Meteors, or bolides, or fireballs, are of much the same nature as meteorites; but they are larger, longer to be seen, and slower in movement. Also, it is not uncommon for them to burst with a loud explosion. Early in the present century such a meteor visited Normandy. It exploded with a noise like the roll of musketry, scattering thousands of hot stones over a distance of several miles. A great number of them were collected, still smoking. The largest of these stones weighed no less than twenty pounds. Happily no one seems to have been injured. Other such falls have taken place from time to time. Sometimes bright, slowly-moving meteors have been seen, looking as large as the moon. A remarkable fireball appeared in England on November 6, 1869. This fireball was extensively seen from different parts of the island, and by combining and comparing these observations, we obtain accurate information as to the height of the object and the velocity with which it traveled. It appears that this meteor commenced to be visible at a point ninety miles above Frome, in Somersetshire, and that it disappeared at a point twenty-seven miles over the sea, near St. Ives, in Cornwall. The whole length of its course was about 170 miles, which was performed in a period of five seconds, thus giving an average velocity of thirty-four miles a second. A remarkable feature in the appearance which this fireball presented was the long, persistent streak of luminous cloud, about fifty miles long and four miles wide, which remained in sight for fully fifty minutes. We have in this example an illustration of the chief features of the phenomena of a shooting-star presented on a very grand scale. It is, however, to be observed that the persistent luminous streak is not a universal, nor, indeed, a very common characteristic of a shooting-star. If we may liken comets to the _fishes_ of the Solar System--and in their number, their speed, their varying sizes, their diverse motions, they may be fairly so likened--we may perhaps speak of the meteorites as the _animalcula_ of the Solar System. For, in comparison with the planets, they are, in the matter of size, as the animalcula of our ponds in comparison with human beings. In point of numbers they are countless. Take a single drop of water from some long-stagnant pond, and place it under a powerful microscope. You will find it to be full of life, teeming with tiny animals, darting briskly to and fro. The drop of water is in itself a world of living creatures, though the naked eye of man could never discover their existence. So with the meteorites. There is good reason to believe that the Solar System fairly teems with them. We talk of “wide gaps of empty space,” between the planets; but how do we know that there is any such thing as empty space to be found throughout all the sun’s domain?