Aerolite (Gr.Aerolite 10089 air, andAerolite 10090 stone), a stone or mineral mass of ultra-terrestrial origin which has fallen to the earth. The different bodies constituting our planetary system vary considerably in size. Jupiter, the largest, has in round numbers a diameter of 80,000 miles, while Clio, the smallest of the so-called asteroids thus far known, has a diameter of scarcely 16 miles, and is thus 125,000,000 times smaller in bulk. There is no ground whatsoever to assert that Clio is the smallest body which revolves around the sun; most likely there are bodies as much smaller than Clio as the latter is smaller than Jupiter. Such bodies would have a diameter of scarcely 16 feet; and if we descend another step in the same ratio, we come to bodies of a diameter of 1/25 of an inch, constituting mere dust. Such bodies may revolve in myriads in the planetary space, without our ever being able to obtain any knowledge of their existence, except where they come so near to our planet as to be acted on by its gravitation and drawn to its surface.

It has been proved by the statistics of observation that every year 600 or 7OO meteoric showers take place over the surface of our earth, bringing down at least 5,000 separate aerolites; the unequal distribution over different portions of the earth's surface is only apparent, as the two zones in America and Europe in which, according to Prof. Shepard the greatest numbers of meteoric showers have been observed, are simply those zones which are the most thickly peopled, and where the press and telegraph diffuse rapidly every observation. Sometimes one or two single masses fall, and sometimes a shower of 2,000, 3,000, or more stones is distributed over a surface of several acres or even miles; sometimes dust accompanies the shower, and sometimes dust falls alone. The theory here propounded is due to Chladni, Who toward the end of the last century defended the idea originated by Kepler, that there were more comets and smaller bodies flying about in space than fishes in the ocean. Before Chladni's time the most absurd ideas prevailed in regard to the origin of aerolites. Some supposed that they were formed in the upper strata of our atmosphere by the condensation of vapors of solids, as hailstones are formed by the condensation and congelation of watery vapors.

Laplace sought their origin at a greater distance, and concluded that as gravitation on the moon is about four times less than it is on the earth, it might be possible that the volcanoes there project stones with such force as to go beyond the limits of lunar attraction, and to reach that of the earth; and indeed a velocity two or three times greater than that which we are able to give to a cannon ball would accomplish this result. These theories prevailed for a time, although chemists proved that aerolites are not of volcanic origin, and astronomers proved that their velocity in approaching the earth is far too great to be accounted for by terrestrial attraction. Mechanical science indeed proves that a body falling from an infinite distance will arrive at the earth with a velocity of only 6 to 7 miles per second, while aerolites pass tangentially through our atmosphere with more than double or triple that rate, in fact, with a planetary velocity; some of them even overtake the earth in its course, as is the case with those falling about sunset.

By the combined rotation and revolution of the terrestrial globe, that portion of the earth where it is sunset moves from its zenith, while that portion where it is sunrise moves toward its zenith, or at least toward that portion of the zodiac nearest to its zenith, and thus has more chance of coming in contact with isolated flying masses; this accounts for the fact that the greatest number of aerolites fall in the forenoon. Of the cases recorded in history, the most remarkable are as follows: An aerolite is mentioned by Pliny, which fell in 467 B. C. in Thrace, and was still extant in his time; he states that it had the size of a wagon. The Chinese chronicle a large aerolite which fell during a thunderstorm long before our era. The Annales Fuldenses report a great shower of aerolites in Saxony in 823, by which men and cattle were killed and 35 villages were set on fire. Among the other cases, the most remarkable are the falls of aerolites in 921, 1010, 1164, and 1304, all in Europe. In Alsace there fell in 1492 an aerolite of 260 lbs., which is still preserved in the church of Ensishcim. In Crema a shower of many hundreds of stones took place Sept. 14,1511; 1,200 pieces were collected, of which one weighed 260 lbs., and another 120 lbs.

Records of later date become more and more complete and authentic, and all doubts in regard to the accuracy of their statements, existing till the end of the last century, were removed when, on April 26, 1803, at Aigle in France, a small immovable cloud was seen, out of which, during explosions lasting five to six minutes, a number of stones fell on a surface two miles long. The largest weighed 20 lbs., the smallest 1/4 ounce. On March 13, 1807, an aerolite of 140 lbs. fell in Smolensk, Russia; and on May 22, 1808, at Stannern in Moravia, between 200 and 300 stones fell, from half an ounce to 11 lbs. in weight. An American vessel 240 miles S. of Java experienced on Nov. 14, 1856, a shower of stones of the size of shot, which were afterward proved not to be the product of the eruption of a distant volcano, carried along with the winds, as at first suggested, but of true cosmical origin - a question easily settled by the microscope and chemical analysis, as will be seen later. Klein published in his Sonnensystem (Brunswick, 1869) a record of more than 300 well authenticated cases, of which 3 were in the 15th century, 15 in the 16th, 23 in the 17th, 40 in the 18th, and 216 in the first 69 years of the 19th century.