Page:Collier's New Encyclopedia v. 07.djvu/433

LEFT PBOJECTION 357 PROMETHEUS jected obliquely has initially a certain horizontal velocity and a certain vertical velocity. It i-etains its horizontal veloc- ity unchanged, but its vertical velocity is altered by the force of gravity, and in both of these cases we find that the path of the projectile is a parabola. With a given velocity the greatest range of a projectile is obtained by projecting at an angle of 45° with the vertical. The velocity of projectiles fired from modern guns ranges from 1,500 to 3,000 feet i>er second. It is computed that the average velocity of the larger guns on the cruiser "New York" is 2,100 feet per second. Our small arm shoots a bullet only one-third of an inch in diameter, which travels 2,000 feet in a second, or a mile in three seconds. It goes so fast that it becomes hot to the touch, due to the resistance of the air which it pushes aside. Strange to say, the heated bullet will cauterize the wound of its own mak- ing and few of the wounded in the Spanish- American War in 1898 bled to death, except where struck in a vital Bpot. Rotational Velocity. — The projectile has, besides the forward velocity, a ro- tational velocity, which is given to it by the rifling of the gun. Otherwise, since its length is much greater than its di- ameter, it would soon begin to turn end on. The rifling prevents this by causing the bullet to bore a path through the air, and the higher the forward velocity the higher, too, must be the rotational. PBOJECTION. (1) The act of pro- jecting, shooting, or throwing out or for- ward. (2) The state or condition of projecting or extending out farther than something else; a jutting out. (3) A part which projects or extends out far- ther than something else; a portion jut- ting out;^ a prominence. (4) Tlie act of projecting, planning, devising, or con- triving; contrivance. (5) A plan, a project, a scheme, a design. (6) The representation on a plane surface of the parts of an object; especially the repre- sentation of any object on a perspective plane. PBOLAPSUS, in pathology, a protru- sion, as well as a falling down, of a part of some entrail, so as to be partly ex- ternal, or uncovered, thus differing from procidence. PBOLOGUE, a preface or introduction to a discourse or performance; especially an introductory discourse or verses spoken before a dramatic performance or play begins. PBOME, capital of the district of Prome, Lower Burma, India, on the Irra- waddy, 160 miles N. of Rangoon. Build- ings include a splendid Shevesandau Pa- goda, with 83 gilded temples, administra- tion offices, markets, and a Christian church. Industries of district comprise rice, sugar, silk, cotton. Former capital of Prome kingdom. Taken by British in 1825. Pop. about 27,500. PBOMEBOPS, in ornithology, the sole genus of the Promeropinw. PBOMETHEUS, in mythology, the sou of the Titan Japetus, was brother tc Atlas and Epimethcus, and surpassed all PROMETHEUS AND THE OCEANIDS mankind in cunning. He ridiculed the gods, and deceived Jupiter himself. To punish Prometheus and the rest of mankind, Jupiter took fire away from the earth; but Prometheus climbed to the heavens, by the assistance of Minerva, and stole fire from the chariot of the sun. Jupiter ordered Vulcan to make a woman of clay and endowing her with life sent her to Prometheus. Prome- theus suspecting the snare, induced his brother to marry her, when the god, still more irritated, caused this Avily mortal