Lampblack has the same chemical properties as charcoal, and being remarkably fine, and containing sometimes a portion of oil, is used on that account in the composition of some fire-works. Its quality may be known by its colour, and, when burnt, leaving no residue. It may be sufficient to remark, that like charcoal, it decomposes nitric acid; and the nitrates, when mixed with it, and projected into a red-hot crucible, will deflagrate or produce a vivid combustion. It may therefore be used in all kinds of fire-works, in which charcoal is employed. Concentrated nitric acid, when poured on lampblack, previously dried, will produce combustion. It is to the carbon, as well as the hydrogen, in oil of turpentine, that turpentine inflames when brought in contact with nitric acid; and although much charcoal is deposited, yet a considerable part passes off in the state of carbonic acid gas. By a proper treatment, lampblack like charcoal may be converted into artificial tannin by nitric acid. It has also antiseptic qualities; but to be used for this purpose it should first be exposed to heat, in order to drive off any oil which it may have contracted, or with which it might be contaminated. The quality of lampblack may, we suspect, be improved by bringing it to a state of ignition in close iron vessels. If required intensely black, as for the making of printers' ink, this process might be advantageously used. Mixed with gum water, it makes a durable writing ink, or, according to Mr. Close, by mixing it with a solution of copal in oil of lavender. This ink is not, like the common kind, acted upon by acids. _Sec. IX. Of Soot._