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
Institute for the Study of Academic Racism Institute for the Study of Academic Racism The Institute for the Study of Academic Racism (ISAR) is an organization that monitors "changing intellectual trends in academic racism, biological determinism, and eugenics." ISAR states that in this capacity it "acts as a resource service for students, academics, journalists, legislators and civil rights activists." ISAR was founded by Barry Mehler in 1993. The institute maintains an online presence housed by, but independent from, Ferris State University. Proponents of eugenics such as the late Glayde Whitney accused Mehler of using what they perceive as "inquisition-like" tactics in order to discredit controversial scientists such