1991.064.099
Print, Photographic
Black and white photographic print depicting equipment in the Chemical Laboratory at the Champion Spark Plug Co.
Caption on verso reads, "Showing equipment for making thin section. Proper control of the quality of the porcelain must necessarily include frequent petrographic examination. For this purpose porcelains are sawed into this section and these are polished down until they are one-thousandth of an inch thick."
