Having in 1820 a more powerful voltaic battery in operation than previously, he repeated[17] the operation of bringing near to the compass needle the copper wire that conveyed the current; and, laying it parallel to the needle’s direction, and over or under it, found that the needle tended to turn into a direction at right angles to the line of the current, the sense of the deviation depending upon the direction of flow of the current, and also on the position of the wire as to whether it were above or below the needle. A current flowing from south to north over the needle caused the north-pointing end of the needle to be deflected westwards. If the wire were vertical, so that the current flowed downwards, and a compass needle was brought near the wire on the south side, therefore tending under the earth’s directive influence to point northwards toward the wire, it was observed that the effect of the current flowing in the wire was to cause the north-pointing end of the needle to turn westwards. Or, reversing the flow of current, the effect on the needle was reversed; it now tended eastwards. All these things Oersted summed up in the phrase that “the electric conflict acts in a revolving manner” around the wire.[18] In modern phraseology the whole of the actions are explained if one can conceive that the effect of the electric flow in the wire is to tend to make the north pole of a magnet revolve in one sense around the wire, whilst it also tends to make the south pole of the magnet revolve around the wire in the other sense. The nett result in most cases is that the magnetic needle tends to set itself square across the line of the current. Oersted himself was not too clear in his explanations, and seems, in his later papers, to have lost sight of the circular motion amidst repulsions and attractions. This discovery, which showed what was the geometrical relation between the magnet and the current, also showed why the earlier attempts had failed. It was requisite that the electricity should be in a state of steady flow; neither at rest as in the experiments with electric charges, nor yet in capricious or oscillatory rush as in those with spark-discharges. Faraday, adverting a quarter of a century later to Oersted’s discovery, said: “It burst open the gates of a domain in science, dark till then, and filled it with a flood of light.” The very day that Oersted’s memoir was published in England, Davy brought a copy down into the laboratory of the Royal Institution, and he and Faraday at once set to work to repeat the experiments and verify the facts.