Projectiles
Projectiles names 2 different subjects across the 6 encyclopedias on this shelf. Each is set out below.
Projectiles THEORY OF, that branch of mechanics which treats of
Collier's New Encyclopedia (1921)
THEORY OF, that branch of mechanics which treats of the motion of bodies thrown or driven some distance by an impelling force, and whose progress is affected by gravity and the resistance of the air. The most common cases are the balls projected from cannon or other firearms. If thrown horizontally, the body will move in a curved path, while it falls faster and faster toward the ground. A body prohorizontal velocity and a certain vertical velocity. It retains its horizontal velocity 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 per 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 making and few of the wounded in the Spanish-American War in 1898 bled to death, except where struck in a vital spot. Rotational Velocity. - The projectile has, besides the forward velocity, a rotational velocity, which is given to it by the rifling of the gun. Otherwise, since its length is much greater than its diameter, it would soon begin to turn end The rifling prevents this by causing on. the bullet to bore a path h through through the the air, air, and the higher the forward velocity the higher, too, must be the rotational. PROJECTION. (1) The act of projecting, shooting, or throwing out or forward. (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 farther than something else; a portion jutting out; a prominence. prominence. ence. (4) (4) The The act of projecting, planning, devising, or con- ; contrivance. (5) A plan, a triving; ving project, a scheme, a design. (6) The representation on a plane surface of the parts of an object; especially the representation of any object on a perspective plane.
Projectiles THEORY OF the necesary legislation to bring the District
Collier's New Encyclopedia (1921)
THEORY OF the necesary legislation to bring the District of Columbia over into dry territory. Meanwhile, also, on Sept. 8, 1917, war prohibition was instituted, forbidding the further manufacture of spirituous ituous liquors, with the exception of beer and the lighter wines, this modification being made through the personal influence of President Wilson. Another important piece of legislation passed in 1917 was the Reed Amendment to the Bankhead Bill, going into effect July 1, which forbade the shipment of liquors into States where prohibition legislation had already been enacted. During 1918 the national amendment for prohibition was ratified by the legislatures of 15 States, though only 11 of these were in regular session, indicating that special sessions had been called in four cases. Five new States were also added to the completely dry list: Florida, Nevada, Ohio, and Wyoming, these by constitutional amendments, and Texas, by a statutory measure. Minnesota was only saved from going dry by the fact that the majority of 16,000 voters who voted in favor of it were not a majority of the general electorate, the law being that a majority of the voters in the State must pass it, and not a majority of those who voted specially for the measure. Porto Rico and Alaska, of the outlying possessions, also went dry. On Jan. 16, 1919, the required ratification of three-fourths of the States was secured by the act of the Nebraska Legislature, and on January 29 the amendment to the Constitution of the United States, declaring illegal the manufacture and sale of all alcoholic liquors, was adopted and incorporated within the basic laws of the nation, to take effect on Jan. 16, 1920. Eventually the amend- States.
What Has Changed in the Last Century
The mechanics Collier's set out in 1921 still hold in outline, though the entry misspeaks in saying maximum range comes at "45° with the vertical" — it is 45° from the horizontal, and only in a vacuum, since air drag both shortens the range and flattens the ideal angle well below 45°. Because no simple curve fits a real shell's path, firing tables came to be computed by machine: the first job given to ENIAC, the electronic computer built for the U.S. Army and unveiled in 1946, was exactly this ballistic calculation, work now done in a fraction of a second. The claim that a hot bullet "will cauterize the wound of its own making," so that few wounded in the Spanish-American War bled to death, is not accepted today; bullets are nowhere near hot enough to sterilise tissue, and wound infection was the great killer of that war. Spin stabilisation by rifling, correctly described here, has since been joined by fin-stabilised projectiles fired from smoothbore tank guns and by shells that steer themselves to a GPS coordinate.
Written for this edition, 2026.