In all relievo, as the shadows fall upon the background, the peculiar adaptation to architecture is manifest. As they are intended for minute inspection, gems are generally in mezzo-relievo. The workers in bronze and the goldsmiths--the former from the facility in casting, the latter for the minuteness and less distinctness of their works--adopting the flattest kind of mezzo-relievo, fancifully deviated from the original purity of the style, by introducing landscape and building backgrounds. An artist of the greatest genius fell into this error--Lorenzo Ghiberti, in the beautiful bronze doors of the baptistery of San Giovanni at Florence. In these celebrated compositions he attempted the union of basso-relievo with the principles of painting. His excellent workmanship and skill in composition was such as led the sculptors of the fifteenth century to consider this innovation upon the old simplicity an improvement. In inferior hands the failure would have been manifest, for the practice is in violation of the principle which the character of the material should determine. That Ghiberti was led into the error is not surprising, as he learned his art from a goldsmith. In his case it was a singular instance of ill-constituted judges choosing well. The judges who selected Ghiberti from his many competitors, were goldsmiths, painters, and sculptors--the majority were likely to favour that which approached nearest to their own practice. It is to the credit of our Flaxman that he revived the purer taste. This whole essay on relievo should be read attentively: it is so connected in all its parts that it is impossible to give its true character by either a few quotations or an at tempt at analysis.