PATENTS

1948. KRCZIL, F. [Siliceous Material.] Czechoslovak Patent 60,124, no date. Kanier, p. 34.

See German Patents 581,123 (abs. 1952) and 596,093 (abs. 1951), French Patent 748,584 (abs. 1949), and Spanish Patent 129,625 (abs. 1950).