The firing shrinkage of a clay is usually about the same as the drying shrinkage. Total shrinkage will usually be about 8-12%. The next stage that happens during the firing process is vitrification. This is the hardening, tightening and finally the partial glassification of the clay. Vitrification results from fusions or melting of the various components of the clay.
Middlesboro is served by the Middlesboro-Bell County Airport, which is a single runway, general aviation airport and is the second oldest airport still in use in Kentucky, ranking behind Bowman Field in Louisville.. The airport was established in 1944, however, the first recorded flight into the city was in 1912.
Madison County is one of the fastest growing areas in Kentucky. It is rich in heritage and history. The County is unique in that it has two incorporated cities, Richmond and Berea. The County sits below Fayette County with the Kentucky River as its border. Madison County is a blend of urban, suburban and rural environments. It is a rapidly growing county enjoying both residential and industrial growth. As a tourist site, the County offers many attractions.