In our chapter on the accumulator or storage cell we saw that a current of electricity has the power of decomposing certain liquids; that is to say, it is able to split them up into their component parts. This power has given rise to the important art of electroplating and electrotyping. Electroplating is the process of depositing a coating of a rarer metal, such as gold, silver, or nickel, upon the surface of baser or commoner metals; and electrotyping is the copying of casts, medals, types, and other similar objects. The fact that metals could be deposited by the decomposition of a solution by a current was known in the early days of the voltaic cell, but no one seems to have paid much attention to it. An Italian chemist published in 1805 an account of his success in coating two silver medals with gold, and some thirty years later Bessemer transformed lead castings into fairly presentable ornaments by coating them with copper, but commercial electroplating may be said to have begun about 1840, when an Englishman named Elkington took out a patent for the process. Since then the processes of electroplating and electrotyping have rapidly come more and more into use, until to-day they are practised on a vast scale, giving employment to thousands. Electroplating on a small scale is a very simple affair. A solution of the metal which it is desired to deposit is placed in a suitable vessel. Two metal rods are placed across the top of this vessel, and from one of these is suspended a plate of the same metal as that in the solution, and from the other is hung the article to receive the coating. The positive terminal of a voltaic battery is connected to the rod supporting the plate, and the negative terminal to the rod carrying the article to be plated. As the current passes through the solution from the plate to the article the solution is decomposed, and the article receives a coating of metal. The solution through which the current passes, and which is decomposed, is called the _electrolyte_, and the terminal points at which the current enters and leaves the solution are called _electrodes_. The electrode by which the current enters the electrolyte is called the _anode_, and the one by which it leaves is called the _cathode_.