Читать книгу The History of Chemistry - Thomas Thomson - Страница 17

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The manufacture of stoneware vessels was known at a very early period of society. Frequent allusions to the potter’s wheel occur in the Old Testament, showing that the manufacture must have been familiar to the Jewish nation. The porcelain of the Chinese boasts of a very high antiquity indeed. We cannot doubt that the processes of the ancients were similar to those of the moderns, though I am not aware of any tolerably accurate account of them in any ancient author whatever.

Moulds of plaster of Paris were used by the ancients to take casts precisely as at present.93

The sand of Puzzoli was used by the Romans, as it is by the moderns, to form a mortar capable of hardening under water.

Pliny gives us some idea of the Roman bricks, which are known to have been of an excellent quality. There were three sizes of bricks used by the Romans.

1. Lydian, which were 1½ foot long and 1 foot broad.

2. Tetradoron, which was a square of 16 inches each side.

3. Pentadoron, which was a square, each side of which was 20 inches long.

Doron signifies the palm of the hand: of course it was equivalent to 4 inches.