Before proceeding to the usual divisions hitherto observed, there is one point demanding special attention, viz., the Persian _reflet métallique_, or metallic lustre. The use of metallic-lustre pigments was, as has been already stated, known in the Balearic Islands, and gave the _original_ majolica its distinctive appearance. Long before that date the process was known to the Persians in connection with silicious glaze. The metallic lustre has also been found on Arabian specimens. It is in Persia, however, that we must, in all likelihood, look for its origin. The date of its invention cannot be fixed with even an approximation to precision. The probability is that it was never very extensively used, and the specimens obtained are mostly fragmentary. Many of these are from the ruins of Rhages, a city which stood about seventy miles south of the Caspian Sea. Earthquake and conquest successively laid this city in ruins, and each time that it was rebuilt its limits became more contracted. It was finally destroyed during the Mogul irruption under Hulaku Khan, in 1250, and it is from the ruins beyond the city of that era that the above mentioned fragments have been taken. In fixing the origin, therefore, of metallic lustre, the latest date would be six hundred and twenty-seven years ago, the most remote perhaps over two thousand. The metallic-lustre pigments were made use of as late as the time of Shah Abbas, who reigned from 1555 to 1628, and whom Jacquemart calls the “Louis XIV. of Iran.” POTTERY. Composition.--Caution in Looking at Specimens.--Wall-Tiles and their Decoration.--Vases. [Illustration: Fig. 142.--Shrine of Imam Hussein, at Kerbela. Showing the Use of Tiles in Persian Architecture.]