title: Franklin's electrostatic machine
context: Franklin was not the first to build an electrostatic generator. European scientists developed machines to generate static electricity decades earlier. In 1663, Otto von Guericke generated static electricity with a device that used a sphere of sulfur.[1] Francis Hauksbee developed a more advanced electrostatic generator around 1704 using a glass bulb that had a vacuum. He later replaced the globe with a glass tube of about 2.5 feet (0.76m) emptied of air.[1] The glass tube was a less effective static generator than the globe, but it became more popular because it was easier to use.[2]
question: When was the electrostatic machine invented?
answers: 1663