THE POWER OF MEMORY. – Seneca could repeat two thousand verses at once, in order, then begin at the end and repeat them backwards, without missing a single syllable. Cyrus is said to have been able to call every individual of his numerous army by his proper name. Mithridates, who governed twenty three nations, all of different languages, could converse with every one of them in their own language. In modern times there have been many instances of extraordinary powers of retention. Dr. Wallis, in a paper in the “Philosophical Transactions,” informs us that he extracted the cube root of the number three even to thirty places of decimals by the aid of memory alone. M. Euler, the celebrated mathematician, who died 1783, lost his sight by too intense application to study, but he afterwards composed his “Elements of Algebra,” and the work “On the inequalities of the Planetary Motions,” that required immense and complicated calculations, which he made by memory alone. His memory seemed to retain every idea that was conveyed to it either from reading or from mediation, and his powers of reasoning and discrimination were equally acute and capacious. He was also an excellent classical scholar, and could repeat the “AEneid” of Virgil from the beginning to the end, and indicate the first and last line of every page of the edition used. I have conversed with an individual, who was born blind, and who could repeat the whole of the Old and New Testament from beginning to end; and not only so, but could repeat any particular chapter or verse that might be proposed to him the moment after it was specified. -