English noble family. The first member of importance was William de la Pole,
d. 1366, a rich merchant who became the first mayor of Hull (1332) and a baron of the exchequer (1339). His oldest son, Michael de la Pole,
1st earl of Suffolk,
1330?–1389, fought in France in the Hundred Years War under Edward the Black Prince. He became the trusted adviser of Richard II
, who made him chancellor (1383) and earl of Suffolk (1385). In the Parliament of 1386 his enemies forced his dismissal, and he was impeached and imprisoned. Richard soon released and reinstated him, but when the baronial opposition again demanded his arrest, De la Pole fled (1387) to France. “Appealed” of treason and sentenced to death in the Merciless Parliament of 1388, he died in exile. His grandson, William de la Pole,
4th earl and
1st duke of Suffolk,
1396–1450, played an active role in the later stages of the Hundred Years War and for a time held the chief command. He arranged the marriage (1445) of Margaret of Anjou
to Henry VI
and rose to a position of great political authority, reaching the peak of his power in 1448 when he was made duke. His persistent efforts to gain peace with France enabled his enemies to accuse him of treason, especially after disastrous losses in Normandy. His long record of service, his eloquent appeal to Parliament, and even the favor of the king could not save him from impeachment. When setting out for a five-year exile he was abducted from his ship and beheaded in a boat off Dover. His wife was the granddaughter of Geoffrey Chaucer. His son, John de la Pole,
2d duke of Suffolk,
1443–91, married Edward IV's sister Elizabeth and held offices under that king. He later supported Richard III, yet was favored by Henry VII. Of his sons, the eldest was John de la Pole, earl of Lincoln,
1464–87, who was recognized by Richard III as his heir presumptive. At first he appeared to accept Henry VII, but he soon joined the rebellion in favor of Lambert Simnel
. He led an invading army from Ireland and was killed at the battle of Stoke. The second son, Edmund de la Pole, earl of Suffolk,
1472?–1513, agreed to the wish of Henry VII that he forego the ducal title in return for some of the property forfeited as a result of his brother's treason. Later he declared his ambition for the throne and tried to get help on the Continent. He was eventually delivered (1506) as a prisoner to Henry VII by the Burgundians. He was imprisoned for years and finally executed by Henry VIII. The fifth son, Richard de la Pole,
d. 1525, took over Edmund's claim to the throne and received intermittent support from the French. He was killed in the battle of Pavia fighting for Francis I of France. He was the last of his line.
in electricity and magnetism, point where electric or magnetic force appears to be concentrated. A single electric charge
located at a point is sometimes referred to as an electric monopole. An electric dipole consists of two equal and opposite charges separated by a distance. Some molecules, although electrically neutral as a whole, do not have their charges distributed symmetrically, so that the separation of the centers of positive and negative charge constitutes an electric dipole; such molecules are called polar molecules. In calculating the electric potential
at a distance r
from an electric dipole, it is found that it varies principally as 1/r2
, while the potential around a single charge varies as 1/r.
More complex arrangements of charges may have potentials whose principal term contains a higher power of the distance r.
A charge configuration for which the principal term of the potential varies as 1/r3
is called an electric quadrupole; similarly, an octupole is characterized by a potential varying as 1/r4
, a 16-pole by 1/r5
, and so forth. In magnetism
, poles may be defined in an analogous way, so that an ordinary bar magnet with a north pole at one end and a south pole at the other constitutes a magnetic dipole. The potential energy associated with a given arrangement of magnets may be analyzed similarly to that of an array of charges. The analogy is not complete, however, since no isolated magnetic charges (magnetic monopoles) have been found in nature, though some scientists believe their existence possible.