1888.] 



Co- relations and their Measurement. 



137 



prejudicial to the conclusions that will be reached. They were 

 measured in various ways, partly for the purpose of this inquiry. It 

 will be sufficient to give some of them as examples. The exact number 

 of 350 is not preserved throughout, as injury to some limb or other 

 reduced the available number by 1, 2, or 3 in different cases. After 

 marshalling the measures of each limb in the order of their magni- 

 tudes, I noted the measures in each series that occupied respectively 

 the positions of the first, second, and third quarterly divisions. Calling 

 these measures in any one series, Q lf M, and Q 3 , I take M, which is 

 the median or middlemost value, as that whence the deviations are 

 to be measured, and i{Qs Qi} = Q, as the probable error of any 

 single measure in the series. This is practically the same as saying 

 that one-half of the deviations fall within the distance of +Q 

 from the mean value, because the series run with fair symmetry. In 

 this way I obtained the following values of M and Q, in which the 

 second decimal must be taken as only roughly approximate. The 

 M and Q of any particular series may be identified by a suffix, thus 

 M c , Q c might stand for those of the cubit, and M 5 , Q, for those of the 

 stature. 



Table I. 



NOTE. The head length is its maximum length measured from the notch 

 between and just below the eyebrows. The cubit is measured with the hand prone 

 and without taking off the coat ; it is the distance between the elbow of the bent 

 left arm and the tip of the middle finger. The height of the knee is taken sitting 

 when the knee is bent at right angles, less the measured thickness of the heel of 

 the boot. 



Tables were then constructed, each referring to a different pair of 

 the above elements, like Tables II and III, which will suffice as 

 examples of the whole of them. It will be understood that the Q 

 value is a universal unit applicable to the most varied measurements, 

 such as breathing capacity, strength, memory, keenness of eyesight, and 

 enables them to be compared together on equal terms notwithstand- 

 ing their intrinsic diversity. It does not only refer to measures of 



