If Galileo's experiment did not measure the speed of light, what did it measure?

Galileo's experiment measured mans reaction time.

Galileo's most famous experiment was the one took place in the Leaning Tower of Pisa, where he dropped two spheres of different masses and demonstrated that their time of descent was independent of their weight.

He, though, once tried to measure the speed of light by using distant lanterns with shutters and recording how long it took light to get to him from across the field. His only conclusion was that light-speed was too fast to be measured by that experiment.