Part 30 (2/2)

_Phosphorescent_, having a phosphoric property, eht like phosphorus

What is arsenic?

A heavy hly inflammable; so caustic or corrosive to animals, as to become a violent poison in all its states In its metallic state it is used in several of the arts: it is employed in the manufacture of factitioussoenerally co of slass, to which it gives transparency; in whitening copper; in calico printing; in the preparation of colors for the painter; and in the working of platina, and some other metals, to render the

_Corrosive_, apt to corrode, to eat away, to penetrate

How is the white powdered arsenic prepared?

By sub heat in a peculiar kind of furnace; this produces a dark grey powder, which is again heated in close iron vessels; this separates it from its impurities, and the arsenic is obtained in thick, solid masses; these, by exposure to the air, fall into a fine, white powder

From what is the word arsenic derived?

Fro _ out of land, in the Mendip Hills, in great quantities It has so strong a corrosive quality as sometimes to burn the hands and feet of the miners; it is a deadly poison for all known animals This poisonous enerally united with metallic ores

What do you em is used as a common name for all precious stones or jewels; they consist of the siliceous earths; and are much valued for their lustre, transparency, color, hardness, and rarity There are uished by its peculiar character

How are they divided?

Into the pellucid gereat lustre, and extremely hard, as the diamond; the sereat beauty; those of one color, as the eated or veined with different colors Geular shapes, with a natural polish, near the beds of rivers after great rains; these are of the pebble kind

Soh coat, in h not stones, are also ranked aems

_Pellucid_, clear as a drop of water

_Semi-pellucid_, half pellucid

Describe the Diamond

The diaems, and valued for its beautiful lustre; it is the hardest of all stones, as well as the most valuable The most esteemed are colorless A diamond in its natural state as it coh, because it has no brilliancy, but is covered with an earthy crust The diamond is the Adamant of the ancients; hence the expression ”hard as ada the hardest substance in nature The cutting of diareat skill; the polishi+ng is performed by a mill of simple construction

Where are they mostly found?

In yellow ochreous earths; in mines; and likewise in torrents, which have torn them from their beds In forht from the famous mines of Golconda, in Hindostan; the islands of Molucca and Borneo have also produced many valuable stones The diamond mines of Golconda are now so exhausted, that they are not thought worth the expense of working; these geht chiefly from Brazil, in South America