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Porphyrites, Porphyry

Porphyrites, Porphyry Page of 453 Prasius, Plasma Text size:minus plus Restore normal size   Mail page  Print this page
PORPHYRITES.
287
such evident facility is entirely lost. At present when employed in architectural decoration the only method of subduing the stone is to steep it for many weeks in urine, and even then it speedily turns the edge of the best steel tools. It has therefore been conjectured that the old sculptors worked both this and Basalt by means of emery-powder and chisels of soft metal. It is known that the early Egyptians executed their stupendous works in hard stones with bronze chisels, some of which have been found in the quarries.
The Grand Duke Cosimo I. was mightily vain of a discovery how to temper steel tools by some chemical means so as to cut Porphyry (Galluzi, iii. 127), and several statues executed by his order still adorn the entrance to the Boboli Gardens ; but their execution is rough and clumsy, not approaching in the least to the beautiful polish of the ancient works in Porphyry.
Porphyrites, Porphyry Page of 453 Prasius, Plasma
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