276 Life and Letters of Fraiwh Gaftoii 



mental images of the figures. Galton had tested Inaudi, in whom he found 

 the visual form of the imagination practicjvlly absent. Binet considere that 

 mental 'calculating Ikivs' did not i\.s a rule inlierit their gifts, the Bidder 

 fumily being a conspicuous instance of exception. CJalton was not pri-pared 

 to accept this view; he l)elieved that two mental j)eculiaritie8 must concur 

 to make a calculating lx)y, namely (i) .special capacity for mental calcula- 

 tion, and (ii) a jwussion for exercising it. Both are rare and are not neces- 

 sarily coordinated, so that the chance of their concurrence may be very 

 small indeed. He thought that (i) without (ii) might be commoner than is 

 usually believed, and he cited the case of a lady of remarkable ability, whom 

 he had known, and who did not discover that she possessed (i) until on a 

 long and dull railway journey in middle life. He then gives some account of 

 his own experience in performing arithmetic by imaginary smells and tastes. 

 In 1888 Galton published a paper on "Mental Fatigue'." This was a 

 subject in which fi-om personal experience he felt great interest. Over- 

 fatigue of the brain in schools had Ijeen recently discussed and illustrated 

 by experiences which flatly contradicted one another. After the heat of con- 

 troversy had somewhat cooled Galton was asked to occupy the chair at a 

 meeting of the educational Section of the Teachers' Guild, and he wjis so 

 struck by the audience on that occasion that he considered that the Guild 

 might be a powerful instrument for the solution of statistical problems, if 

 its intelligent members could l)e intere.sted in educational inquiries. Galton 

 accordingly issued a .schedule of .selected tjuestions bearing on mental fatigue. 

 He met with an experience, often repeated in the case of the present writer, 

 namely that circularising societies constituted for definite educational or 

 social work, even on points directly connected with their aims, produces 

 very little by way of useful statistical returns. Galton, although his schedule 

 was accompaniefl by a covering letter from the Vice-Chairman of the Guild, 

 received only 1 16 replies to his questionnaire, and all Galton was able to do 

 was to set down in an orderly way the replies received. The questions 

 asked applied not only to the taught, but to the teachers themselves. Of 

 the teachers themselves one-fifth, 23, had at some period in their lives broken 

 down, and no less than 21 of these had never wholly recovered from the 

 effects. The teachers also reported with detail 59 cases known to them of 

 more or less serious prostration from mental overwork. At the same time 

 it is jK).ssible that those teachers, who had themselves suffered from or 

 closely observed others suffering from overwork, would be most likely to 

 be interested in Galton's questionnaire, and thus the IIG replies be not a 

 random sample of all teachers. While the answers showeil many views on 

 the signs of mental fatigue, and on the studies which could or could not be 

 undertaken when the mind was fatigued, there was little light thrown on 

 the best means of testing mental fatigue, or of measuriruj it in a school-class 

 at large. In fact the only real light on this matter came from Galton himself 



' "Kcmarkg on llnplies by Ti'Achers to Questions msiKfting Mental Fiitigue," ./ournn/ <//' 

 th» AntJirojto/oyieal In»l\luU, Vol. xvni, pp l.'iT-Gft. 



