Original (inglés)

PREFACE This Lecture was delivered at the South Kensington Museum, in aid of the College for Working Men and Women.  As the Publishers, perhaps erroneously, believe that some of the few authors who were not present may be glad to study the advice here proffered, the Lecture is now printed.  It has been practically re-written, and, like the kiss which the Lady returned to Rodolphe, is revu, corrigé, et considerablement augmenté. A. L.