Really, you were asked to name the earliest! Who knew that you should look so deep into the ancient times (but some of you really did!). Thales of Miletus was the first to be interested in the nature of electricity. He noticed that amber if rubbed together with wool produces an effect of drawing smaller elements to it. His only mistake was to suppose that only amber possesses such a quality of drawing. Nevertheless, his input into the science of Physics was priceless. If not for his experiment, William Gilbert might not have had an opportunity to prove that not only amber has such a curious peculiarity, but also diamond, sapphire, glass and many others.