Daily Arizona silver belt., 1907-01-31
WIZARDS OF MEMORY
{ AMOUS MEN WHO HAD WONDER
 FLU POWERS OF RETENTION.

The Remarkable and Authentic Case'
 of Leonard Euler, the MathemRi'
 elan, MagIiabechi, the Literars
 Prodigy, and Rev. Dr. John Wallis.
 Writers on psychology and phlloso
 rhy have cited many examples of pro
 gious memory. No doubt some oi lhese are congregations, others are fab
 ;.lous, and onS comparatively few
 admit of verificatiou, Recently l have
 found in my reading three cases SC
 well authenticated that they may be
 used to illustrate the wonderful power
 of we'll cultivated memory in mind
 of strong native endowment. In each
 instance, too, this remarkable reten'
 tiveness seems in no way to have re
 tarded the fullest development of other
 mental powers,
 Probably the most remarkable of the
 three was the memory of Leonard
 Euler. Euler was native Of Basel,
 but most of his life was spent in St,
 Petersburg He was born in HOT and
 died in 1TS3. He was a teacher of great power and a most prolific writer.
 More than half of the forty-siX quarto
 volumes of mathematics published by
 the St. Petersburg academy between 1727 and lIS3 were from his pen. At his death he left more than POO manu- script treatiseS.
 In the later years of his life he was totally blind Then, and probably ear. Her, too he carried in his memory a table of the first six powers of the ''serles of natural numbers up to a hundred" It is related that on one oc. casion two of his students attempted to calculate a conyerging series, AS they progressed they found disagreement in their results. These differed by a unit at the fiftieth figure The question was referred to Euler, who decided to make the calculation. IEe did this mentally, and his result was found to be cor rect
 It was not only in mathematics that Euler gave proof of a prodigious mem ory. He was well read in general liter ature and was an excellent classical scholar. Virgil was one of his fayorite writers It Is said that he knew this author so well that he could repeat the "Aeneid" from beginning to end with out hesitation and indicate the first and last line of every page of the edi- ton which he used"
 The seventeenth century furnishes the other two instances. to which l call especial attention. The first is that of the Italian scholar Antonio da Marco Magliabechi. Magliabechi was the llt- erary prodigy of his time. Royalty and other distinguished personages paid tribute to his wonderful learning. His contemporaries have said that his memory was SO pr0digious that he was able to retain verbatim most of the contents of his 'multltudinous books"
 A comparatively recent writer has declared that Magllahechi could name all the authors that had written upon any subject. giving the name of the book, the words and often page This Is doubtless congregation: but on the other hand 1t should be remembered that the number of books on any sub Ject were much fewer then than at the present day. Besides this. there are two stories that have come down from Magllabechl's time to ours that give color to its truth. On one occasion a gentleman of Florence desired to test Magllabechl's memory and ascertain for himself whether the wonderful stories told were truth or fiction. He gave him a manuscript 10 read; then. some days after its return. pretending to have lost il, he asked Magllabechl to recall it, which, 1t Is said. he did with remarkable eXactness. At another time the grand duke of Florence asked if he could procure a certain book for him. Immediately came the response: "No, sire; 1t is impossible There is but one In the world. That Is in the grand seignior's library at Constantlnople and Is the seventh book on the seventh shelf on the right hand as you go in"
 The other instance in the seventeenth centiry is that of the Rev. Dr. John Wallis. It Is not. however. as theo- logian that Wallis name Is enrolled in the temple of fame, but as mathema- ticlan. In mathematical history he ranks as the greatest of Newton's Eng llsh precursors. He was started on his career by reading Ough- tred's "Clavic Mathematics" but the ] special bent of hls genius came from Torricelli's writings on ''The Method of | lndivisibles." To this he applied the | Cartesian analysis and produced his | great work. the "Arithmetlca Infnitori- | most stimulating mathe- | nautical work so far published in Eng | land" Here he makes the successful | attempt to solve a number of the more simple problems of the calculus by the of series to lniinlty. The | work was one of great influence. New | ton read It while an undergraduate at the university and from 1t immediately derived his blnomial formula. The power of concentration and of memory were both very strong with Wallis-so strong. it Is said that on one occasion while In bed in the dark he extracted the square root of a number of fifty three places to twenty-seyen terms and the result twenty days after ward"
 These examples of retentlye memory Ire quite well authenticated and give to the possible truth of otn- ITS frequently cited. Pllny tells us hat Cyrus the Great knew the names