Electricity is a fundamental feature of all matter. Great advances in the study of electricity were made in the 17th and 18th centuries, however, during the late 19th century engineers were able to put it to industrial and residential use. William Gilbert first introduced the study of electricity and magnetism in 1600 and published a book regarding his findings. Benjamin Franklin discovered electricity and lightning were one and the same and his lightning rod was the first practical application of electricity. In 1747, Henry Cavendish started measuring conductivity, the ability to carry an electrical current, of different materials. The explosion of study and experimentation in electric currents, magnetic fields, electro-chemistry and voltage have had far-reaching affects throughout all areas of science.