60 THE POPULAR SCIENCE MONTHLY. 



the earth. Besides saving from waste the products of decay, 

 these roots must add considerable strength to the weakened 

 trunk. This feature is perhaps all the more significant in view of 

 the mulberry's near kinship with the banyan tree, which makes 

 such wonderful mechanical use of aerial roots. 



With regard to the way in which such economizing roots 

 originate, and their physiological significance, it seems clear, as 

 Mr. Sudworth has suggested, that the conditions necessary for 

 their production are essentially the same as those favoring root- 

 production in cuttings and layered branches. That is to say, 

 given a vigorous cambium or similar formative tissue, near a 

 more or less injured region, the presence of moisture for a certain 

 period, and a congenial soil, then adventitious roots may be ex- 

 pected to appear. That in all the cases above cited these condi- 

 tions were most probably present antecedent to the appearance of 

 the roots seems surely to be a fair inference from all we know 

 regarding them. 



When, as in Mr. Buckhout's maple, there is opportunity for 

 dust, etc., to accumulate in a small cleft near the callus, before 

 total separation of the limb, the conditions are practically the 

 same as in those not uncommon cases where seeds are found to 

 sprout in the fork of a tree and grow for a number of years. 



Now that the attention of observers has been called to this 

 curious power which trees have of making the best of a bad mat- 

 ter, it will doubtless be found that the phenomenon is of more 

 common occurrence than was at first suspected. 



THE LATEST ARITHMETICAL PRODIGY. 



By M. ALFKED BINET. 



MATHEMATICIANS, doctors, and philosophers have lately 

 enjoyed a rare opportunity to study a new calculating 

 prodigy, a young man twenty-four years old, who performs men- 

 tally, with surprising rapidity, operations in arithmetic involving 

 a large number of figures. We purpose, pertinently to his case, 

 to consider the psychological aptitudes which serve as the basis 

 of mental calculation. We shall use in our study the report of 

 the committee of the Academy of Sciences which examined M. 

 Inaudi, and the results of our own personal observations of his 

 powers, by which we are convinced that he can bear comparison, 

 for the extraordinary development of his memory, with all other 

 known calculators. Jacques Inaudi was born at Onorato, in 

 Piedmont, on October 13, 1867, of a family in modest circum- 

 stances. He passed his earlier years in tending sheep. At the 



