The British squadron suffered 28 casualties from this bombardment.[167] Iznik pottery: Produced in Ottoman Turkey as early as the 15th century AD.[168] It consists of a body, slip, and glaze, where the body and glaze are "quartz-frit."[169] The "frits" in both cases "are unusual in that they contain lead oxide as well as soda"; the lead oxide would help reduce the thermal expansion coefficient of the ceramic.[170] Microscopic analysis reveals that the material that has been labeled "frit" is "interstitial glass" which serves to connect the quartz particles.[171] Standing army with firearms: The Ottoman military's regularized use of firearms proceeded ahead of the pace of their European counterparts.