Chloride of copper is a mineral of a green or greenish black color, and adamantine or vitreous luster. It occurs in massive fragments, in rhombic prisms and rectangular octahedrons, which give off fumes of hydrochloric acid gas when heated before the blowpipe. This compound is found in Saxony, the neighborhood of Vesuvius, and the desert of Atacama, between Chili and Peru. In Chili this mineral is ground into powder, and sold under the name of arsenillo, as a sand for dusting letters. A NEW COMET.Chloride of copper is a mineral of a green or greenish black color, and adamantine or vitreous luster. It occurs in massive fragments, in rhombic prisms and rectangular octahedrons, which give off fumes of hydrochloric acid gas when heated before the blowpipe. This compound is found in Saxony, the neighborhood of Vesuvius, and the desert of Atacama, between Chili and Peru. In Chili this mineral is ground into powder, and sold under the name of arsenillo, as a sand for dusting letters. A NEW COMET.—H. P. Tuttle, of the Harvard College Observatory, discovered a telescopic comet on the evening of the 4th inst. It was first seen at half-past seven P. M., and makes the fourteenth comet discovered at that Observatory. It is in the northern part of the heavens, and can only be seen with a powerful telescope. We Americans have manufactured 25,965 miles of railroad, which, if it could be stretched in one continuous line around the waist of Mother Earth, would still leave her about a thousand miles for a bow-knot. H. P. Tuttle, of the Harvard College Observatory, discovered a telescopic comet on the evening of the 4th inst. It was first seen at half-past seven P. M., and makes the fourteenth comet discovered at that Observatory. It is in the northern part of the heavens, and can only be seen with a powerful telescope. We Americans have manufactured 25,965 miles of railroad, which, if it could be stretched in one continuous line around the waist of Mother Earth, would still leave her about a thousand miles for a bow-knot.