130 
ME. G. UDXY YULE ON THE THEOEY OF CONSISTENCE 
jiositively associated,” would be inferring almost the direct contrary of the truth. 
The real inference is “some A’s are not B,” or “A and B are not completely asso¬ 
ciated.” Similarly from the given values of (AB) and (BD), or of (AC) and (CD) in 
the case of the girls, he could only infer “some D’s are not A” ; and from (AB) and 
(BD) in the case of the girls again, “ some D’s are not B.” 
§ 36. In order to illustrate the case completely I give sketches of the congruence- 
surfaces in figures 16—19 for the hoys and 20—-23 for the girls,^ and have marked in 
each figure the co-ordinates corresponding to the actual values of (AB)/(w), &;c. 
Note that the figures are ou a much larger scale than those previously given. In fisjs. 21 and 22 the 
width of the narrow strip cut off on the plane (AD);(m) = -0682 has been'somewhat exaggerated. 
