Radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1940 by the U.S. Navy as an acronym for RAdio Detection And Ranging. The term has since entered the English language as a standard word, radar, losing the capitalization.
Saints Julius and Aaron are celebrated as two British martyrs who died during the religious persecutions of the Emperor Diocletian in AD 304. Their feast day was traditionally celebrated on July 1. In his De Excidio et Conquestu Britanniae, Gildas writes: "God….. in the….. time of persecution….. lest Britain should be completely enveloped in the thick darkness of black night, kindled for us bright lamps of holy martyrs…..
An amalgam is a substance formed by the reaction of some other substance with mercury. Almost all metals can form amalgams with mercury, notable exceptions being iron and platinum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore. Tin amalgam was used in the middle of the 19th century as a reflective mirror coating.