A significant breakthrough occurred when Alessandro Volta (1745-1827) in Italy constructed a simple electric cell (in 1799) which produced a flow of electrons by chemical means. Two plates, one of copper and the other of zinc, were placed in an acid solution and a current flowed through an external wire connecting the two plates. Later he connected cells in series (voltaic pile) which consisted of alternate layers of zinc and copper discs separated by flannel discs soaked in brine or acid which produced a higher electric pressure (voltage). But Volta never found the right explanation of why his cell was working. He thought the flow of electric current was due to the contact between the two metals, whereas in fact it results from the chemical action of the electrolyte on the zinc plate. However, his discovery proved to be of incalculable value in research, as it enabled scientists to carry out experiments which led to the discoveries of the heating, lighting, chemical and magnetic effects of electricity. One of the many scientists and physicists who took advantage of the 'current electricity' made possible by Volta's cells was Hans Christian Oersted (1777-1851) of Denmark. Like many others he was looking for a connection between the age-old study of magnetism and electricity, but now he was able to pass electric currents through wires and place magnets in various positions near the wires. His epoch-making discovery which established for the first time the relationship between magnetism and electricity was in fact an accident. While lecturing to students he showed them that the current flowing in a wire held over a magnetic compass needle and at right angles to it (that is east-west) had no effect on the needle. Oersted suggested to his assistant that he might try holding the wire parallel to the length of the needle (north-south) and hey presto, the needle was deflected! He had stumbled upon the electromagnetic effect in the first recorded instance of a wire behaving like a magnet when a current is passed through it. A development of Oersted's demonstration with the compass needle was used to construct the world's first system of signaling by the use of electricity. In 1837 Charles Wheatstone and William Cooke took out a patent for the world's first Five-needle Telegraph, which was installed between Paddington railway station in west London and West Drayton station a few miles away. The five copper wires required for this system were embedded in blocks of wood.