On the last day of 1879, Edison invited a select audience to come and witness a demonstration of his new incandescent lights. As they arrived at his estate at Menlo Park, New Jersey, they were wowed by the sight of two buildings warmly aglow. What they didn’t realize was that the light was mostly non-electrical. Edison’s overworked glass blowers had been able to prepare only thirty-four bulbs, so the bulk of the illumination actually came from carefully positioned oil lamps.
