40 ENGLISH MEN OF SCIENCE. [CHAP. 



trial, owing to the impossibility of obtaining good 

 historical portraits. The value of these is further 

 diminished by the passion of distinguished indi- 

 viduals to be portrayed in uniforms, wigs, robes, 

 or whatever voluminous drapery seems most 

 appropriate to their high office, forgetting that 

 all this conceals the man. The practice might 

 well become common of photographing the 

 features from different points of view, and at 

 different periods of life, in such a way as would 

 be most advantageous to a careful study of 

 the lineaments of the man and his family. The 

 interest that would attach to collections of these 

 in after- times might be extremely great. 



PEDIGREES. 



Thirteen families have been selected, out of 

 those to which about 120 of the scientific men on 

 my list belong, as appearing noteworthy for their 

 richness in ability during two, three, or more 

 generations, or for any other peculiarity ; in some 

 cases they are also remarkable for purity of type. 

 The facts may for the most part be verified by re- 



