Ampère learned to read when but very young, and then began to devour all the books which came to hand. Usually, the precocious taste for reading specializes on some particular subject; but everything was grist that came to the child Ampère's mental mill, and it was all ground up; and, strangest of all, much of it was assimilated. Travel, history, poetry, occupied him quite as much as romance; and, amazing as it may appear, even philosophy was not disdained while he was still under ten years of age. It seems amusing to read the declaration of the French biographer, that if this boy of ten had any special predilection in literature, it was for Homer, Lucan, Tasso, Fénelon, Corneille and Voltaire, yet it must be taken seriously. When he was about fifteen, this omnivorous intellectual genius came across a French encyclopedia in twenty folio volumes. This seemed to him a veritable Golconda of endless riches of information. Each of the volumes had its turn. The second was begun as soon as the first was finished, and the reading of the third followed, and so on, until every one of the volumes had been completely read. References to other volumes might be looked up occasionally, but this did not distract him into taking other portions of the works out of alphabetical order. Surprising as it must seem, most of this heterogeneous mass of information, far from being forgotten at once, was deeply engraved on his wonderful memory. More than once in after-life, when many years had passed, it was a surprise to his friends to find how much information Ampère had amassed on some abstruse and unfamiliar subject, and how readily he was able to pour forth details of information that seemed quite out of his line. He would then confess that the encyclopedia article on the subject, read so many years before, was still fresh in his mind, or at least that its information was so stored away as to be readily available. We have heard much of Gladstone's memory in more recent years; but that seems to have been nothing compared to this wonderful faculty which recalled for Ampère, even as an old man, the unrelated details of every encyclopedia article that had passed under his eyes half a century before, when he was a boy of ten to fourteen.