When he had recovered and returned to his work, the Royal Institution provided him with a voltaic battery of six hundred double plates of four inches square, four times as powerful as any that had been constructed, and not long after, one of two thousand plates. Scientific papers were constantly coming from his pen. He soon decomposed boracic acid with the battery. By heating boron in oxygen, it burnt, and was reconverted into boracic acid. In his experiments with muriatic acid gas he found chlorine to be a simple substance, and discovered euchlorine, a compound of chlorine and oxygen. He had already been made a fellow of the Royal Society at twenty-five, and at twenty-nine one of the secretaries. His lectures were crowded, as ever, by a thousand people. The Dublin Society now invited him to give courses of lectures in 1810 and 1811, which he did, ticket-holders each paying ten dollars for a course. So difficult was it to gain admission to the lectures that many offered from fifty to a hundred dollars for a course ticket! He writes these facts to his mother, and adds, "This is merely for your eye: it may please you to know that your son is not unpopular or useless. Every person here, from the highest to the lowest, shows me every attention and kindness. "I shall come to see you as soon as I can. I hear with infinite delight of your health, and I hope Heaven will continue to preserve and bless a mother who deserves so well of her children." Trinity College, Dublin, conferred upon him the degree of Doctor of Civil Law. Cuvier said of him: "Davy, not yet thirty-two, in the opinion of all who could judge of such labors, held the first rank among the chemists of this or of any other age." The National Institute of France had awarded him the prize given by Napoleon to the greatest discovery by the means of galvanism. And yet all this fame and honor had been won by incessant labor. He writes to his mother: "At present, except when I resolve to be idle for health's sake, I devote every moment to labors which I hope will not be wholly ineffectual in benefiting society, and which will not be wholly inglorious for my country hereafter; and the feeling of this is the _reward_ which will continue to keep me employed." His brother John, who had been for three years at the Royal Institution, now went to Edinburgh to study medicine. Davy writes him: "Let no difficulties alarm you, you may be what you please. Trust me, I know what your powers are. Preserve the dignity of your mind, and the purity of your moral conduct. You set sail with a fair wind on the ocean of life. You have great talents, good feelings, and an unbroken and an uncorrupted spirit. Move straight forward on to moral and intellectual excellence. Let no example induce you to violate decorum,--no ridicule prevent you from guarding against sensuality or vice. Live in such a way that you can always say, the whole world may know what I am doing."