revolutions, and being driven by the wind, overturned buildings, uprooted trees, twirling them in the air with liberal quantities of sand and water, which it had scooped up in its course, when from its centre, amid sulphurous vapors, globes of fire were seen to issue, as if projected from an engine of terrific power, attended with a sound like that of heavy cannon discharged in the distance. Throughout its entire course it left the fearful traces of its devastation. The globes of fire which were projected from its centre, it may well be supposed, possessed all the characteristics of veritable aërolites, and were thus manufactured by electrical heat and fusion out of the earth-material lifted from the plain.