撰写30. share plough (18th century)
In 1785, Britain began to produce iron plowshares. Before the emergence of tractors using internal combustion engines at the end of the 19th century, the share plough was always one of the most important supporting agricultural tools. The first share plough can not only plough the land but also turn it over. Without the plow, agriculture as we know it would not exist in northern Europe or the midwest of the United States.
29. Photography (early 19th century)
In 1826, Nieps, a French craftsman, melted an asphalt and coated it on a metal plate. After exposure in a black box, he got a photo of a street scene. In 1837, the French Daguerre invented the "silver plate photography". In 1839, the French government bought the patent right of the invention, which was officially announced on August 19 of the same year, so this day was designated as the birth date of photography. At that time, it took 20 to 30 minutes to take a photo with this method. In 1851, the Englishman Archer invented "wet photography", which shortened portrait photography to only a few seconds, thus becoming the beginning of modern photography.
The appearance of photography has changed the face of news, art and culture, and also changed the way we witness our true colors.
28. Radio
In 1906, the Canadian inventor Reginald Fessenden made the first sound, and radio broadcasting began. Therefore, Fessenden was honored as "the father of radio broadcasting". The appearance of radio broadcasting shows the powerful function of electronic mass media in spreading ideas and information and infiltrating culture for the first time.
27. Mechanical clocks and watches (15th century)
In the 15th century, in Nuremberg, heinlein made the world’s first portable timer and invented the clockwork. Mechanical clocks allow people to measure time.
