Arago published, in the "Annuaire" of the Bureau des Longitudes, popular papers on natural phenomena and on the applications of science to industry. One of these dissertations was on thunder and thunderbolts. Another, which appeared in 1829, was on the history of the steam-engine; others were on rain, the cold of night, the ruddy moon, and the influence of the moon on terrestrial phenomena. He also published a paper on eclipses of the sun; and a total eclipse occuring in July, 1842, which could be favorably seen at Perpignan, he went there to observe it. Notice had already been taken of the aureole which appears around the moon during an eclipse, and to what are now known as the protuberances, and he gave his special attention to them.
Having been made perpetual secretary of the Academy of Sciences in 1830, he was accustomed to come early to the meeting every Monday, where he received foreign savants read the correspondence, and, if it was his day, began the sitting with an analysis of the papers offered; and so clear and so much sought for were his analyses, that the memoirs sent up were frequently indorsed "For M. Arago's day." He also accompanied his analyses with a history of the questions discussed and a criticism of the proposed solution, the authority of which was never contested. In a short time this audience, though evidently illustrious, seemed to him too restricted. He desired to extend it. He had found a close Academy, working without witnesses, with doors closed or only half opened to a few privileged persons. He had them opened wide to all the world; and, in order that science might be spread more rapidly and further, he invited journalists to attend the meetings, and provided a place for them where they could take notes. He further, in 1835, induced the Academy itself to publish its proceedings under the supervision of the perpetual secretaries; and this was the origin of the famous "Comptes Rendus."
As a deputy and member of the political body, Arago proposed a scheme for damming one of the arms of the Seine and establishing a system of turbine pumps by which Paris should be fully supplied with water, which was defeated by a ridiculous jest. He induced the municipal council to bore the Artesian well of Grenelle, which was a great wonder in its day. He secured a public recompense for Vicat, who had invented an economical hydraulic cement. And when Daguerre came forward with his wonderful invention, which made it possible to take an exact portrait, by the aid of the sun, in fifteen minutes, Arago explained the method before the Academy and expounded its capabilities.
While a member of the Legislative Assembly, Arago was attacked with a malady which resulted in a gradual loss of sight, that became total in 1852. Being unable to make further researches, he endeavored to gather up and reduce to form the unfinished work of his past career. The visible results of this effort were seven conferences which