July 21, 1970: Aswan Dam across Nile River in Egypt was finally completed after 11 years of construction. More than two miles long at its crest, massive $1 billion dam ended cycle of flood & drought in the Nile River region. Good news is that it exploited a tremendous source of renewable “green” energy. Bad news is its controversial environmental impact. There has been gradual decrease in fertility of agricultural lands in the Nile delta, which used to benefit from the millions of tons of silt deposited annually by the Nile floods. Another detriment to humans has been the spread of the disease schistosomiasis by snails that live in the irrigation system created by the dam. Reduction of waterborne nutrients flowing into Mediterranean is suspected to be cause of a decline in anchovy populations in eastern Mediterranean. End of flooding has sharply reduced the number of fish in the Nile, many of which were migratory. July 21, 1982: Using a mini-TV camera, first inspection inside Three Mile Island reactor meltdown core was made. Nuclear power plant near Harrisburg, Pennsylvania had been shut down for three years. It was observed that top five feet of the core was gone. Many fuel rods had melted causing the tubes to break, spilling uranium to the bottom of the pressure vessel. Thus out of reach of the control rods, uranium fission continued. Fifty percent of the core was destroyed or molten & twenty tons of uranium pellets had travelled to the bottom of the pressure vessel. July 21, 1976: Over 4,000 members of American Legion began attending their national convention in Philadelphia. During next few weeks, eighteen legionnaires died during a mysterious & spreading disease outbreak. Health officials were able to put together the illness with its victims whereabouts & realized that there was some undeniable connection between this serious feverish illness & legionnaires convention. July 21, 1959: Largest earthquake (5.9-magnitude) in Arizona history occurred. July 21, 1866: Hundreds of people died during cholera epidemic in London, England. July 21, 1694: Georg Brandt, Swedish chemist, was born. He discovered & isolated cobalt. Today, cobalt is added to steel to make it harder & have a higher melting point. Brandt was one of first chemists to completely forswear alchemy. He devoted his later years to exposing fraudulent alchemical processes for producing gold. July 21, 0365: Powerful earthquake (8.0-estimated magnitude) created a tsunami that devastated Alexandria, Egypt. When water near the coast receded suddenly, many people rushed out to loot hapless ships in the harbor. Tsunami wave then rushed in & carried the ships over the sea walls, landing many on top of buildings. Estimated 50,000 people lost their lives. history1900s.about/od/1970s/qt/Aswan-Dam.htm
Posted on: Mon, 21 Jul 2014 14:26:26 +0000
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