Petrography lower if wholly or partly vitreous. The specific gravity of the more common rocks range from about 2.5 to 3.2. Archaeologists use petrography to identify mineral components in pottery. This information ties the artifacts to geological areas where the raw materials for the pottery were obtained. In addition to clay, potters often used rock fragments, usually called "temper" or "aplastics", to modify the clay's properties. The geological information obtained from the pottery components provides insight into how potters selected and used local and non-local resources. Archaeologists are able to determine whether pottery found in a particular location was locally produced
This Is What You Want... This Is What You Get were not re-recorded for "This Is What You Want...This Is What You Get" (although a remixed version of "Blue Water" was included as the B-side on the "This Is Not a Love Song" 12" single). Songs on "This Is What You Want...This Is What You Get" which did not appear in any form on "Commercial Zone" are "Tie Me to the Length of That", "The Pardon" and "1981", and are the only songs on the album which do not credit Keith Levene as a co-writer. PiL was supposed to score the soundtrack for the 1983 suspense film "Copkiller", starring Harvey