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.
Murfreesboro is a city in Pike County, Arkansas, United States. The population was 1,764 at the 2000 census. The city is the county seat of Pike County. Crater of Diamonds State Park is located just to the south. The crater is an eroded lamproite pipe where diamonds were discovered in 1906. 100,000 were found by 1933, and visitors to the park may still take away whatever they can find.