Page:Popular Science Monthly Volume 4.djvu/349

 least what is commonly understood by the term—plays a very unimportant part. Of course a weak memory is an almost fatal obstacle to effective thought; but I am not comparing the worth of a good memory and a bad one, but of an average memory and one exceptionally powerful. I conceive that quite a large proportion of the most profound thinkers are satisfied to exert their memory very moderately. It is, in fact, a distraction from close thought to exert the memory overmuch; and a man engaged in the study of an abstruse subject will commonly rather turn to his book-shelves for the information he requires than tax his memory to supply it. The case resembles somewhat that of the mathematician who from time to time, as his work proceeds, requires this or that calculation to be effected. He will not leave the more engrossing questions that he has in his thoughts, to go through processes of arithmetic, but will adopt any ready resource which leaves him free to follow without check the train of his reasoning.

It would be perhaps difficult to devise any means of readily measuring mental power in examination or otherwise. The memory test is assuredly unsafe; but it would not be easy to suggest a really reliable one. I may remark that only those experienced in the matter understand how much depends on memory in our competitive examinations. Many questions in the examination-papers apparently require the exercise of judgment rather than memory; but those who know the text-books on which the questions are based are aware that the judgment to be written down in answer is not to be formed but to be quoted. So with mathematical problems which appear to require original conceptions for their solution: in nine cases out of ten such problems are either to be found fully solved in mathematical works, or others so nearly resembling them are dealt with that no skill is required for their solution.

I must confess that I am somewhat surprised to find Wendell Holmes, whose opinions on such matters are usually altogether reliable, recommending a test of mental power depending on a quality of memory even inferior to that usually in question in competitive examinations. "The duration of associated impressions on the memory differs vastly," he says, "as we all know, in different individuals. But in uttering distinctly a series of unconnected numbers or letters before a succession of careful listeners, I have been surprised to find how generally they break down, in trying to repeat them, between seven and ten figures or letters; though here and there an individual may be depended on for a larger number. Pepys mentions a person who could repeat sixty unconnected words, forward or backward, and perform other wonderful feats of memory; but this was a prodigy.