The New York herald., 1921-01-09
A Blind Prodigy.
A Natural Mathematician Who Has
Cultivated His Gifts.
From the Literaru Dioest.

From the Literary Digest.
A remarkable case. in which extraor-
dinary ability in arithmetical calculation
is associated with general mental infe-
riority. II not actual insanity. is quoted
by the Lancet from L'EncephoIe, q
French paper. The patient is a young
man of 26. named Fleury. who is COM
plete1y blind. It seems that Fleury has
consciously developed his ability. in
which he differs from the usual calcu-
lating phenomenon. who often performs
his feats without having trained for it.
Partly by perseverance with the Braille
method. partly by devising certain mem
tai tips of his own. he has reached a
stage Of extraordinary facility In per-
forming elaborate calculations. F1eury.
for example. can give the square root
Of any number running into four figures
in an average Of four seconds, and the
cube root Of any number running into
six figures in six seconds; he gave the
cube root Of 84.012.224-324-in eleven
seconds and the cube root of 465 5,484.375
-775-in thirteen seconds.
These seem mere trifles, however.
compared with the following examples:
He was asked how many grains Of corn
there would be in any one of sixty-four
boxes, with one in the first, two in the
second. four in the third. eight in the
fourth and so on in succession. He
gave the answers for the fourteenth
(S.192). for the eighteenth (131,072)
and the twenty-fourth (S,3SS,60S) in
simultaneously, and he gave the figures
for the forty-eighth box (140,737,4SS,-
355.32S) in six seconds.
Further, on the request to give the
total in all the boxes UP to and includ-
ing the sixty-fourth. he furnished tho
correct answer (1s.446.734.073 .7o9.551.-
615) in forty-five seconds. When it rs
from birth and can have no visual men,
ories the feat becomes really impressive,
In an average OF twelve seconds he can
divide any number, say Of four
figures. into its prime factors. thuse
1924 -2a XII < 43; 5564 -2sx 13
x107r; and SO on.
According to DR.. Lotte. Fleury can
give the day for Easter In any year, in
the Gregorian and Julian calendars re-
SPSeSHCiJ, hhu sAihhAtdhCOu5iyp Oy oohtS
scheme equally original, of which the des
tails are not, however. supplied. Thus
in 1862 Easter fell on April 81 and
March 81 respectively e. minutes 10
seconds) In 1746, March 80 and April
10 e. minutes 20 seconds). and for 1946
the dates are April IL and April II GO
seconds).
Numerous other illustrations are fur
nished OF this altogether remarkable
case, which certainly equals, II It does
not surpass, others that have becoms
classical.
It Is interesting to learn, on tho au-
thority OF DIR. Lotto. that, thanks to
more general recognition OF F1eury's
exceptional gifts. the opportunity is to
be afforded him OF further education and
instruction. and It Is quite possible he
win rise to still greater heights OF arith--
metical attainment and Of mathematical
attainment in a wider sense, IL he Is
handled by some professional exponena
Of these subjects. In any case the psy-
Geological interest and importance Of
such a wonderful example OF develop-
ment OF a practically isolated mental
faculty warrant our giving the cass
greater publicity.