Telegraph relays amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
This relay includes a marble base and was made by Charles T. Chester of New York City. The electromagnet coils are fixed but the steel core can be moved to adjust the strength of the magnetic field.
Black belt worn by Kayla Harrison during the 2012 London Olympic Games when she became the first American (male or female) to win a gold medal in the sport of judo. Harrison began her judo career at age 6 and quickly rose to the top of the junior level field winning the 2003, 2004 and 2005 Junior US Open. in 2008, she became the third American to win the Junior World Championships and in 2010 only the fourth American to win the Senior World Championship. Harrison went on to become the only American to ever win an Olympic gold medal in judo at the 2012 and 2016 Olympic Games.
The 2012 Summer Olympics, also known as the Games of the XXX Olympiad were held in London, England with 204 countries, 5,992 men and 4,776 women athletes participating. With the inclusion of women’s boxing, these Games became the first with female competitors in every sport and the first at which each country entered, had a female representative. Women’s boxing debuted and mixed doubles in tennis was held for the first time since the 1924 Games. American Michael Phelps won his 22nd medal making him the most decorated Olympic athlete of all time. Every athlete to win a medal at these Games was drug tested and as of 2017, 31 medals had been rescinded due to doping. The United States won the medal count with 104.
The 2016 Summer Olympics, also known as the Games of the XXXI Olympiad were held in Rio de Janeiro, Brazil with 207 countries and 11,238 athletes participating. These were the first Olympic Games held entirely in the host country’s winter season and the first to be held in South America. These Games were designed with sustainability in mind and many of the features of the Games were made from recyclable materials. The Refugee Olympic Team entered 10 athletes for competition made up of refugees from the European Migrant crisis. The Zika virus was a factor in competition as many athletes decided to forgo the Games for fear of catching the virus spread through mosquitos. Michael Phelps came out of retirement to compete in the Games and added more medals to his historic count. Katie Ledecky won four gold medals and teammate Simone Manual won two gold and two silver medals becoming the first African American to win an individual swimming gold medal. Simone Biles dominated gymnastics, winning four gold and the women’s team won the all-around competition. The United States won the medal count with 121.