A concavo-convex shaped clear glass with ground edges 2 mm thick used normally as receptacle for material under observation or to cover beakers when boiling solutions. The meniscus shape prevents the glass from sliding off the beaker land also returns the condensate. Diameter 25 mm   1" 40 mm   1½" 50 mm   2"  70 mm   2¾" 75 mm   3"80 mm   3¼" 90 mm   3½"100 mm  4"125 mm  5" \150 mm  6"200 mm

A concavo-convex shaped clear glass with ground edges 2 mm thick used normally as receptacle for material under observation or to cover beakers when boiling solutions. The meniscus shape prevents the glass from sliding off the beaker land also returns the condensate. Diameter 25 mm   1" 40 mm   1½" 50 mm   2"  70 mm   2¾" 75 mm   3"80 mm   3¼" 90 mm   3½"100 mm  4"125 mm  5" \150 mm  6"200 mm