218 Life ami Letters of Francis Galton 



magnitude. The grade, beyond which the order was not correctly given, 

 measured the muscular sensitivity of the individual. Galton emplia-siswl the 

 fact that beyond true appreciation, the correct order might l>e given by 

 chance in, perhaps, one or another case. 



The important points here are: (1) How far the sense measured is touch 

 and how far muscular appreciation. In Galton's method of handling even 

 inertia might be a factor of the appreciation' (pp. 473-4). (11) Galton 

 assumes the geometrical law, and this plays a large part in his later work, 

 (ill) He does not suppose with Weber tliat IT and li vary from individual to 

 individual. He assumes a sort of population average value for IT and li. 

 I am by no means sure that his purjx)se could not have been accomplished 

 with equal eflectiveness by taking the first weight the same in each triplet 

 (or (luartet) and making the others proceed, not by ecjual ratios, but by 

 equal differences; in fact his geometrical series, except in the lowest grades 

 01 sensitivity , are very approximately arithmetic series. 



Galton remarks: 



" Blind persons are reputed to have acquired, in compensation for the loss of their eyesight, 

 an increased acuteness of their other senses. I was therefore curious to nmkc some trials with 

 my test apparatus, and I was permitted to do so on a nuinlx-r of boys at a large educational 

 blind asylum, but found that although tliey were anxious to do their Ix'st, their performances 

 were by no means superior to those of other boys. It so happeneil that the blind latis who 

 showed the most delicacy of touch, and won the little prizes I offered to excite emulation, 

 barely reached the mediocrity of the sighted lads of the same ages, whom I had previously 

 tested. I have made not a few oliservations and inquiries, and find that the guidance of the 

 blind depends mainly on the multitude of collateral indications, to which they give much heed, 

 and not in their superior sensitivity to any one of them. Those who sec do not care for so many 

 of these collateral indications, and habitually overlook and neglect several of them. I am 

 convinced also, that not a little of the popular Ijelief concerning tlie sensitivity of the blind is 

 due to occasional exaggerated statements that have not been experimentally veritied." (p. 475.) 



So Galton destroyed another of the beliefs, which are only held because 

 men in general have been too sluggish to test their truth experimentally. 



In a footnote added in March of the following year, 1883', Galton 

 endeavoured to distinguish l)etween the sense of touch and the sense of 

 muscular effort. He supposes the test object held in the palm of the hand, 

 palm uppermost, while the back of the extended hand rests on a broad and 

 padded stirrup, connected by a string with fixed pulleys and a counter- 

 balance weight. There is then no muscular effort to 8uj)port the weight, and 

 the hand can distinguish easily between the localised prtissure of the weight 

 on the palm and the "soft and broad pressure" of the stirrup on the back 

 of the hand. The counterbalance is then removed and the "operator" ex- 

 periences at once the muscular efforts necessary to supi)ort the weight and 

 distinguishes it from the mere pressure of the weight on the palm. 1 believe 

 Galton was the first investigator anywhere to measure mu.scular sensitivity 

 by the discrimination of weight Ixjxes. 



As Galton's anthropometric measurements of sensitivity and of physique 



' In the Anthropometric Room of the Galton Ivilwratory four not three weights are used 

 for each test. Each weight consists of a circular tin Ikjx loaded with shot, and is lifted by the 

 thumb ami two fingers without rocking. ' The pajier was read Nov. 14, 1882. 



