Pliot<)<ir(ti>liic ReHearrhen and Port mil nre 



315 



ami negative a have the same tone, so that if 6 were «, the composite would 

 give merely medium grey. It is nee<lful also that /x>». n and neg. a should 

 accunitely antagonise one another. Our figure shows one of the illu.strations 

 (talton gave at the lecture, namely the "transformer" whioh will change an 

 T into a G. 



F + 



F- 



a + 



,'*<r ^ 



TRANSFORMtR 

 a4 25. F- 



TRANSFORMEO 



F+ TO a + 



Diagram vi. 



Galton also transformed a mosaic St George's Cross into a St Andrew's 

 Cross (slide.s in (ialtoniana). It may be said of these results that they were 

 only })artially successful — this is the view taken by Sir George Darwin in 

 his account of Galton in the Dictionary of National Biography {Second Suppl. 

 Vol. II, p. 72). But Galton recognised the main difficulty hunself: 



