Joseph Priestley independently isolated oxygen in its gaseous state, calling it "dephlogisticated air", and published his work before Scheele. During his lifetime, Priestley's considerable scientific reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the most famous being what Priestley dubbed "dephlogisticated air" (oxygen). However, Priestley's determination to defend phlogiston theory and to reject what would become the chemical revolution eventually left him isolated within the scientific community. In 1781, Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from Cronstedt's scheelite (at the time named tungsten). Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid. In 1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, in Spain, the brothers succeeded in isolating the metal now known as tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element. Volta and the Voltaic pile Italian physicist Alessandro Volta constructed a device for accumulating a large charge by a series of inductions and groundings. He investigated the 1780s discovery "animal electricity" by Luigi Galvani, and found that the electric current was generated from the contact of dissimilar metals, and that the frog leg was only acting as a detector. Volta demonstrated in 1794 that when two metals and brine-soaked cloth or cardboard are arranged in a circuit they produce an electric current. In 1800, Volta stacked several pairs of alternating copper (or silver) and zinc discs (electrodes) separated by cloth or cardboard soaked in brine (electrolyte) to increase the electrolyte conductivity. When the top and bottom contacts were connected by a wire, an electric current flowed through this voltaic pile and the connecting wire. Thus, Volta is credited with constructing the first electrical battery to produce electricity. Thus, Volta is considered to be the founder of the discipline of electrochemistry. A Galvanic cell (or voltaic cell) is an electrochemical cell that derives electrical energy from a spontaneous redox reaction taking place within the cell. It generally consists of two different metals connected by a salt bridge, or individual half-cells separated by a porous membrane. Antoine-Laurent de Lavoisier Antoine-Laurent de Lavoisier demonstrated with careful measurements that transmutation of water to earth was not possible, but that the sediment observed from