Page:Popular Science Monthly Volume 46.djvu/751

Rh It is evident that Inaudi has a mind developed largely in one direction, but undeveloped in others.

Another instance of a lightning calculator may be mentioned, because he presents a wholly different method in his mental action. I refer to M. Diamandi, who has recently been examined carefully by Prof. Binet, of Paris. Diamandi is able to perform wonderful feats of mathematical calculation with great rapidity, but he can not make his calculations until the numbers given him are written down. In other words, he is a visualist; he calls to mind numbers as they appear when seen. He says the numbers appear as if written on a mental table, which he sees and reads when he is asked to repeat numbers from memory. If Diamandi receives a problem by ear, he hesitates, appears embarrassed, commits errors, and demands a repetition. It is necessary for him to call up the visual image of the numbers heard. But when a problem is given in writing, he glances at the paper, then closes his eyes, makes an effort to call these numbers to mind, quickly goes through the calculation, and reaches the result, which he seems to himself to read off from the mental tablet. According to his statement, the numbers appear to him as if written in his own handwriting. Thus, if the problem is written in ink on a white paper, the figures in his mind appear in the same black color on white; but if it is written with chalk on a blackboard, it is thus that the result comes to his mind. His time of calculation is slightly longer than that of Inaudi,

The more the processes of thought in such minds are analyzed and contrasted with those in normal minds, the more apparent it becomes that each individual has his preference m mental imagery, and that in each person the mind habitually works more actively through one sense than through the others. This distinction was most acutely drawn by Charcot, who classified people into "visualists"—those whose recollections were chiefly of things seen, who had to read a name in order to remember it;