THE HAMILTON ASSOCIATION. 65 



the greater part of which was absorbed into the substance of the 

 "piece," thereby increasing its hardness and leaving only a faint 

 polish on the surface of the ware. 



Slip or Eftgobe. — Pesseri instances the use of glaze on tiles upon 

 a tomb in Bologna, opposite San Domenico, dated about 1 1 oo, and 

 further states — but it is not known on what authority — that it was 

 about the year 1300 that the method of covering clay with a "slip " 

 or " engobe " of pipe clay on the coarser earth of Verona was first 

 adopted. 



Glaze. — Slightly baked it was glazed with " Marzo Cotto " (oxide 

 of lead and glass) applied wet, and then fired ; this glaze was 

 variously colored, yellow, green, black and blue by antimony, iron, 

 manganese and cobalt. A similar method of glazing seems to have 

 been known in Germany, England and France from a remote period, 

 but was not in general use. 



Tin Glaze. — It was found by the addition of a certain portion 

 of oxide of tin, to the composition of glass and oxide of lead, that the 

 character of the glaze entirely alters, and instead of being translucent it 

 becomes, on fusion, an opaque and beautifully white enamel (the 

 intervening process of covering the coarse clay with a stratum of 

 white earth being unnecessary) it moreover was found to afford a 

 better ground for the application of ornament. The process of applica- 

 tion was the same as for slip. After immersion in the enamel bath and 

 subsequent drying, the painting is applied on the absorbent surface, 

 the piece being then subjected to the fire, which at one application 

 fixes the colors and liquefies the glaze. This enamelled pottery is by 

 far the most important group of glazed wares, being susceptible of 

 decoration by the lustre pigments, as well as by painting in colors, 

 with great delicacy ; it comprises the " Hispano-Moresque," the 

 " real Majolica " and the perfected earthenware of Italy and other 

 countries. 



Lustres. — The earliest traces of the use of Stanniferous enamel 

 glaze in Europe known to us, is always in connection with a decora- 

 tion produced by the reduction of certain metallic salts in the 

 reverbatory furnace, leaving a thin film on the surface and giving 

 the beautifully rich effect, known as "reflet metallique," "nacre- 

 cangiente," " Rubino," " Reverberato," and, in England, as "lustred 

 wares." In Italy the use of metallic lustres was apparently known and 



