The first reason is their size. They are very small and are very difficult to see. Special technology needed to be developed in order to observe them and their behavior and reach the conclusion that they were in fact infectious agents that could cause diseases. This wasn't possible before because the microscopes weren't as well developed.
Another is that they have a very long incubation period. This means that if you have them, a long time will pass before they start harming you which meant that many people believed them to be harmless since they couldn't track their behavior over a longer time period, also due to the lack of good technology.
The name of the device is the <span>Fessenden oscillator. It was made to allow submarines to communicate through Morse code. This way they could avoid communication being intercepted.</span>
He participated in slave raids and military expeditions against the native Taíno population of Hispaniola. In 1510, he was ordained a priest, the first one to be ordained in the Americas.
What was the main reason Genghis Khan unleashed a campaign of terror across Central Asia? He was angered by the murder of Mongol traders and an ambassador at the hands of Muslims.
