mean duration of each for every month, being accurately computed, set off on the band accordingly, and noted in written characters on the upper or daylight part, whilst the name of the month is written in large capital letters at the bottom in white, on the dark ground of the nocturnal portion. The sun pouring down a cone of yellow rays, accompanied by the sign of the zodiac proper to each month, is also seen on the left of the upper part of each margin, and the moon on the lower half opposite to him.” The author gives further proof that these medallions are the work of Luca della Robbia, believing the fact to be as certain as anything not absolutely authenticated can be. Luca della Robbia was born about the year 1400, and his name must ever be associated with the discovery or adaptation on a large scale, and improvement in composition, of stanniferous enamel. That the nature of this enamel is different from what was used upon other pottery of the time may be seen by a comparison of the two surfaces. The greater degree of opacity and solidity in the former is a marked variation from that in general use; so with the surface of his painted tiles. Perhaps the earlier productions of the Caffaggiolo furnaces approach the nearest to it. There is no piece, seemingly, of the production of a Florentine or Tuscan pottery with a date before 1477, and this example would appear to be tin-glazed. With that exception, the first pieces surfaced with the stanniferous enamel are ascribed to the Caffaggiolo pottery and are dated 1507 and 1509, some seventy years subsequent to its first recorded use by Luca della Robbia; and we have no specimens which can with any probability be ascribed to a period within a quarter of a century of its habitual application by him. We cannot, therefore, find the slightest evidence to disprove the assertion of Vasari and others that Luca was the discoverer, for Italy, of this important improvement in the glazing of earthenware vessels. It is not, however, unreasonable to suppose that its composition may have been communicated to him by one of the Moorish potters from Spain, and that, acting upon this communication, he made a series of experiments resulting in the perfection to which he attained, and which result was guarded as a family secret by two succeeding generations.