642 The American Naturalist. [July, 
PSYCHOLOGY.’ 
Rapid Calculators.—In 1894 Prof. Binet published an elaborate 
series of tests made on two well-known “lightning calculators,” Diam- 
andi, a Greek, and Inaudi, an Italian. A notable result of these tests 
was to show that while one of the pair, Diamandi, was of a visual type, 
like most professional calculators, the other, Inaudi, was exceptional 
in being auditory. Thus while the former committed numbers to 
memory more readily when they were written out, and was able to 
repeat a square of figures, once memorized, by rows or columns with 
equal facility, the latter learned numbers more rapidly when they were 
given orally, or by speaking them himself, and found it difficult to 
repeat them afterwards in any other order than that in which he had 
committed them. Inaudi always accompanied his calculations by 
slight lip and throat movements, and when asked to make a constant 
and uniform sound during his work, declared himself wholly unable to 
perform the required operations. i 
These observations have recently been supplemented by a monograph 
study by Sign. Guicciardi and Ferrari? of an Italian, Ugo Zaneboni, 
who has lately been giving exhibitions of his skill as a calculator. 
They found him to be visual in type, like Diamandi, with whom, how- 
ever, he could not compare for speed and versatility. 
The most noticeable point about Zaneboni is the wide difference be- 
tween his power of acquisition and his power of retention. In the former 
respect he is decidedly mediocre. Thus he required nearly seven min- 
utes to memorize a series of 25 numbers, which he was told were to be 
repeated by him the next day; the next day he was unable to give 
more than the first four correctly. On the other hand, his power of 
retention was extraordinary. Its material appeared to be supplied by 
an automatic process of acquisition, since voluntary memorizing on his 
part was possible only by a distinct effort of the attention. During his 
years of military service, Zaneboni was frequently posted at a railroad 
station. He spent his spare time there in reading and re-reading the 
time-tables ; as a result he is now able to give correctly from memory 
the distances between any two places in Italy, with the fares for each 
class. At another period in his life he memorized a list of 227 cities, 
Italian and foreign, with their population, which he uses in his public 
1 Edited by Howard ©. Warren, Princeton University, Princeton, N. J. 
? Rivista Sperim, di Freniatria, 1897, XXIII, fasc. 1 and 2. 
