Tin-glazing in the kiln atmosphere and therefore a flame-burning kiln. Traditional kilns were wood firing, which required the pots to be protected in the glaze and luster firings by saggars or to be fired in a muffle kiln. Except for those making luster ware, modern tin-glaze potters use electric kilns. The recrystallisation of tin oxide during the firing provides evidence of the slightly different methods of different production sites, as the crystal size, the distribution and the concentration may be influenced. For instance, the analysis of the 14th century Islamic tin glazes from eastern Spain indicates that these samples may be
Wedding anniversary widely marked as her Diamond Jubilee. The origins of the current gift conventions date to 1937. Before that, only the 1st, 5th, 10th, 15th, 20th, 25th, 50th, and 75th anniversaries had an associated gift. In 1937, the American National Retail Jeweler Association (now known as Jewelers of America as a result of an organizational merger) introduced an expanded list of gifts. The revamped list gave a gift for each year up to the 25th, and then for every fifth anniversary after that. Lists of wedding anniversary gifts vary by country. The traditional and modern U.S. versions were compiled by librarians