Psi/c/io/of/icdl hirentif/atiouji 



221 



horizontal portion a Hniall in(lia-rubl)er bull / is firmly attached, which rests 

 against tlio fixed Imrt'er //, when the top of the cvlimler E is at the zero of 

 the scale. The hall / nmst Ixt against // when the limb is fully extended. 

 T represents the direction of the string carried to the moving limb. The 

 (litltTential nnlley reduces the motion to ^ that of the moving limb. The 

 height h in niches reached l)y E for a given velocity w of / on impact is 

 00207 xur', which allows of an easy gramiation of the scale. 



To me;isure the velocity of a blow Galton pliujes the examinee with his 

 back to a wall, and he strikes at a long feather, so adjusted that (i) when 

 the Hst reaches the feather the india-rubber ball .strikes the butter. Care 

 must bo taken (ii) that the wrist is rtot bent, and (iii) that the extended 

 horizontjd limb is in the horizontal line of the string : the free end of the 

 string is attaclied to the fist. The machine retiuires vertical and horizontal 

 adjustments to allow of the fidfilment of (i) and (iii). Galton states that the 

 instrument liad worked s<iccessfully in his lalHiratory. It neglects the resist- 

 ance of the air on the small l)ead or cylinder E, together with the possible 

 friction of the steel wire, and the additional acceleration due to the pull of 

 the string on the limb ; all these are however very .secondary factors, and 

 might, were it necessary, be allowed for. As usual with (ialton's apparatus, 

 the constituents are of the simplest character, and any man with a mode.st 

 mechanical knowledge could rig up such an instrument. 



A dirterent anangenieiit for measuring the velocity of a blow was used 

 by Galton in 1882. It is figured by Galton in his account of his first 

 Anthropometric Lalioratory', to which we shall refer later, but the instru- 

 ment was discarded as it was liable to be injured if the blow was not a 

 straight one, and occasionally in that case the experimentee injured himsell"! 

 The instruments were chiefly devised by Galton himself, and included : 



(«) For Hearing : both Acutencss and the Jliyhest audible Xote. 



Under sound we first reach a point on which Galton was rather insistent, 

 namely that the sensitivity of women, the fineness of touch, of hearing, of 

 taste, etc., was not greater than that of men, although the contrary had l^een 

 often asserted. Galton tested with four of his whistles, giving 20,000, 30,000, 

 40,000 and 50,000 vibrations a second", with the following results : 



' "On the Anthropometric Liiboratory at the lat« International Health Exhibition." 

 Journal of (he Anthropological Institute, Vol. xiv, pp. 205-212, 1885. 



' I feel some doubt as to the accurate standardisation of these whistles. 



