The Lomonosov Helicopter From 1754
It was an unimpressive demonstration. It was a box, and above the box, protruding out of the center of the top, a long transmission shaft. The inventor is Russian scientist Mikhail Vasil’evich Lomonosov, and the year is 1754. Lomonosov had the idea to attach counter rotating rotors over a small barometer would allow us to measure the pressure higher up in the atmosphere.
During the demonstration, the box never actually lifted off of a surface. Instead, it was suspended by a string attached to a counter weight. When turned on, it lifted further up in the air, giving the distinct impression that it was providing lift.
The interesting solution that came so earlier was the realization that a single rotor would cause the box to rotate in the opposite direction. The first vertical lift aircraft solved that problem with counter rotating twin rotors.
Source: Wikipedia, http://ram-home.com/ram-old/lomonosov-h1.html, Wired