2 charts - Plate I-r (approximately 26 by 32 in.) for Determining the Inclusion Content of Steel - This wall chart includes Thin Series and Heavy Series: A-Sulfide Type, B-Alumina Type, C-Silicate Type, and D-Globular Oxide Type for Comparison with Field Area on Specimen of 0.50 mm2/0.000779 in2 (Square Field with sides 0.71 mm/0.0279 in.) at Magnification of 100 Diameters. Plate II - (approximately 15 by 20 in.) is a chart for determining the silicate and oxide inclusion content of steel, magnification at X 100.