William Burton and Henry Beauchamp Walters, 1911 Encyclopædia Britannica (1911)
“ The portrait busts are perfect models of iconic sculpture. In some respects the use of'burnt clay for sculpture has great advantages over that of marble; the soft clay is easily and rapidly moulded into form while the sculptor's thought is fresh in his mind, and thus works in terracotta often possess a spirit and vigour which can hardly be reproduced in laboriously finished marble. ”
