Ruggieri may be regarded as the last of the ancients. It is true that his book shows a marked advance on anything that had gone before, also that he appears to have been one of the first, if not actually the first, to introduce the use of metal salts in the production of colour. But he makes no reference to the use of chlorate of potash, and it is the introduction of this salt into pyrotechny which marks the commencement of the modern epoch of the art. This earliest use of chlorate, or as it was then called, oxymuriate or hyperoxymuriate of potash, appears to have been soon after its discovery in 1786 by Berthollet. Samuel Parkes, in a work on chemistry written in 1811, says: “The shocking death of two individuals in October, 1788, and the burns others have suffered by it, render it feared by chemists in general,” that is in conjunction with sulphur and charcoal. He later remarks that notwithstanding this accident “the French have since —— actually employed in one of their campaigns gunpowder made with oxymuriate of potash instead of saltpetre,” and adds that a Scotch clergyman had taken out a patent for the use of a powder containing chlorate of potash to be fired by percussion. This patent, granted in 1807, is the first for the percussion system in firearms. The use, however, of chlorate of potash in propellant compositions presents no very great advance in pyrotechny, however revolutionary may have been the introduction of the percussion system into the manufacture of firearms. It is its use in the production of colour that marks the modern epoch. The exact date of this innovation appears to be about 1830. A Belgian lieutenant of artillery, Hippert by name, published in 1836 a translation of a work by Captain Moritz Meyer, of the Prussian Artillery, on the application of chemistry to artifices of war. In a chapter devoted to coloured fires he gives several formulæ containing chlorate of potash. Although this appears to be the first published notice of its use, it seems likely that by the time the book was published that it was fairly well established. Meyer concludes his remarks on coloured composition by saying that the English at that time made use of coloured rockets for signalling at sea, and had succeeded in producing ten different shades, “which are quite sufficient for the purpose of signalling particular pieces of information.” This seems rather to indicate that the elaboration if not the first introduction of chlorate of potash into pyrotechny may be attributed to this country. His mention of ten distinguishable tints, however, is somewhat optimistic. During the late war it was found that to avoid any chance of a mistake in code signals only three colours could be used for long-distance signalling, namely, red, green, and white.