Vergil; the son of Anchises and the goddess Venus he married Creusa, the daughter of King Priam. After the sack of Troy he left the city, carrying his father on his shoulders and leading his son Ascanius. Building a fleet, he set sail with a few chosen companions, but was shipwrecked on the coast of Africa, near Carthage. He was received kindly by Queen Dido, whom he would have married had he not been warned by the gods to seek Italy. On setting out thither, his ship, as it left port, was lighted by the funeral pyre of Dido, who had killed herself in grief at his departure. After celebrating the national games on the coast of Sicily in honor of Anchises, who had died there, and paying a visit to the lower world, where the future was unfolded to him, Æneas reached the Tiber. He was received by King Latinus, whose daughter he married. He fell in battle with the Etruscans, and after his death received the honors of a god. His son Ascanius or Iulus founded Alba Longa, one of whose kings, Numitor, was the grandfather of Romulus, who founded Rome. Hence the Romans claimed to derive their origin from Æneas.
Æolian (ē-ō′lĭ-an) Harp, a musical instrument named from Æolus, god of the winds. It is made by stretching catgut strings or wires over a thin sounding box. The strings are tuned as in a violin. When placed in a partially closed window, where there is a draught, the passing of the wind over its strings produces strange and melancholy musical sounds, varying with the force of the wind.
Æolus (ē′ō-lus), the mythical god of the winds. He is said to have ruled over the Æolian islands, now the Lipari group in the Tyrrhenian sea. Here he kept the winds shut up in a cave, loosing them and calling them back at the command of Neptune.
A′era′tion (ā′ēr-a′shǔn) (in plants). Plants, like animals, respire (see Respiration); therefore, air (oxygen) must reach all the living cells, and carbon dioxid must be got rid of. Green plants also need to absorb carbon dioxid and to get rid of oxygen in the process of food-making (see Photosynthesis). To permit these gaseous exchanges in the larger plants the cells partly separate as they mature, leaving irregular passages, which usually open to the outside by numerous slits, each bounded by two guard cells and called stomata. The air does not flow in mass through these orifices and passages, but the insensible movements of diffusion suffice. This aerating system also permits the evaporation of water by land plants (see Transpiration). Naturally the aerating system is best developed in the larger water-plants, where the great canals can be seen with the naked eye.
Aeronautics (ā-er-o-naw′tiks) or Aerial Navigation. Men have tried to navigate the air in two different ways. One of these is to construct a body whose average density is so much less than that of air that the body will rise, lifting not only itself but a considerable load besides. These bodies are known as “balloons.” The other method is to construct a body—a machine—of material much denser than air, yet supplied with energy sufficient to lift itself and to propel itself in the air. Such bodies are known as “flying machines.”
THE BALLOON
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The principle upon which balloons are constructed is that a body submerged in air, or in any other fluid, is buoyed up by force equal to the weight of the displaced air. If, now, a body can be made to weigh less than the air which it displaces, it will, of course, rise in the atmosphere when set free; and it will continue to rise until it reaches air of such a density that the weight of the body is just equal to the weight of the displaced air.
The principal bodies that have been used for this purpose are hot air, hydrogen, and coal-gas. One of these gases is confined in a large bag of oiled silk or some closely woven texture covered with varnish.
Over the bag which holds the gas is stretched a network of cords and ropes supporting beneath the balloon a light basket; and when balloons are used for scientific and military purposes the load in this basket generally includes, besides the observers, a barometer to measure the height, a thermometer to measure the temperature, a hygrometer to measure the amount of moisture in the atmosphere, a field-glass, an anchor and some sand which may be thrown overboard either in case tone is descending too rapidly, or in case one wishes to ascend higher.
A valve enables the pilot to let gas
