The mordenite-type began to appear where n was about 8, diminished as n approached 12, and was produced in highest yields where n had an intermediate value. The analcime-type Na-B, crystallized in high yieds for n = 4 or 5 , but the yield rapidly decreased for n = 4 and slowly for n = 5. Some na-B was obtained even in the range where Na-D was the principal apecies.