70 THE POPULAR SCIENCE MONTHLY. 



disinclined to talk about them, recollecting how they were laughed at 

 on the few occasions when they did so. The fact of their being com- 

 mon to scattered members of the same family has often been dis- 

 covered for the first time through my inquiries. I should say that I 

 have found no general accordance between particular letters and colors. 

 The relationship between them appears to be in each case a haphazard 

 one ; but having been once formed it is durable. 



Another and much more common oddity is the tendency to visualize 

 numerals in a peculiar manner, which characterizes, as I have roughly 

 reckoned, about one woman in every fifteen, and one man in every 

 thirty. Those who do so are never able to dissociate any single num- 

 ber from its own particular place in the field of their mental view, so 

 that when they think of a series of numbers they always visualize them 

 in a certain form. Either the numbers are all visible at once, as if they 

 were printed on cards and hung in space, according to some grotesque 

 pattern, or the mind travels along a blank but familiar path to the 

 place where the number that is thought of is known to reside, and 

 then it starts into view. There are many weird varieties of this singu- 

 lar tendency to visualize numbers in forms, which I have lately de- 

 scribed,* and will not here repeat. Suffice it to say, that they date 

 from an earlier period than that to which recollection extends. They 

 manifest themselves quite independently of the will ; they are inva- 

 riably the same in the same person, but are never the same in two 

 different persons, and the tendency to see them is strongly hereditary. 

 I have now a collection of hundreds of them, not only from English 

 men and women, boys and girls, but from American, French, German, 

 Italian, Austrian, and Russian correspondents. They are found useful 

 in the simpler kinds of mental arithmetic. 



Those who see number-forms have usually some equally persistent 

 scheme for dates, based more or less upon the diagrams of the school- 

 room. I am well acquainted with an accomplished student of history 

 whose mnemonic form for all historical events is a simple nursery dia- 

 gram, which has blossomed, as it were, into large excrescences whereon 

 the subsequently acquired facts are able to find standing-room. These 

 diagrams are really helpful, because their shape is correlated with the 

 subject they portray. They are not like the jingling nonsense verses 

 and bad puns upon which many persons base their memory of facts. 



The persistency of the forms under which numerals and dates are 

 visualized testifies to a want of flexibility in mental imagery which is 

 characteristic of many persons. They find that the first image they 

 have acquired of any scene is apt to hold its place tenaciously in spite 

 of subsequent need of correction. They find a difficulty in shifting 

 their mental view of an object, and examining it at pleasure in differ- 



* "Visualized Numerals," a Memoir read before the Anthropological Institute, March 

 9, 1880, about to be published in the forthcoming part of their journal of this year. See 

 also a previous Memoir in "Nature," February 15, 1880. 



