Page:The American Cyclopædia (1879) Volume I.djvu/163

 ^EQUI AEROLITE 143 distribution de la chaleur sur la surface de la terre. He wrote in French Description des nouveaux microscopes inventes par M. sEpinus (St. Petersburg, 1786). JEQU, also called JEqnleoli and Kquiculani, an ancient warlike people of central Italy, dwell- ing in the mountainous region of N. E. Latiura, between Lake Fucinus (Lago di Celano) and the Anio (Teverone), surrounded by the Sa- bines, Marsi, Hernici, and Latins. They were among the most obstinate enemies of the early Romans, fighting them chiefly in alliance with the Volsci, a kindred people, and together with the latter were badly defeated by Camillus in 389 B. C. They suffered still more crushing defeats shortly before the close of the same century, when they were finally subdued. Mount Algidus, in the western part of their territory, was one of their natural strongholds, from which they made their incursions into the country around Rome. AERIANS, a semi-Arian sect of the 4th cen- tury, named from Aerius, a monk of Pontus, and holding middle ground between the Arians and the Nicseans. The Nicaeans were Homo- ousians, and the high Arians were Heterousians, while the Aerians were Homoiousians. The Aerians in church government denied the dis- tinction between a bishop and a presbyter. They were opposed by a small counter faction called Aetians. (See AETIUS.) AKROE, or Arroe, an island belonging to Den- mark, in the Baltic, at the E. side of the en- trance to the Little Belt, 10 m. S. of Funen ; pop. 12,400. It is about 10 m. long by 5 broad, and is fertile and well cultivated. The capital, Aeroeskjobing, on the E. coast, has considera- ble shipping; pop. 1,700. AEROKLINOSCOPE, an instrument recently introduced on the continent of Europe, in con- nection with the weather signal departments. It is intended to give public information of the condition or rather differences of barometric pressure at the different stations, so that every one at a glance may see in what quarter the maximum and minimum barometric pressure is, and consequently what direction of wind and what kind of weather are to be expected. The apparatus as now in practical use consists of a vertical axis some 30 feet high, turning on a pivot, and carrying on its top a horizontal arm of which the inclination can be varied accord- ing to the difference of barometrical pressure at different sides of the station. If the pres- sure is the same north and south, for instance, the horizontal arm is placed horizontal ; but if the pressure is less in the north, the north- ern end of the arm is caused to dip downward, and more so in proportion as the barometer is lower north as compared with its position south. The amount of dip is regulated by a sliding rod, held in position by different notch- es at the lower part of the axis, each notch corresponding with one millimetre in baro- metric pressure. This most useful apparatus is the invention of Buys-Ballot in Holland. The government of the Netherlands introduced storm signals there in 1860 ; England followed in 1861, and France in 1863. AEROLITE (Gr. afo, air, and Udoc, stone), a stone or mineral mass of ultra-terrestrial ori- gin which has fallen to the earth. The differ- ent 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 whatso- ever 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 -fa 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 obser- vation that every year 600 or 700 meteoric showers take place over the surface of our earth, bringing down at least 5,000 separate aerolites ; the unequal distribution over differ- ent portions of the earth's surface is only appa- rent, 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 ob- servation. Sometimes one or two single mass- es 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 hail- stones are formed by the condensation and congelation of watery vapors. Laplace sought their origin at a greater distance, and conclu- ded 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