Arseniate of Copper

In addition to our former figures of Arseniate of Copper, tabs. 168, 169, 170, I am happy to figure these curious varieties, not merely because they are rare, hut as examples that are of more consequence, as they will explain many groups of this substance that are scarcely, if at all, understood, The present rotate specimens, if I may so call them, are, as it were, a congeries formed of the truncated triedral column, chiefly like the left hand bottom outline. The other outline shows, by the small dots, that one of the solid angles is sometimes replaced by a new face, which would give it a wedge form, very applicable to the rotate formation of the upper specimen: they, however, seem more perfect columns, and are placed among each other somewhat upon the principle of the Galena in tab. 131. The middle outline shows the columnar sides and the triangular ends, nearly as they appear when magnified. Some are very small, and others larger and more irregular, somewhat approaching the broad faces, and even the mackles, as in the next figure.