In an effort to showcase the dangers of alternating current (AC) and discredit Nicola Tesla, Thomas Edison held public demonstrations in which he electrocuted animals—dogs, cats, horses, and even an elephant—in front of an audience.
The bitter rivalry between Thomas Edison and Nicola Tesla is now the stuff of legend, and it all came to a head during the War of the Currents. On the one side, Edison felt that direct current (DC) was the wave of the future. On the other side, Tesla believed that alternating current (AC) was more efficient for transmitting power over longer distances. Edison launched a massive public campaign to discredit AC, while Tesla partnered with financial mogul George Westinghouse in an attempt to convince power companies to switch over to AC using Tesla’s patented AC induction motor.
By this point, the two inventors were old acquaintances, although there was nothing friendly about their relationship. When Tesla moved from France to New York in 1884, the penniless immigrant got a job at the Edison Machine Works as an engineer. Within a year, he was already solving technical problems for the company, and Edison approached him with the task of redesigning the DC generators for the entire company. He famously offered Tesla $50,000 if he could make the generators more efficient, and a few months later, Tesla came back with an improved design. But when he asked for his money, Edison laughed and said, “When you become a full-fledged American, you will appreciate an American joke.” Since Tesla had redesigned the generators while working for Edison, he had no claim to the patent, and essentially got nothing out of the agreement (although Edison offered him a raise of $10 per week. Tesla resigned on the spot).
A few years later, Tesla built his AC induction motor, and the War of the Currents began. Edison’s main campaign strategy was to prove that AC, which used much higher voltages than DC, was simply too dangerous to use in homes. And to prove that, he went to ruthless extremes. Most famously, he organized demonstrations executing stray dogs and cats, and later cows and horses. One of the first demonstrations took place in 1888, with the electrocution of a large dog named Dash. Edison first sent 1,000 volts of DC through the dog to prove that he would be—if not unharmed—still alive. Then, he hooked the dog up to 300 volts of AC and smoked the pup into oblivion.
And he was just getting warmed up. In 1903, Edison created his largest demonstration yet: He sent 6,600 volts of AC through a circus elephant named Topsy while 1,500 people stood by and watched. The execution was filmed and later released under the name Electrocuting an Elephant.
The real test came in 1890 though, and it was no ordinary animal: The victim was a convicted murderer named William Kemmler. Edison campaigned for the opportunity to create a “more humane” method of capital punishment and, still in the midst of the War of the Currents, he opted to create the electric chair with AC. After all, what better way to prove the dangers of AC than by killing a man with it? And he couldn’t have asked for a more visceral demonstration: The first charge burned through Kemmler’s insides for a whole 17 seconds, after which he was still gasping for breath. The second charge lasted four minutes, and Kemmler burst into flame before finally dying.