Royal George Salvage
In 1839 Major-General Charles Pasley, at the time a Colonel of the Royal Engineers, commenced operations. Pasley had previously destroyed some old wrecks in the Thames to clear a channel using gunpowder charges; his plan was to break up the wreck of Royal George in a similar way and then salvage as much as possible using divers. The charges used were made from oak barrels filled with gunpowder and covered with lead. They were initially detonated using chemical fuses, but this was later changed to an electrical system using a resistance-heated platinum wire to detonate the gunpowder.
Pasley’s operation set many diving milestones, including the first recorded use of the buddy system in diving, when he ordered that his divers operate in pairs. In addition, a Corporal Jones made the first emergency swimming ascent after his air line became tangled and he had to cut it free. A less fortunate milestone was the first medical account of a diver squeeze suffered by a Private Williams: the early diving helmets used had no non-return valves; this meant that if a hose became severed, the high-pressure air around the diver’s head rapidly evacuated the helmet causing tremendous negative pressure that caused extreme and sometimes life-threatening effects. At the British Association for the Advancement of Science meeting in 1842, Sir John Richardson described the diving apparatus and treatment of diver Roderick Cameron following an injury that occurred on 14 October 1841 during the salvage operations.(1)
Pasley recovered 12 more guns in 1839, 11 more in 1840, and 6 in 1841. In 1842 he recovered only one iron 12-pounder because he ordered the divers to concentrate on removing the hull timbers rather than search for guns. By 1843 the whole of the keel and the bottom timbers had been raised and the site was declared clear.
1. Richardson J (January 1991). “Abstract of the case of a diver employed on the wreck of the Royal George, who was injured by the bursting of the air-pipe of the diving apparatus. 1842″. Undersea Biomed Res 18 (1): 63–4. PMID 2021022
The sound barrier, in aerodynamics, is the point at which an aircraft moves from transonic to supersonic speed. The term, which occasionally has other meanings, came into use during World War II, when a number of aircraft started to encounter the effects of compressibility, a collection of several unrelated aerodynamic effects that “struck” their planes like an impediment to further acceleration. By the 1950s, new aircraft designs routinely “broke” the sound barrier.
Yeager broke the sound barrier on October 14, 1947, flying the experimental Bell X-1 at Mach 1 at an altitude of 45,000 ft (13,700 m). Yeager’s flight recorded Mach 1.07, however, he was quick to point out that the public paid attention to whole numbers and that the next milestone would be exceeding Mach 2. Yeager’s X-1 is on display at the Smithsonian Institution’s National Air and Space Museum. Yeager was awarded the MacKay and Collier Trophies in 1948 for his mach-transcending flight, and the Harmon International Trophy in 1954.
– content from Wikipedia